Visual Basic – Amjad Izhar Blog

The provided texts introduce Visual Basic programming, emphasizing practical application development for various platforms. They commence by guiding users through Visual Studio 2015 installation, particularly the custom setup to include essential programming languages like Visual C++, F#, Python tools, and development kits for Universal Windows Platform and cross-platform mobile development using Xamarin. The content then transitions into fundamental Visual Basic syntax, explaining code structure, variables (integers, strings), data types, operators, and conditional logic using if/else statements. It also covers iteration statements like For/Next and While/Do While loops, along with arrays, string manipulation, and the creation of custom methods (subroutines and functions), including overloaded methods and passing parameters by value (ByVal) versus by reference (ByRef).

Visual Basic: A Programming Foundation

Visual Basic is a programming language designed to introduce absolute beginners to programming and building applications on the Windows platform. It aims to make programming concepts understandable and accessible.

Here’s a comprehensive discussion of Visual Basic based on the sources:

What is Visual Basic?

Purpose and Target AudienceVisual Basic (VB) is ideal for individuals completely new to programming, the VB language, and developing on the Windows platform. It emphasizes not just “what” to do, but “why” and the thought process behind it.
It’s used to build .NET applications.
The course explicitly states that this flavor of Visual Basic is not for creating macros in Excel or other Microsoft Office tools; that functionality is provided by Visual Basic for Applications (VBA). While VB and VBA may look similar, their capabilities are “extremely different”.
Readability and VerbosityVisual Basic is described as a “more human readable programming language” compared to others.
However, this readability “comes at a price”: it’s more verbose, meaning you have to use more keystrokes to build code instructions than languages like C#.
Despite this, there’s “virtually no difference” between applications created using C# and those created with Visual Basic because both compile into a .NET assembly.
Many fundamental programming concepts learned in Visual Basic transfer almost directly to C#.
Evolution and HistoryThe instructor, Bob Tabor, has taught Visual Basic to hundreds of thousands of people for over 14 years, including children as young as 8 and adults as old as 80.
The course itself is the sixth iteration, dating back to 2005, with feedback from thousands of students incorporated over the years.
Visual Basic holds a “special place” for the instructor as they learned the BASIC programming language at 12 years old. BASIC stands for “Beginners All-Purpose Symbolic Instruction Code”.
Visual Basic was one of the first applications that allowed users to visually design forms by dragging and dropping components from a toolbox onto a form designer.
Application ScopeAfter learning the basics, you can build a wide range of applications using Visual Basic, including web applications, Windows Store applications, cloud services, video games, and even applications for iOS and Android.

Key Tools: Visual Studio and the .NET Framework

Visual StudioVisual Studio is the Integrated Development Environment (IDE) where you write Visual Basic code.
The course assumes you have some version and edition of Visual Studio installed. The instructor uses Visual Studio 2015 Community Edition (a free version), but any edition or version is compatible, though minor user interface differences might exist.
Installation: Visual Studio can be downloaded from visualstudio.com. It’s recommended to choose the “Custom” installation option to ensure all necessary packages and libraries for your desired application types (e.g., universal Windows apps, cross-platform mobile development with Xamarin) are installed.
Project and Solution Structure:
Visual Basic code files are organized into projects, and one or more projects are organized into solutions.
A project (e.g., Hello World.vbproj) typically contains code files (e.g., Module1.vb), boilerplate code, and settings.
A solution (e.g., Example.sln) acts as an umbrella that owns projects, especially useful for complex applications with multiple related projects.
By default, projects are stored in your user’s Documents\Visual Studio\[Version]\Projects subdirectory, but they can be saved anywhere.
Projects are compiled into a single .NET assembly (an executable file or library).
Developer Tools within Visual Studio:
Solution Explorer: This window is your main navigational device for files and settings within your project and solution.
Code Editor: The main area where you type your Visual Basic code.
Intellisense: Provides helpful pop-up information and messages as you type, guiding you with available methods, properties, and parameters.
Error List: Displays compilation errors with hints and clues as to where problems exist in your code, often accompanied by red squiggly lines in the editor.
Debugging Tools: Visual Studio offers powerful debugging features to pause and watch the execution of code.
Breakpoints (red circles/octagons in the margin) can be set to stop program execution at specific lines.
You can step through code line by line (Step Over/F10) to observe variable values.
Watch windows (Autos, Locals, Watch) allow you to monitor variable values as they change.
Conditional breakpoints can be configured to stop execution only when specific conditions are met (e.g., an index equals 7).
Code Snippets: Shortcuts to generate common code blocks (e.g., typing for tab tab expands into a For Next loop template, if tab tab for an If statement).
.NET FrameworkThe .NET Framework is a collection of pre-built functionality created by Microsoft that developers can use in their applications.
It consists of two primary parts that concern beginners:
Class Library: A vast library of pre-written code that handles complex tasks like math operations, text manipulation, displaying things to the screen, or network communication. Developers can “borrow” or “use” this code rather than building it from scratch. Examples include the Console class and the Random class.
Runtime (Common Language Runtime or CLR): This acts as a “protective bubble” where your application runs. It manages low-level details such as interacting with the computer’s operating system, memory, and hardware. It also provides a layer of protection for the end-user against malicious software. The CLR is responsible for allocating memory space for variables based on their declared data types.

