Programming Language

Visual Basic

Overview

Visual Basic is an event-driven programming language developed by Microsoft, widely used for Windows GUI application development.

Details

Visual Basic is an event-driven programming language announced by Microsoft in 1991. Based on the BASIC language, it provided a visual programming environment (RAD: Rapid Application Development) designed for efficient development of Windows GUI applications. With drag-and-drop user interface design, intuitive syntax, and rich control libraries, even programming beginners could create Windows applications relatively easily. Visual Basic 6.0 (VB6) was the last classic version, which then evolved into VB.NET based on the .NET Framework. Currently, maintenance of legacy systems is more central than new development, but it continues to operate in many enterprise systems.

Usage Examples

Hello World

' Classic Visual Basic (VB6) example
' Click event for a command button placed on a form
Private Sub Command1_Click()
    MsgBox "Hello, World!"
End Sub

' Execution in Immediate Window
' (Can be executed in VB Editor's Immediate Window)
Sub HelloWorldImmediate()
    Debug.Print "Hello, World!"
End Sub

' Defined as a procedure
Public Sub HelloWorld()
    MsgBox "Hello, World!", vbInformation, "Greeting"
End Sub

' Execution in Form Load event
Private Sub Form_Load()
    Me.Caption = "Hello, World! Application"
    Label1.Caption = "Hello, Visual Basic!"
End Sub

' Multi-line message
Private Sub ShowMultiLineMessage()
    Dim message As String
    message = "Hello, World!" & vbCrLf & _
              "Welcome to Visual Basic!" & vbCrLf & _
              "GUI application development is easy."
    MsgBox message, vbInformation, "Multi-line Message"
End Sub

' Console application style example (actually using textbox on form)
Private Sub ConsoleStyleHello()
    Text1.Text = Text1.Text & "Hello, World!" & vbCrLf
    Text1.Text = Text1.Text & "Current time: " & Now() & vbCrLf
    Text1.Text = Text1.Text & "Created with Visual Basic" & vbCrLf
End Sub

' Example using input dialog
Private Sub InteractiveHello()
    Dim userName As String
    userName = InputBox("Please enter your name:", "Name Input", "Guest")
    
    If userName <> "" Then
        MsgBox "Hello, " & userName & "!", vbInformation, "Personal Greeting"
    Else
        MsgBox "No name was entered.", vbExclamation, "Warning"
    End If
End Sub

' Example using loops
Private Sub RepeatedHello()
    Dim i As Integer
    Dim message As String
    
    For i = 1 To 5
        message = message & "Hello " & i & " times!" & vbCrLf
    Next i
    
    MsgBox message, vbInformation, "Repeated Greeting"
End Sub

Variables and Data Types

' Basic variable declaration
Private Sub VariableBasics()
    ' Basic data types
    Dim studentName As String
    Dim age As Integer
    Dim height As Single
    Dim weight As Double
    Dim isActive As Boolean
    Dim birthDate As Date
    
    ' Value assignment
    studentName = "John Doe"
    age = 25
    height = 175.5
    weight = 68.5
    isActive = True
    birthDate = #12/25/1998#
    
    ' Declaration with initialization
    Dim score As Integer = 85
    Dim grade As String = "A"
    
    ' Display results
    Debug.Print "Name: " & studentName
    Debug.Print "Age: " & age
    Debug.Print "Height: " & height & "cm"
    Debug.Print "Weight: " & weight & "kg"
    Debug.Print "Active: " & isActive
    Debug.Print "Birth Date: " & birthDate
    Debug.Print "Score: " & score
    Debug.Print "Grade: " & grade
End Sub

' Numeric data type details
Private Sub NumericTypes()
    ' Integer types
    Dim byteValue As Byte        ' 0-255
    Dim integerValue As Integer  ' -32,768 to 32,767
    Dim longValue As Long        ' -2,147,483,648 to 2,147,483,647
    
