Conditional Statements (If, Select/Case)

If statement

If/Then/Else statement is used to execute code conditionally. The Else part can be omit. Here some examples:

If X > 0 Then

  MsgBox("X is positive")

End If

If S <> "" Then

  MsgBox("S is not empty")

Else

  MsgBox("S is empty")

End If

If S <> "" Then

  MsgBox("S is not empty")

  Return True

Else

  MsgBox("S is empty")

End If

If statement has also a shorter single-line version, that should be written without End If:

If X > 0 Then MsgBox("X is positive")

If X > 0 Then MsgBox("X is positive") Else MsgBox("X is negative or zero")

Select/Case statement

The Select statement is another statement for conditional code execution. Unlike MS VbScript, in NativeVB you can specify any expressions in case labels, not only constant literals. Also, NativeVB does not check values uniqueness. Just as in If statement, Else part can be omit. Examples:

Select Case x

  Case 0: 

    MsgBox("Zero")

  Case 1, 3, 5, 7, 9:

    MsgBox("Odd")

  Case 2, 4, 6, 8, 10:

    MsgBox("Even")

  Case Else

    MsgBox("I'm too young to know numbers greater than 10")

End Select

The Case Else label, if present, should be the last label in the Select statement. Since any expressions in case labels are allowed, you can also specify, for example, string expressions:

Select Case s

  Case "True":  

    b := True;

  Case "False": 

    b := False;

  Case Else

    MgsBox("Invalid value");

End Select