Fundamental Visual Basic Programming Concepts

Code Precision and ReadabilityWriting Visual Basic code is an exercise in preciseness. You must type code exactly as intended, including spelling and punctuation. Even minor deviations can prevent compilation or lead to errors.
Visual Basic is considered a “forgiving” language because it often provides hints (red squiggly lines, error list) to guide you to problems.
Indentation, white space, and color coding in Visual Studio enhance code readability, making it easier to understand the structure and hierarchy.
You can use a single quote (‘) to add comments to your code, which are ignored by the compiler.
A line continuation character (_) allows you to split long lines of code onto multiple physical lines for better readability without affecting execution.
Statements, Expressions, Operators, and OperandsStatements are complete instructions or “thoughts” in Visual Basic, analogous to sentences in English.
Expressions are components of statements, often evaluating to a value (e.g., userValue = 1, Console.WriteLine(“Hello World”)).
Operands are like nouns, representing “things” such as variables, literal strings, or literal numbers (e.g., x, “Hello World”, 7).
Operators are like verbs, performing actions on operands. Visual Basic has many built-in operators.
Assignment Operator (=): Used to set the value of a variable (e.g., x = 7).
Arithmetic Operators (+, -, *, /): Standard mathematical operations.
Equality Operator (=): Used in conditions to check if two values are equal (e.g., userValue = 1 in an If statement).
Comparison Operators (>, <, >=, <=): Used for numerical or alphabetical comparisons.
String Concatenation Operator (&): Used to append or tie together strings (e.g., “Hello ” & myFirstName).
Compound Assignment Operators (+=, -=, &=): Shortcuts for combining an operation with assignment (e.g., guesses += 1 is equivalent to guesses = guesses + 1).
Member Access Operator (.): Used to access members (properties or methods) of an object or class (e.g., Console.WriteLine).
Method Invocation Operator (()): Parentheses after a word indicate that a method is being called or invoked. They can contain input parameters.
Variables and Data TypesA variable is conceptually a “bucket in your computer’s memory” that can hold a value. Values can be stored, retrieved, or overwritten in variables.
You declare a variable using the Dim keyword (short for “dimension”) and must specify its data type using As [DataType] to tell the .NET runtime how much memory to allocate (the “size of the bucket”).
Key Data Types Covered:
Integer: For whole numbers without decimal points, ranging from approximately -2 billion to +2 billion.
String: For sequences of characters (text).
Boolean: For true/false values.
Date: For storing dates and times.
TimeSpan: For representing a duration or span of time between two dates.
Decimal: For monetary values, allowing precision after the decimal point.
Initialization: It’s good practice to initialize variables by setting their value immediately upon declaration, putting them into a “valid state”.
Case Insensitivity: Visual Basic is case-insensitive, meaning myfirstname and MyFirstName refer to the same variable. You cannot declare two variables with the same name, even if their casing differs.
Type Conversion: You can convert values between data types using functions like CInt() (convert to Integer) or CStr() (convert to String), or methods like .ToString().
Input and OutputConsole.WriteLine(): Displays a line of text to the console window and then moves the cursor to the next line.
Console.Write(): Displays text but keeps the cursor on the same line, allowing user input to appear immediately after the prompt.
Console.ReadLine(): Used to pause the application and wait for the user to press Enter. It can also capture and return the text typed by the user before they press Enter.
Console.Clear(): Clears all text currently displayed in the console window.

Control Flow: Decisions and Iterations

Decisions (Conditional Logic)If…Else If…Else…End If: This structure allows your application to execute different blocks of code based on whether a given condition is True or False.
A simplified If statement can use the Then keyword to put a simple check and its result on a single line.
The IIf() function is a compact way to perform a conditional evaluation and return one of two values based on the result.
Iterations (Loops)For Next: Used to execute a block of code a preset number of times. It typically uses an index variable that iterates from a starting value to an ending value. You can use Exit For to prematurely break out of the loop. The Step keyword allows the index to increment by a value other than one (e.g., Step -1 for backward iteration, Step 2 to count by twos).
For Each: Provides an elegant way to iterate through each item in an array or collection, without needing to manage indexes or lengths explicitly. It temporarily copies the current item’s value into a variable for use within the loop.
While…End While: This loop repeatedly executes a block of code as long as a specified condition remains True. The condition is checked before each iteration, so the code block might not run at all if the condition is initially False. This is useful when the number of iterations is not known in advance.
Do While: Similar to While, but it guarantees that the code block will execute at least one time before the condition is checked. The condition is evaluated at the end of the loop body.