    ' Floating point types
    Dim singleValue As Single    ' Single precision floating point
    Dim doubleValue As Double    ' Double precision floating point
    
    ' Currency type
    Dim currencyValue As Currency ' Fixed-point numeric (for currency calculations)
    
    ' Value assignment
    byteValue = 255
    integerValue = -12345
    longValue = 1234567890
    singleValue = 3.14159
    doubleValue = 3.141592653589793
    currencyValue = 1234.56
    
    ' Display
    Debug.Print "Byte: " & byteValue
    Debug.Print "Integer: " & integerValue
    Debug.Print "Long: " & longValue
    Debug.Print "Single: " & singleValue
    Debug.Print "Double: " & doubleValue
    Debug.Print "Currency: " & Format(currencyValue, "Currency")
End Sub

' String operations
Private Sub StringOperations()
    Dim firstName As String
    Dim lastName As String
    Dim fullName As String
    Dim message As String
    
    firstName = "John"
    lastName = "Smith"
    
    ' String concatenation
    fullName = lastName & " " & firstName
    
    ' Using string functions
    Debug.Print "Full Name: " & fullName
    Debug.Print "Length: " & Len(fullName)
    Debug.Print "Uppercase: " & UCase(fullName)
    Debug.Print "Lowercase: " & LCase(fullName)
    Debug.Print "Left 3 chars: " & Left(fullName, 3)
    Debug.Print "Right 2 chars: " & Right(fullName, 2)
    Debug.Print "2 chars from position 3: " & Mid(fullName, 3, 2)
    
    ' String search
    If InStr(fullName, "Smith") > 0 Then
        Debug.Print "Last name is Smith"
    End If
    
    ' String replacement
    message = Replace(fullName, "Smith", "Johnson")
    Debug.Print "After replacement: " & message
End Sub

' Array usage
Private Sub ArrayExamples()
    ' Static arrays
    Dim numbers(1 To 5) As Integer
    Dim fruits(3) As String  ' 0 to 3 (4 elements)
    
    ' Value assignment
    numbers(1) = 10
    numbers(2) = 20
    numbers(3) = 30
    numbers(4) = 40
    numbers(5) = 50
    
    fruits(0) = "apple"
    fruits(1) = "banana"
    fruits(2) = "orange"
    fruits(3) = "strawberry"
    
    ' Dynamic arrays
    Dim scores() As Integer
    ReDim scores(1 To 10)  ' Dynamically set size
    
    ' Set array values
    Dim i As Integer
    For i = 1 To 10
        scores(i) = i * 10
    Next i
    
    ' Display array contents
    Debug.Print "=== Numeric Array ==="
    For i = 1 To 5
        Debug.Print "numbers(" & i & ") = " & numbers(i)
    Next i
    
    Debug.Print "=== String Array ==="
    For i = 0 To 3
        Debug.Print "fruits(" & i & ") = " & fruits(i)
    Next i
    
    Debug.Print "=== Dynamic Array ==="
    For i = 1 To 10
        Debug.Print "scores(" & i & ") = " & scores(i)
    Next i
    
    ' Resize array (preserve data)
    ReDim Preserve scores(1 To 15)
    
    ' Set values for new elements
    For i = 11 To 15
        scores(i) = i * 5
    Next i
End Sub

' Variant data type
Private Sub VariantType()
    Dim varValue As Variant
    
    ' Store various type values
    varValue = "string"
    Debug.Print "As string: " & varValue & " (Type: " & TypeName(varValue) & ")"
    
    varValue = 12345
    Debug.Print "As number: " & varValue & " (Type: " & TypeName(varValue) & ")"
    
    varValue = #12/25/2023#
    Debug.Print "As date: " & varValue & " (Type: " & TypeName(varValue) & ")"
    
    varValue = True
    Debug.Print "As boolean: " & varValue & " (Type: " & TypeName(varValue) & ")"
    
