Optional (Visual Basic)

Specifies that a procedure argument can be omitted when the procedure is called.

Remarks

You must specify a default value for all optional procedure arguments.

The Optional modifier can be used in these contexts:

• Declare Statement

• Function Statement

• Property Statement

• Sub Statement

The following example defines a procedure that has an optional argument.

Public Function FindMatches(ByRef values As List(Of String),
                            ByVal searchString As String,
                            Optional ByVal matchCase As Boolean = False) As List(Of String)

    Dim results As IEnumerable(Of String)

    If matchCase Then
        results = From v In values
                  Where v.Contains(searchString)
    Else
        results = From v In values
                  Where UCase(v).Contains(UCase(searchString))
    End If

    Return results.ToList()
End Function

See Also

Other Resources

Keywords (Visual Basic)