Data Manipulation

ArraysAn array is a way to work with several related values of the same data type, treated as a single unit or “bucket” containing smaller “sub-buckets”.
Arrays are zero-based, meaning the first element is at index 0. When declaring, the number in parentheses specifies the highest index, so Dim numbers(4) As Integer creates an array with 5 elements (0 through 4).
Individual elements are accessed using their index in parentheses (e.g., numbers(0)).
The .Length property can be used to determine the total number of items in an array.
Attempting to access an array element outside its defined range will result in an IndexOutOfRangeException at runtime.
Arrays can be initialized directly with values when declared, allowing the compiler to determine the size based on the provided values (e.g., Dim numbers() As Integer = {4, 8, 15}).
A String is internally treated as an array of individual characters.
The String.ToCharArray() method can convert a string into an array of characters.
The Array.Reverse() method can be used to reverse the order of elements in an array.
The String.Concat() method can combine elements of a character array back into a single string.
String ManipulationVisual Basic and the .NET Framework offer extensive functionality for manipulating strings.
Special Characters: To include a literal double quote within a string, use two double quotes (“”) together (e.g., myString = “my “”so-called”” life”). You can insert new lines using vbNewLine and tabs using vbTab constants.
Formatting with String.Format(): This method allows you to create formatted strings using replacement syntax ({0}, {1}, etc.) within a template string. It also supports custom format codes (e.g., {0:C} for currency, {0:N} for numbers with commas, {0:P} for percentages, or custom patterns like ###-###-#### for phone numbers).
Common String Methods:
.Substring(): Extracts a portion of a string.
.ToUpper() / .ToLower(): Converts the entire string to uppercase or lowercase.
.Replace(): Substitutes occurrences of specified characters or substrings with others.
.Length: Returns the number of characters in the string.
.Trim() / .TrimStart() / .TrimEnd(): Removes leading and/or trailing whitespace characters.
String Immutability and StringBuilder: Strings are immutable in Visual Basic. This means that every time you modify a string (e.g., append characters), a new string object is created in memory, which can be inefficient for frequent modifications. For extensive string appending, the StringBuilder class is more memory-friendly as it allows mutable string operations. It requires importing the System.Text namespace.
Date and Time ManipulationThe Date data type is used to work with specific points in time. Its default value is January 1st, 1 AD at midnight.
The Now function provides the current date and time.
Formatting Dates and Times: The Date type has built-in methods like ToLongDateString(), ToShortDateString(), ToLongTimeString(), and ToShortTimeString() to display dates and times in various common formats based on the computer’s regional settings. You can also use the .ToString() method with custom format strings (e.g., MMMM for full month name, hh for 12-hour clock) for highly specific formatting.
Date Math: You can add or subtract units of time (days, hours, minutes, months, years) using methods like AddDays(), AddHours(), etc. To subtract, pass a negative number to these methods.
Initializing Dates: You can create Date objects for specific past or future dates using a constructor (e.g., New Date(year, month, day)) or by parsing a string representation of a date (Date.Parse(“string date”)). Literal dates can also be expressed by enclosing the date in pound symbols (#) (e.g., #12/7/1969#).
TimeSpan: The TimeSpan data type represents a duration of time. You can calculate a TimeSpan by subtracting one Date from another (e.g., Date.Now.Subtract(myBirthdate)) and then access total days, hours, or minutes within that span. You can also add TimeSpan values to dates or other TimeSpan values.
Just like with strings, it’s recommended to explore the many built-in functions for date and time manipulation rather than writing complex custom code.