    ' Can also store arrays
    Dim tempArray(2) As String
    tempArray(0) = "A"
    tempArray(1) = "B"
    tempArray(2) = "C"
    varValue = tempArray
    Debug.Print "As array: " & Join(varValue, ",") & " (Type: " & TypeName(varValue) & ")"
End Sub

' Using constants
Private Sub ConstantExamples()
    ' Constant declaration
    Const PI As Double = 3.14159265359
    Const COMPANY_NAME As String = "Sample Corporation"
    Const MAX_USERS As Integer = 100
    
    ' Usage example
    Dim radius As Double
    Dim area As Double
    
    radius = 5
    area = PI * radius * radius
    
    Debug.Print "Circle radius: " & radius
    Debug.Print "Circle area: " & area
    Debug.Print "Company name: " & COMPANY_NAME
    Debug.Print "Maximum users: " & MAX_USERS
End Sub

Control Structures and Functions

' If statements and Select Case statements
Private Sub ConditionalStatements()
    Dim score As Integer
    Dim grade As String
    
    score = 85
    
    ' If-ElseIf-Else statement
    If score >= 90 Then
        grade = "A"
    ElseIf score >= 80 Then
        grade = "B"
    ElseIf score >= 70 Then
        grade = "C"
    ElseIf score >= 60 Then
        grade = "D"
    Else
        grade = "F"
    End If
    
    Debug.Print "Score: " & score & ", Grade: " & grade
    
    ' Select Case statement
    Select Case score
        Case 90 To 100
            Debug.Print "Excellent"
        Case 80 To 89
            Debug.Print "Good"
        Case 70 To 79
            Debug.Print "Average"
        Case 60 To 69
            Debug.Print "Needs Improvement"
        Case Else
            Debug.Print "Failed"
    End Select
    
    ' Select Case with multiple values
    Dim dayOfWeek As Integer
    dayOfWeek = Weekday(Now)
    
    Select Case dayOfWeek
        Case 1, 7  ' Sunday, Saturday
            Debug.Print "It's weekend"
        Case 2 To 6  ' Monday to Friday
            Debug.Print "It's weekday"
    End Select
End Sub

' Loop structures
Private Sub LoopStructures()
    Dim i As Integer
    Dim j As Integer
    Dim total As Integer
    
    Debug.Print "=== For Next Loop ==="
    For i = 1 To 5
        Debug.Print "Count: " & i
    Next i
    
    Debug.Print "=== For Loop with Step ==="
    For i = 10 To 2 Step -2
        Debug.Print "Reverse: " & i
    Next i
    
    Debug.Print "=== Do While Loop ==="
    i = 1
    Do While i <= 3
        Debug.Print "Do While: " & i
        i = i + 1
    Loop
    
    Debug.Print "=== Do Until Loop ==="
    i = 1
    Do Until i > 3
        Debug.Print "Do Until: " & i
        i = i + 1
    Loop
    
    Debug.Print "=== While Wend Loop ==="
    i = 1
    While i <= 3
        Debug.Print "While Wend: " & i
        i = i + 1
    Wend
    
    Debug.Print "=== Nested Loops ==="
    For i = 1 To 3
        For j = 1 To 2
            Debug.Print "Outer:" & i & ", Inner:" & j
        Next j
    Next i
    
    Debug.Print "=== Using Exit Statement ==="
    For i = 1 To 10
        If i = 5 Then
            Debug.Print "Exit at 5"
            Exit For
        End If
        Debug.Print "Value: " & i
    Next i
End Sub

' Functions and sub procedures
Private Sub ProcedureExamples()
    Dim result As Double
    Dim message As String
    
    ' Function calls
    result = CalculateArea(5)
    Debug.Print "Area of circle with radius 5: " & result
    
    result = AddNumbers(10, 20)
    Debug.Print "10 + 20 = " & result
    
    ' Sub procedure calls
    DisplayMessage "Hello"
    
