If...Then...Else...End If Statement in VB6 - Sample Program 1

Visual Basic program application usually use If..Then..Else..End If statement. In this posting I would like to write a sample of simple program in VB6 which use If..Then..Else..End If statement with 2 conditions or more.
The syntax of the statement is the following:

With 2 conditions:

If Condition-1 Then
    Statement-1
Else
    Statement-2
End If

With more than 2 conditions:

If Condition-1 Then
    Statement-1
Else
    If Condition-2 Then    
        Statement-2
    Else
        If Condition-3 Then
            Statement-3
        Else
            Statement-4
        End If
    End If     
End If

Note: If the conditions are too much it is not effective if using If..Then..Else..End If statement, however it is better using Select Case..End Select statement.
The scenario of the program is as below:

This is a part of Registration Form that accept the Name and Gender information

The first data should be filled in is a Name

The next data is a gender code

The value that can be filled are just M and F (M for Male, and F for Female)

If user input another M and F a message appears on screen

When user input M for the Gender cell program will automatically display "Male", and when user input F for the Gender a word "Female" will be displayed automatically

After both Name and Gender cell filled with valid data, command button "Register" will Enable

When user click command button "Register" a greeting will appear on the screen
Your program coding will look like the folling list:

Private Sub cmdRegister_Click()
    'recheck data validity
    If txtName.Text = "" Then
        MsgBox "You must fill in the Name first"
        Exit Sub
    End If
    If txtGender.Text = "" Then
        MsgBox "You must fill in the Gender code"
        Exit Sub
    End If
    If txtGender.Text <> "M" And txtGender.Text <> "F" Then
        MsgBox "Just 'M' or 'F' for the Gender code "
        Exit Sub
    End If
    'display greeting
    lblGreeting.Caption = "Welcome " & IIf(txtGender.Text = "M", "Mr. ", "Mrs. ") & _
    Trim(txtName.Text) & ". Thank you for joining our club."
End Sub

Private Sub Form_Load()
   lblGender.Caption = ""
   lblGreeting.Caption = ""
End Sub

Private Sub txtGender_Change()
    If txtGender.Text <> "M" And txtGender.Text <> "F" Then
        MsgBox "Invalid value, you should fill in 'M' or 'F'"
    Else
        If txtGender.Text = "M" Then
            lblGender.Caption = "Male"
        Else
            lblGender.Caption = "Female"
        End If
    End If
    
    If txtName.Text <> "" Then
       cmdRegister.Enabled = True
    Else
       cmdRegister.Enabled = False
    End If
End Sub

Private Sub txtName_Change()
    If txtName.Text = "" Then
        cmdRegister.Enabled = False
    Else
        If txtGender.Text = "" Then
            cmdRegister.Enabled = False
        Else
            cmdRegister.Enabled = True
        End If
    End If
End Sub

Please look at below screen shot as your illustration:

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