Object-Oriented Programming (OOP): Classes and Methods

The Conceptual Jump to ClassesWhile modules serve as containers for methods, classes have a special purpose related to Object-Oriented Programming (OOP). OOP can be a conceptual hurdle for new developers, but it’s crucial for building larger, more maintainable applications.
A class is a blueprint, pattern, or cookie cutter that defines the structure and behavior of a specific type of data or entity (e.g., a “Car” class defining what a car is in your application).
An object is an instance of a class created in the computer’s memory based on that blueprint (e.g., “myCar” is an object, an actual instance of the “Car” class). Each object is distinct and separate from other instances of the same class.
Every class implicitly inherits from System.Object in the .NET Framework, providing some basic functionality by default (e.g., ToString(), GetType()).
Defining Classes and PropertiesYou define a class using Public Class [ClassName] … End Class syntax, typically in a separate .vb file (e.g., Car.vb).
Properties define the attributes or characteristics of a class (e.g., Make, Model, Year, Color for a Car class). These are typically defined using Public Property [PropertyName] As [DataType]. This is a shorthand for an “auto-implemented property”.
Properties also have longer, “full-blown” versions with explicit Get and Set sections, allowing you to add custom logic like data validation or access control when a property’s value is retrieved or set.
Working with Objects (Instantiating Classes)You create an object (an instance of a class) using the New keyword (e.g., Dim myCar As New Car()). This New keyword acts like a “factory” that takes the class blueprint and creates a living object in memory.
Once an object is created, you can access its properties (to set or retrieve values) and call its methods using the member access operator (.) (e.g., myCar.Make = “Toyota”, Console.WriteLine(myCar.Year)).
Objects remain in memory as long as they are being used. When no longer referenced, they are eventually removed by the .NET runtime, freeing up memory.
Defining and Calling MethodsMethods are blocks of code defined within a class (or module) that perform specific actions. They help organize code, eliminate duplication, encapsulate functionality, and simplify maintenance.
Subroutines (Sub [Name](Parameters) … End Sub): These methods execute a block of code but do not return a value to the caller. They are “fire and forget”.
Functions (Function [Name](Parameters) As [ReturnType] … End Function): These methods execute a block of code and return a value of a specified data type to the caller.
Input Parameters: Methods can accept input parameters, which are values passed into the method to influence its behavior. Parameters are defined with a name and a data type, separated by commas.
Overloaded Methods: You can create multiple versions of methods with the same name, as long as they have different method signatures. A method’s signature is determined by the number and data types of its input parameters (parameter names do not affect the signature). Visual Studio’s Intellisense helps identify overloaded versions.
Passing Parameters by Value vs. by Reference:
ByVal (By Value): This is the default way parameters are passed. A copy of the variable’s value is sent to the method, so any changes made to the parameter within the method do not affect the original variable in the calling code.
ByRef (By Reference): When a parameter is passed ByRef, a reference to the original variable’s memory location is given to the method. This allows the method to directly manipulate the original variable in the calling code.
Code Readability and Strategy: It’s a best practice to strive for “human readable” code, making it “read as much like an English story as possible” by choosing good names for variables and methods. A general rule of thumb is to keep methods small, ideally no more than six lines of code, to maintain tidiness and readability.

This foundational understanding provides a strong base for learning and developing with Visual Basic.

Visual Studio: A Developer’s Essential Toolkit

Visual Studio is an integrated development environment (IDE) that serves as a primary tool for developing applications using Visual Basic and other programming languages on the Windows platform. It provides a comprehensive environment for writing, testing, and managing code.

Here’s a detailed discussion of Visual Studio based on the sources:

What is Visual Studio?

Visual Studio is specifically designed for building applications on the Windows platform.
It functions as the code editor where you type your lines of code.
The course assumes you have some version and edition of Visual Studio installed on your local computer to begin writing code.
While the course focuses on the fundamentals of the Visual Basic language itself, Visual Studio is the primary tool used for demonstrations and exercises.

Obtaining and Installing Visual Studio

You can visit visualstudio.com to learn about and download various free and commercial versions.
The instructor personally uses the Visual Studio 2015 Community Edition, which is a free version, for the course and his own work.
It is a web installer that initiates the installation routine upon running.
A custom installation option is highly recommended during setup to ensure you get all the necessary packages and libraries for the types of applications you wish to create.
By default, Visual Studio Community Edition installs C# and Visual Basic templates.
Through custom installation, you can add other programming languages like Visual C++, Visual F#, and Python tools.
You can also select components for Windows and web development, such as ClickOnce publishing tools, SQL Server data tools, PowerShell tools, and Silverlight development.
For developing Universal Windows Applications, the Universal Windows App Development Toolkit (including tools, emulators, and SDK) is crucial and easier to install during the initial setup.
Cross-platform mobile development tools (Xamarin platform) are available for creating applications for Windows Phone, iOS, and Android using C# within Visual Studio, and these include necessary emulators.
Installing all options can significantly increase the install size, potentially requiring up to 48 gigabytes across all drives.