    ' Pass by reference example
    Dim value1 As Integer
    Dim value2 As Integer
    value1 = 10
    value2 = 20
    
    Debug.Print "Before swap: value1=" & value1 & ", value2=" & value2
    SwapValues value1, value2
    Debug.Print "After swap: value1=" & value1 & ", value2=" & value2
    
    ' Optional argument example
    message = CreateGreeting("Smith")
    Debug.Print message
    
    message = CreateGreeting("Johnson", " Jr.")
    Debug.Print message
End Sub

' Area calculation function
Private Function CalculateArea(radius As Double) As Double
    Const PI As Double = 3.14159265359
    CalculateArea = PI * radius * radius
End Function

' Addition function
Private Function AddNumbers(num1 As Double, num2 As Double) As Double
    AddNumbers = num1 + num2
End Function

' Message display sub procedure
Private Sub DisplayMessage(msg As String)
    Debug.Print "Message: " & msg
End Sub

' Value swapping (pass by reference)
Private Sub SwapValues(ByRef a As Integer, ByRef b As Integer)
    Dim temp As Integer
    temp = a
    a = b
    b = temp
End Sub

' Function with optional arguments
Private Function CreateGreeting(name As String, Optional suffix As String = " Sir/Madam") As String
    CreateGreeting = "Hello, " & name & suffix
End Function

' Variable argument example (using array)
Private Function SumArray(numbers() As Integer) As Long
    Dim i As Integer
    Dim total As Long
    
    total = 0
    For i = LBound(numbers) To UBound(numbers)
        total = total + numbers(i)
    Next i
    
    SumArray = total
End Function

' Error handling
Private Sub ErrorHandlingExample()
    On Error GoTo ErrorHandler
    
    Dim result As Double
    Dim num1 As Double
    Dim num2 As Double
    
    num1 = 10
    num2 = 0
    
    Debug.Print "Performing division: " & num1 & " ÷ " & num2
    result = num1 / num2  ' Division by zero error occurs
    Debug.Print "Result: " & result
    
    Exit Sub

ErrorHandler:
    Debug.Print "Error occurred: " & Err.Description
    Debug.Print "Error number: " & Err.Number
    
    ' Resume from error
    If Err.Number = 11 Then  ' Division error
        Debug.Print "Division by zero error detected"
        result = 0
        Resume Next
    Else
        Debug.Print "Unexpected error"
        Resume ExitPoint
    End If

ExitPoint:
    Debug.Print "Exiting procedure"
End Sub

Object-Oriented Programming and GUI Operations

' Class module example (separate file: Person.cls)
' Class: Person
' Class with properties and methods

'Private mName As String
'Private mAge As Integer
'Private mEmail As String

' Property (Name)
'Public Property Get Name() As String
'    Name = mName
'End Property

'Public Property Let Name(value As String)
'    mName = value
'End Property

' Property (Age)
'Public Property Get Age() As Integer
'    Age = mAge
'End Property

'Public Property Let Age(value As Integer)
'    If value >= 0 And value <= 150 Then
'        mAge = value
'    Else
'        Err.Raise 9999, "Person", "Age must be between 0 and 150"
'    End If
'End Property

' Property (Email)
'Public Property Get Email() As String
'    Email = mEmail
'End Property

'Public Property Let Email(value As String)
'    mEmail = value
'End Property

' Methods
'Public Function Introduce() As String
'    Introduce = "My name is " & mName & " and I am " & mAge & " years old."
'End Function

'Public Sub HaveBirthday()
'    mAge = mAge + 1
'End Sub

' Class usage example in form
Private Sub ClassUsageExample()
    ' Create Person class instance
    ' Dim person As New Person
    
    ' Set properties
    ' person.Name = "John Doe"
    ' person.Age = 25
    ' person.Email = "[email protected]"
    
    ' Call methods
    ' Debug.Print person.Introduce()
    ' person.HaveBirthday()
    ' Debug.Print "Age after birthday: " & person.Age
    
