If...Then...Else Statement

Defines one or more statement blocks that you only want to execute if a given condition or expression is True.

  If condition Then 
      statements
  [{ElseIf} condition Then
      statements]
  [Else 
      statements]
  {EndIf|End If}

Instead of End If you can write EndIf.

If statements can be shortened to one line when using single statement blocks.

  If condition Then statement [Else statement]

The If...Then statement executes program blocks depending on given conditions. When LibreOffice Basic encounters an If statement, the condition is tested. If the condition is True, all subsequent statements up to the next Else or ElseIf statement are executed. If the condition is False, and an ElseIf statement follows, LibreOffice Basic tests the next expression and executes the following statements if the condition is True. If False, the program continues either with the next ElseIf or Else statement. Statements following Else are executed only if none of the previously tested conditions were True. After all conditions are evaluated, and the corresponding statements executed, the program continues with the statement following EndIf.

Pode imbricar múltiplas instruções If...Then.

As instruções Else e ElseIf são opcionais.

Pode utilizar GoTo e GoSub para sair de um bloco If...Then, mas não para entrar numa estrutura If...Then.

O seguinte exemplo permite-lhe introduzir a data de validade de um produto, e determina se esta já foi ultrapassada.

Sub ExampleIfThenDate
    Dim sInput As String
    Dim dInput As Date
 
  On Error Goto inputError
    sInput = InputBox("Enter the expiration date (YYYY-MM-DD)")
    dInput = DateValue(sInput)
 
    If dInput < Date() Then
        MsgBox "A data de validade já passou"
    ElseIf dInput > Date() Then
        MsgBox "A data de validade ainda não passou"
    Else
        MsgBox "A data de validade termina hoje"
    End If
 
inputError:
    If dInput = 0 Then MsgBox "Invalid input"
End Sub