Using Visual Studio for Development

Project and Solution Management:
When you create a new project (e.g., through File > New Project or the Start page’s “New Project” link), Visual Studio automatically opens relevant files, like Module1.vb, based on the chosen project template.
Project templates provide a starting point with boilerplate code and settings.
Files and settings are organized into projects, which are then compiled into a single .NET assembly.
One or more projects are organized into solutions.
The Solution Explorer (typically in the upper right) provides a tree-like view of project items and is the main navigational device for files and settings. You can double-click a file in Solution Explorer to open it in the main area.
Projects are saved by default in your user’s Documents\Visual Studio\[Year]\Projects folder.
Solution (.sln) and project (.vbproj) files are typically XML files for settings and should not be manually edited.
The bin directory within a project folder contains the compiled executable output (binary) after compilation.
Code Editing and Navigation:
The main area is where you type code, typically shown as a tabbed area like Module1.vb.
IntelliSense provides helpful pop-up windows with information and messages as you type, indicating expected input parameters and showing overloaded method versions.
Visual Studio assists with code formatting by providing default indentation levels to denote containment and improve readability, although indentation is optional for execution.
Color coding different types of instructions (e.g., literal strings in deep red, classes/modules in aqua, keywords in royal blue, comments in green) also enhances readability.
White space does not affect program execution but improves readability.
Running and Debugging:
The “Start” button (green arrow) on the toolbar or the Debug menu’s “Start Debugging” option runs the application.
When running, Visual Studio’s appearance changes, and a console window typically pops up.
You can stop the application by clicking the ‘x’ button on the console window or pressing the Enter key.
Error Handling: Visual Studio helps identify problems with red squiggly lines under problematic code and displays a list of errors in the Error List window if compilation fails. Hovering over a red squiggly line often provides vague explanations but indicates the problem area.
Debugging Tools are a key feature:
You can set breakpoints (represented by a circle in the gray column next to a line number) to pause code execution.
While paused, you can hover your mouse cursor over variables to see their current values.
The “Continue” button resumes execution, while “Step Over” (F10) allows you to execute code line by line.
The Autos, Locals, and Watch windows display variable values, with values turning red when they change. You can also “pin” variable values to keep them visible.
Conditional breakpoints can be configured to stop execution only when a specific condition is met (e.g., index = 7), or to log messages without stopping.
Breakpoints can be temporarily disabled or entirely removed.
Productivity Features:
Code snippets allow you to type a keyword (e.g., for, if) and then press Tab Tab to expand it into a full code template, with tab-navigable fields for customization.
Visual Studio automatically capitalizes keywords (e.g., dim to Dim, as to As, integer to Integer), which is a function of the IDE, not the Visual Basic language itself.
Tools on the toolbar like “comment out the selected lines” (Ctrl+K, Ctrl+C) and “uncomment the selected lines” (Ctrl+K, Ctrl+U) aid in code management.

Important Considerations for Visual Basic Development in Visual Studio

While Visual Basic is considered forgiving, precision in typing code is extremely important; even a single character deviation can prevent compilation.
Visual Basic is case-insensitive, meaning myfirstname and MyFirstName are treated as the same variable.
You cannot declare the same variable name twice within the same code block, regardless of casing.
When working with dates, strings, or other data types, Visual Studio, in conjunction with the .NET Framework Class Library, provides numerous built-in methods (e.g., ToString, Parse, Trim, AddDays, AddHours) for common manipulations. It’s advised to utilize these built-in functions rather than writing custom, complex code.
Visual Studio simplifies working with namespaces by offering suggestions (e.g., a light bulb icon) to import necessary namespaces (like System.Text for StringBuilder) when a class is not immediately found.

This course does not aim to be an exhaustive tour of Visual Studio; other resources on Microsoft Virtual Academy offer more in-depth coverage of its advanced features, workflow improvements, and version differences.

Visual Basic Programming Fundamentals and Concepts

Programming concepts encompass the fundamental ideas and building blocks used to write software applications. Visual Basic, as a programming language, alongside Visual Studio, an integrated development environment (IDE), provides tools and structures to implement these concepts for building applications primarily on the Windows platform.

Here’s a discussion of key programming concepts as detailed in the sources:

Core Building Blocks of Code

Statements: These are complete instructions or thoughts in Visual Basic, similar to sentences in English. They are executable instructions given to the compiler.
Expressions: Statements are composed of one or more expressions. Examples include a method call (e.g., Console.WriteLine(“Hello World”)), an evaluation in an If statement (e.g., userValue = 1), or an assignment (e.g., x = 7).
Operators: These are similar to verbs in a sentence and act on operands. They perform actions. Examples include:
Assignment operator (=): Assigns a value to a variable (e.g., x = 7).
Arithmetic operators: Addition (+), subtraction (-), multiplication (*), division (/).
Equality operator (=): Checks if two values are equal, used in contexts like If statements.
Comparison operators: Greater than (>), less than (<), greater than or equal to (>=), less than or equal to (<=). These can be used with numbers, dates, or strings.
Conditional operators: Logical And and Or to combine expressions.
Member access operator (.): Used to call a method or access a property of an object or class (e.g., Console.WriteLine).
Literal string operator (“”): Defines a literal string of characters.
Concatenation operator (&): Appends or ties together strings.
Method invocation operator (()): The parentheses used after a method name to invoke its execution.
Type declaration operator (As): Used to define the data type of a variable or property (e.g., Dim x As Integer).
Operands: These are similar to nouns and are the “things” that operators act upon. Examples include variables, literal strings, or literal numbers.

Code Structure and Readability

Keywords: Visual Basic uses specific keywords (e.g., Dim, As, Integer, Sub, Module). Visual Studio often auto-capitalizes these keywords for you.
Syntax Rules and Precision: Programming languages have specific syntax rules and precision is extremely important when typing code; even a single character deviation can prevent compilation. Visual Studio helps by providing red squiggly lines under problematic code and listing errors in the Error List window.
Indentation and White Space: While optional for execution, Visual Studio automatically indents code to denote containment and improve readability. White space also does not affect execution but significantly improves readability.
Color Coding: Visual Studio uses color coding for different types of instructions (e.g., literal strings in deep red, classes/modules in aqua, keywords in royal blue, comments in green) to enhance readability.
Code Comments: A single quote mark (‘) is used in Visual Basic to comment out a line of code, meaning the compiler will ignore it during execution. This is useful for experimentation without deleting code. Visual Studio also has toolbar buttons and keyboard shortcuts to comment/uncomment selected lines.