    Debug.Print "Class example (commented out)"
End Sub

' Form control operations
Private Sub FormControlExamples()
    ' Text box operations
    Text1.Text = "Hello, Visual Basic!"
    Text1.ForeColor = vbRed
    Text1.BackColor = vbYellow
    Text1.Font.Size = 12
    Text1.Font.Bold = True
    
    ' Label operations
    Label1.Caption = "Current time: " & Format(Now, "yyyy/mm/dd hh:nn:ss")
    Label1.ForeColor = vbBlue
    
    ' Command button operations
    Command1.Caption = "Click me"
    Command1.Enabled = True
    
    ' List box operations
    List1.Clear
    List1.AddItem "Item 1"
    List1.AddItem "Item 2"
    List1.AddItem "Item 3"
    List1.ListIndex = 0  ' Select first item
    
    ' Combo box operations
    Combo1.Clear
    Combo1.AddItem "Option A"
    Combo1.AddItem "Option B"
    Combo1.AddItem "Option C"
    Combo1.Text = "Please select"
    
    ' Check box
    Check1.Caption = "I agree"
    Check1.Value = vbChecked
    
    ' Option buttons
    Option1.Caption = "Male"
    Option2.Caption = "Female"
    Option1.Value = True
    
    ' Picture box
    Picture1.BackColor = vbCyan
    Picture1.BorderStyle = 1  ' With border
    
    ' Frame
    Frame1.Caption = "Options"
End Sub

' Event procedure examples
Private Sub Command1_Click()
    MsgBox "Button was clicked!", vbInformation, "Event"
End Sub

Private Sub Text1_Change()
    ' Processing when text is changed
    Label2.Caption = "Character count: " & Len(Text1.Text)
End Sub

Private Sub List1_Click()
    ' Processing when list box item is clicked
    If List1.ListIndex >= 0 Then
        Text2.Text = "Selected item: " & List1.List(List1.ListIndex)
    End If
End Sub

Private Sub Form_Load()
    ' Processing when form is loaded
    Me.Caption = "Visual Basic Sample"
    Me.BackColor = vbButtonFace
    
    ' Initialization
    FormControlExamples
End Sub

Private Sub Form_Resize()
    ' Processing when form size is changed
    If Me.WindowState <> vbMinimized Then
        ' Control size adjustment, etc.
        Text1.Width = Me.ScaleWidth - 200
    End If
End Sub

' Menu event examples
Private Sub mnuFileOpen_Click()
    ' File→Open menu processing
    CommonDialog1.Filter = "Text Files (*.txt)|*.txt|All Files (*.*)|*.*"
    CommonDialog1.ShowOpen
    
    If CommonDialog1.filename <> "" Then
        ' File opening processing
        Text1.Text = ""
        Open CommonDialog1.filename For Input As #1
        Do Until EOF(1)
            Text1.Text = Text1.Text & Input(1, 1)
        Loop
        Close #1
    End If
End Sub

Private Sub mnuFileSave_Click()
    ' File→Save menu processing
    CommonDialog1.Filter = "Text Files (*.txt)|*.txt"
    CommonDialog1.ShowSave
    
    If CommonDialog1.filename <> "" Then
        ' File saving processing
        Open CommonDialog1.filename For Output As #1
        Print #1, Text1.Text
        Close #1
        MsgBox "File saved", vbInformation
    End If
End Sub

Database Operations and File Processing

' File operation examples
Private Sub FileOperations()
    Dim filename As String
    Dim fileContent As String
    Dim lineContent As String
    
    filename = "C:\temp\sample.txt"
    
    ' Write to file
    Open filename For Output As #1
    Print #1, "Visual Basic text file"
    Print #1, "Second line content"
    Print #1, "Third line content"
    Print #1, "Current time: " & Now()
    Close #1
    
