Programming Excel with VBA and .NET

Conditional Statements

One of the fundamental elements of programming is making decisions based on inputs. Visual Basic provides the If statement for making either/or decisions and the Select statement for making multiple-choice decisions. These two statements form the core of any logic your program uses to adjust to different conditions, and for that reason they are called conditional statements .

The If statement has several different forms:

• A very simple one-line form:

      If IsArray(Selection) Then MsgBox "Multiple cells selected."

• A block form that can contain multiple lines and alternative actions:

      Dim str As String
      If IsArray(Selection) Then
          str = "Grand total: " & _
            WorksheetFunction.Sum(Selection)
      Else
          str = "Please select more than one cell"
      End If
      MsgBox str

• A block form with multiple conditions and alternate actions:

      If IsArray(Selection) Then
          str = "Grand total: " & _
            WorksheetFunction.Sum(Selection)
      ElseIf TypeName(ActiveSheet) = "Worksheet" Then
          str = "Worksheet total: " & _
            WorksheetFunction.Sum(ActiveSheet.UsedRange)
      Else
          str = "Please select a worksheet"
      End If
      MsgBox str

You can have multiple ElseIf statements within an If block as shown by the following general form:

    If condition Then
        ' Do something
    [ElseIf condition Then
        ' Do something else]
    [ElseIf condition Then
        ' Can repeat ElseIf]
    [Else
        ' Do something else]
    End If

For more complex logic, you can include If statements within an enclosing If statement, or you can use the Select Case statement. The following ...