Data Management

Variables: A variable is fundamentally a “bucket” in your computer’s memory capable of holding a value. You can store, retrieve, and even overwrite values in a variable.
Declaration: You must declare variables using the Dim keyword and specify their data type (e.g., Dim x As Integer). This tells the .NET runtime to allocate appropriate memory space.
Initialization: You can set a variable’s value immediately at the point of declaration, which is called initializing. This puts the variable into a “valid state” and can reduce code.
Data Types: Visual Basic supports various data types to store different kinds of data:
Integer: For whole numbers without decimal places, capable of storing large positive or negative values (e.g., up to ~2 billion).
String: For sequences of individual characters (text). Strings can hold a lot of information and are considered “massive buckets”.
Boolean: For true/false values, requiring very little memory.
Date: For storing dates and times.
TimeSpan: For representing spans or durations of time between two dates.
Decimal: For precise monetary values or numbers with many decimal places.
Case Insensitivity: Visual Basic is case-insensitive, meaning myfirstname and MyFirstName are treated as the same variable. However, you cannot declare the same variable name twice within the same code block, regardless of casing. Visual Studio might automatically capitalize keywords for consistency, but this is an IDE feature, not a language requirement.
Type Conversion: It’s often necessary to convert values between data types (e.g., from a string retrieved from user input to an integer for calculations). Methods like CInt (convert to integer), CStr (convert to string), Parse (for dates), and ToString are used for this.
String Manipulation: Strings are “immutable,” meaning changing a string creates a new one in memory. For efficiency with large or frequently modified strings, the StringBuilder class is recommended. Common string manipulations include:
Escaping Characters: Using double double-quotes (“”) to represent a literal double quote within a string.
Special Characters: Using constants like VbNewLine for line breaks or VbTab for tab spacing within strings.
Formatting (String.Format): Using replacement syntax (curly braces {0}, {1}, etc.) to insert values into a string template, with options for specific formatting like currency (:C), numbers (:N), or percentages (:P).
Methods: Substring (to pull parts of a string), ToUpper (to uppercase), ToLower (to lowercase), Replace (to substitute characters), Length (to get string length), Trim (to remove leading/trailing spaces), TrimStart, TrimEnd.
Date and Time Manipulation: The Date data type provides methods for:
Getting Current Time: The Now function returns the current date and time.
Formatting: ToLongDateString, ToShortDateString, ToLongTimeString, ToShortTimeString for predefined formats. ToString with custom format strings (e.g., MMMM for full month name) for more control.
Calculations: AddDays, AddHours, AddMonths, AddYears, etc., to add time, or use a negative number to subtract time.
Creating Specific Dates: Using the New Date constructor with year, month, day, and optional time components, or Date.Parse to convert a string into a date.
Time Spans: The TimeSpan data type represents a duration of time and can be calculated by subtracting one date from another (Date.Now.Subtract(myBirthDate)). It offers properties like TotalDays, TotalHours, etc..

Program Flow Control

Conditional Logic (Decisions): This allows applications to execute different blocks of code based on conditions.
If…Then…ElseIf…Else…End If: Evaluates a condition; if true, a specific block of code executes. ElseIf provides alternative conditions, and Else acts as a catch-all if no preceding condition is true. A single If statement can be condensed onto one line using Then.
IIf (Immediate If) Method: A conditional method that evaluates a condition and returns one value if true, another if false, often used for assignments.
Iteration (Loops): These statements allow code blocks to be executed multiple times.
For…Next: Used to iterate a preset number of times, controlled by a counter variable, a starting value, and an ending value. The Step keyword can be used to count by increments other than one (e.g., Step 2 for odd numbers, Step -1 to count backwards).
For Each…Next: Iterates through each item in an array or collection, often more elegant for processing all elements without needing to manage indexes.
While…End While: Continuously executes a block of code as long as a specified condition remains true. This is useful when the number of iterations is not known beforehand.
Do While…Loop: Similar to While, but guarantees that the code block will execute at least once before the condition is evaluated.
Exit For: Used to break out of a For loop prematurely once a certain condition is met.
Debugging Tools: Visual Studio offers robust debugging capabilities to understand program flow:
Breakpoints: Set by clicking in the gray column next to a line number, they pause code execution at that point.
Conditional Breakpoints: Can be configured to stop only when a specific condition is met (e.g., index = 7).
Stepping Through Code: Step Over (F10) executes code line by line, allowing inspection of changes.
Variable Inspection: Hovering over variables reveals their current values, and windows like Autos, Locals, and Watch display values (which turn red when they change).