    Debug.Print "File created: " & filename
    
    ' Read from file (all at once)
    Open filename For Input As #1
    fileContent = ""
    Do Until EOF(1)
        Line Input #1, lineContent
        fileContent = fileContent & lineContent & vbCrLf
    Loop
    Close #1
    
    Debug.Print "=== File Content ==="
    Debug.Print fileContent
    
    ' Read from file (line by line)
    Open filename For Input As #1
    Dim lineNumber As Integer
    lineNumber = 1
    Do Until EOF(1)
        Line Input #1, lineContent
        Debug.Print "Line" & lineNumber & ": " & lineContent
        lineNumber = lineNumber + 1
    Loop
    Close #1
    
    ' Binary file operation example
    Dim binaryFile As String
    Dim byteData As Byte
    
    binaryFile = "C:\temp\binary.dat"
    
    ' Binary write
    Open binaryFile For Binary As #1
    For i = 1 To 10
        Put #1, , CByte(i * 10)
    Next i
    Close #1
    
    ' Binary read
    Open binaryFile For Binary As #1
    Debug.Print "=== Binary Data ==="
    For i = 1 To LOF(1)
        Get #1, i, byteData
        Debug.Print "Position" & i & ": " & byteData
    Next i
    Close #1
End Sub

' INI file operations
Private Declare Function GetPrivateProfileString Lib "kernel32" Alias "GetPrivateProfileStringA" _
    (ByVal lpApplicationName As String, ByVal lpKeyName As String, ByVal lpDefault As String, _
     ByVal lpReturnedString As String, ByVal nSize As Long, ByVal lpFileName As String) As Long

Private Declare Function WritePrivateProfileString Lib "kernel32" Alias "WritePrivateProfileStringA" _
    (ByVal lpApplicationName As String, ByVal lpKeyName As String, ByVal lpString As String, _
     ByVal lpFileName As String) As Long

Private Sub INIFileOperations()
    Dim iniFile As String
    Dim buffer As String
    Dim result As Long
    
    iniFile = App.Path & "\config.ini"
    
    ' Write to INI file
    result = WritePrivateProfileString("Settings", "UserName", "John Doe", iniFile)
    result = WritePrivateProfileString("Settings", "Language", "English", iniFile)
    result = WritePrivateProfileString("Database", "Server", "localhost", iniFile)
    result = WritePrivateProfileString("Database", "Port", "3306", iniFile)
    
    Debug.Print "INI file created: " & iniFile
    
    ' Read from INI file
    buffer = Space(255)
    result = GetPrivateProfileString("Settings", "UserName", "", buffer, 255, iniFile)
    Debug.Print "User name: " & Left(buffer, result)
    
    buffer = Space(255)
    result = GetPrivateProfileString("Settings", "Language", "", buffer, 255, iniFile)
    Debug.Print "Language: " & Left(buffer, result)
    
    buffer = Space(255)
    result = GetPrivateProfileString("Database", "Server", "", buffer, 255, iniFile)
    Debug.Print "Server: " & Left(buffer, result)
End Sub

' CSV file operations
Private Sub CSVOperations()
    Dim csvFile As String
    Dim csvLine As String
    Dim fields() As String
    Dim i As Integer
    
    csvFile = "C:\temp\data.csv"
    
    ' Write to CSV file
    Open csvFile For Output As #1
    Print #1, "Name,Age,Department,Salary"
    Print #1, "John Doe,25,Sales,300000"
    Print #1, "Jane Smith,30,Development,400000"
    Print #1, "Bob Johnson,35,Management,350000"
    Close #1
    
    Debug.Print "CSV file created: " & csvFile
    
    ' Read from CSV file
    Open csvFile For Input As #1
    
    ' Read header row
    Line Input #1, csvLine
    Debug.Print "=== Header ==="
    Debug.Print csvLine
    
    Debug.Print "=== Data ==="
    Do Until EOF(1)
        Line Input #1, csvLine
        fields = Split(csvLine, ",")
        