Code Organization and Reusability

Methods (Subroutines and Functions): These are named blocks of code that perform a specific task.
Benefits: They help to organize code, eliminate duplicate code (reducing the need for copy-pasting), encapsulate specific features (making them reusable), and simplify updates as changes only need to be made in one place.
Subroutines (Sub): Execute a block of code and then end quietly, without returning a value (e.g., DisplayResult).
Functions (Function): Execute a block of code and return a value of a specified data type (e.g., GetReverseString As String).
Input Parameters: Data can be passed into methods using parameters defined in their signature (e.g., (message As String)). Multiple parameters are separated by commas.
Overloading: Multiple versions of a method can be created with the same name but different method signatures (the number and data type of input parameters).
Passing by Value (ByVal) vs. by Reference (ByRef):
ByVal (default): A copy of the argument’s value is passed. Changes inside the method do not affect the original variable.
ByRef: A reference to the argument’s memory location is passed. Changes inside the method directly manipulate the original variable.
Code Readability: Good method names and breaking down large tasks into smaller methods improve code readability, making it easier for others (or your future self) to understand and maintain. A guideline, often called the “six-line rule,” suggests that no method should have more than six lines of code, promoting smaller, more focused methods.
Arrays: An array is a sequence or grouping of related data of the same data type, all collected under a single variable name.
Declaration: Declared with Dim and specified size (e.g., Dim numbers(4) As Integer for five elements, as arrays are zero-based) or initialized with values directly (e.g., Dim names() As String = {“Bob”, “Jim”}).
Accessing Elements: Individual elements are accessed using their index in parentheses (e.g., numbers(0)).
Length Property: Returns the total number of items in the array.
Runtime Exceptions: Trying to access an array element outside its defined range (an “index out of range exception”) will cause a runtime error.
Classes: A class is a blueprint or custom data type that serves as a container for related properties and methods.
Object-Oriented Programming (OOP): Classes introduce object-oriented programming concepts.
Object (Instance): An object is a concrete realization or instance of a class created in memory using the New keyword (e.g., Dim myCar As New Car). Just as many houses can be built from one blueprint, many distinct objects can be created from one class. Each object is separate and distinct.
Properties: These are attributes of a class or object (e.g., Make, Model, Year, Color for a Car class). They can be simple “auto-implemented” properties or “full-blown” properties with custom Get (retrieve value) and Set (assign value) logic for validation or access control.
Methods of a Class: Classes also contain methods (subroutines or functions) that define the behaviors of objects created from that class. For example, a Car class might have a DetermineMarketValue method.
Namespaces: Classes are organized into namespaces (e.g., System.Text for StringBuilder), which are like “last names” or “shelves” in a library to help locate them.
Inheritance: All classes in .NET, including custom ones, inherit from System.Object, providing some basic functionality for free (like ToString, GetType).

Understanding these programming concepts provides a solid foundation for developing applications in Visual Basic and beyond.

Visual Basic: Data Types and Variables

Data types are a fundamental concept in Visual Basic programming, defining the kind of data a variable can hold and how much memory it requires.

Here’s a discussion of data types based on the sources:

Purpose of Data Types
When you declare a variable, you must express your intent regarding the kind of data it will store. This is crucial for the .NET runtime (also known as the Common Language Runtime or CLR) to allocate space in your computer’s memory that is sufficiently large enough to hold the data.
By specifying a data type, you tell the runtime the “size of the bucket” you want to create in memory. This ensures that the data is handled correctly and efficiently.
Common Built-in Data Types
Integer: This data type is used for numeric values that have no fractions or values after a decimal place. It can store numbers ranging from approximately -2.147 billion to +2.147 billion. If you need to store numbers larger than this, you would need a different, larger “bucket”.
String: Used to store strings of individual characters. This can be a name like “Bob” or “Tabor”. The string “bucket” is considered “massive” compared to other data types. Strings are also described as “immutable,” meaning changes to a string behind the scenes involve creating new memory allocations.
Boolean: A small data type used to store true or false values (represented as 0 or 1).
Date: Allows you to work with dates and times. You can initialize a Date variable to a specific point in time (past, present using the Now function, or future) or parse it from a string.
Time Span: This is a data type that represents a span or duration of time, such as “three years,” “five years,” or “a thousand days,” rather than a specific date. You can perform calculations like adding or subtracting time spans.
Decimal: Used when dealing with monetary values. Unlike integers, it allows for values after the decimal place.
Declaring and Initializing Variables with Data Types
Variables are declared using the Dim keyword, followed by the variable name, the As keyword, and then the data type. For example: Dim x As Integer or Dim myFirstName As String.
Values are assigned to variables using the assignment operator (=). For example: x = 7 or myFirstName = console.readline().
You can also initialize a variable’s value at the point of declaration. This sets the variable to a “valid state” immediately. For example: Dim myFirstName As String = “Bob”.
Working with Data Types
Case Insensitivity: Visual Basic is case insensitive when it comes to variable names, meaning myFirstName and MyFirstName are treated as the same variable. You cannot declare the same variable twice, even with different casing.
Data Type Conversion: You often need to convert data from one type to another. Examples include CInt() to convert a string to an integer, or CStr() to convert a number to a string. While Visual Basic can be “forgiving” and sometimes perform automatic conversions, it’s recommended to be deliberate about type conversion using explicit methods to avoid potential problems.
Formatting: Data types like strings and dates can be formatted for display using replacement syntax within String.Format or Console.WriteLine. This allows for custom display of numbers (e.g., as currency or with commas) and dates (e.g., month name, short date string).
Custom Data Types (Classes)
Beyond the built-in data types, you can create your own custom data types using classes.
A class acts as a blueprint or a “cookie cutter” for creating objects. It allows you to group related properties (attributes) of different data types together into a single logical container.
For instance, a Car class could have properties like Make (String), Model (String), Year (Integer), and Color (String).
When you instantiate a class, you create an object, which is a distinct “bucket” in memory based on that class definition. For example, Dim myCar As New Car() creates an object (an instance) of the Car class, allowing you to set and retrieve its properties like myCar.Make = “Toyota”.

Visual Basic Code Organization and Best Practices

Code organization is a crucial aspect of developing applications in Visual Basic, providing structure and enhancing the readability and maintainability of your code. It involves arranging your code into logical units, which helps in managing complexity, reducing duplication, and facilitating teamwork.

Here are the key aspects of code organization discussed:

Fundamental Organizational Units: Modules and Classes
At a high level, your Visual Basic code is organized within code blocks. These blocks define containers for your code.
Modules are simple organizational tools, acting as containers for related methods (subroutines and functions).
Classes are also containers for methods, but they have a “special purpose” related to object-oriented programming. They serve as blueprints or “cookie cutters” for creating objects, allowing you to group related properties (attributes) and methods into a single logical container. For example, a Car class can define properties like Make, Model, Year, and Color that are applicable to every car.
Methods: The Building Blocks within Containers
A method (an umbrella term for subroutines and functions) is simply a block of code that is given a name.
Methods help to:
Better organize code.
Eliminate duplicate code and the need for copying and pasting, which can introduce bugs.
Encapsulate specific features, making them reusable across the application.
Simplify updates; changes made in one method benefit all places where that method is called.
The concept of a method signature (the number and data type of input parameters) allows for overloaded methods, where multiple versions of a method can exist with the same name but different input parameter configurations.
A useful guideline for method organization suggests that “no method should have more than six lines of code in it,” promoting tidy and readable code.
Classes and Objects: Blueprints and Instances
A class defines the blueprint for creating an object. It’s like a cookie cutter that defines the shape.
An object is an instance of a class. It’s the “cookie” created from the cookie cutter, a distinct “bucket” in the computer’s memory based on the class definition.
You instantiate a class using the New keyword, which brings an object to life in memory. Once instantiated, you can set and retrieve its properties, such as myCar.Make = “Toyota”.
Project and Solution Structure
Code files (like Module1.vb or Car.vb) are organized into projects.
Projects are then compiled into a .NET assembly.
One or more projects are organized into a solution, which acts as an overarching “umbrella”. While starting with one project per solution is common, more complex business applications often manage multiple related projects within the same solution for better code management.
The Solution Explorer in Visual Studio provides a tree-like view for navigating the files and settings within projects and solutions.
By default, projects are saved in your user’s Documents\Visual Studio\[Version]\Projects directory.
Principles for Readable and Maintainable Code
Human Readability: Strive to make your code “read as much like an English story as possible”.
Naming Conventions: Use descriptive names for variables and methods. Camel casing (e.g., myFirstName) is a common convention for local variables.
Indentation and Whitespace: While optional for execution, Visual Studio automatically indents code to denote containment and improve visual readability.
Color Coding: Visual Studio uses different colors for literal strings, classes, modules, and keywords to enhance code readability.
Comments: Use a single quote mark (‘) to add comments or to temporarily “comment out” lines of code, effectively deleting them without removing them from the source.
Line Continuation Character: The underscore (_) allows you to split a single logical line of code onto multiple physical lines, improving readability for very long statements.
Minimize Duplicate Code: Avoid copy-pasting segments of code; instead, encapsulate reusable logic within methods.
Be Deliberate with Types: Although Visual Basic is “forgiving” and might attempt automatic data type conversions, it’s recommended to be explicit about type conversions (e.g., using CInt(), CStr(), or ToString()) to avoid potential issues.

Visual Basic Tutorial for Beginners – Full Course

By Amjad Izhar
Contact: amjad.izhar@gmail.com
https://amjadizhar.blog

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Category: Visual Basic

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