        Debug.Print "Name: " & fields(0)
        Debug.Print "Age: " & fields(1)
        Debug.Print "Department: " & fields(2)
        Debug.Print "Salary: " & Format(fields(3), "#,##0")
        Debug.Print "---"
    Loop
    
    Close #1
End Sub

' Registry operations
Private Sub RegistryOperations()
    Dim keyPath As String
    Dim value As String
    
    keyPath = "HKEY_CURRENT_USER\Software\MyApp"
    
    ' Save values to registry
    SaveSetting "MyApp", "Settings", "UserName", "John Doe"
    SaveSetting "MyApp", "Settings", "LastLogin", CStr(Now())
    SaveSetting "MyApp", "Window", "Width", "800"
    SaveSetting "MyApp", "Window", "Height", "600"
    
    Debug.Print "Settings saved to registry"
    
    ' Read values from registry
    value = GetSetting("MyApp", "Settings", "UserName", "")
    Debug.Print "User name: " & value
    
    value = GetSetting("MyApp", "Settings", "LastLogin", "")
    Debug.Print "Last login: " & value
    
    value = GetSetting("MyApp", "Window", "Width", "640")
    Debug.Print "Window width: " & value
    
    value = GetSetting("MyApp", "Window", "Height", "480")
    Debug.Print "Window height: " & value
    
    ' Delete settings from registry
    ' DeleteSetting "MyApp", "Settings", "UserName"
    ' DeleteSetting "MyApp"  ' Delete entire application settings
End Sub

' Simple database operations (DAO/ADO)
Private Sub DatabaseOperations()
    ' This example uses Access database
    ' Actual implementation requires reference settings:
    ' Microsoft DAO 3.6 Object Library or
    ' Microsoft ActiveX Data Objects Library
    
    Debug.Print "Database operation example (requires reference settings for implementation)"
    
    ' DAO example (commented out)
    'Dim db As Database
    'Dim rs As Recordset
    'Dim sql As String
    
    ' Open database
    'Set db = OpenDatabase("C:\temp\sample.mdb")
    
    ' Execute SELECT query
    'sql = "SELECT * FROM Users"
    'Set rs = db.OpenRecordset(sql)
    
    ' Read records
    'Do Until rs.EOF
    '    Debug.Print rs!UserName & ", " & rs!Age
    '    rs.MoveNext
    'Loop
    
    ' Release resources
    'rs.Close
    'db.Close
    'Set rs = Nothing
    'Set db = Nothing
End Sub

Advantages and Disadvantages

Advantages

• Visual Development Environment: Easy GUI creation with drag-and-drop
• Easy-to-learn Syntax: BASIC language base, understandable for beginners
• Rich Controls: Abundant Windows standard UI components
• RAD (Rapid Application Development): Quick development from prototype to practical applications
• Event-driven Programming: Intuitive programming model
• Windows Compatibility: Easy integration with Windows API and various components

Disadvantages

• Legacy Technology: Decreasing adoption for new development
• Platform Limitation: Dependent on Windows platform
• Performance: Execution speed inferior to other languages even when compiled
• Lack of Modern Features: Limited object-oriented capabilities
• Future Concerns: Microsoft's end of support and recommendation to migrate to VB.NET
• Memory Management: Manual resource management required in some scenarios

Reference Links

Official Documentation

• Visual Basic 6.0 Documentation - Microsoft official documentation
• VB.NET Documentation - VB.NET migration information

Learning Resources

• Planet Source Code VB6 - Code sample collection
• VB Helper - Tutorials and samples
• VBForums - Community forums

Development Tools & Environment

• Visual Basic 6.0 - Development environment (archived)
• VB.NET - Successor Visual Studio
• VBA - VBA for Office

Migration & Alternative Technologies

• VB.NET Migration Guide - VB.NET migration guide
• C# for VB Developers - Migration information to C#