Option Explicit
Private Sub ListBox_Jugendliche_DblClick(ByVal Cancel As MSForms.ReturnBoolean)
Dim dateiname As String, pfad As String
Dim wbkBook As Workbook
pfad = ActiveWorkbook.Path
dateiname = pfad & "\Bewohner\" & ListBox_Jugendliche.Value & "\" & "Einzeldoku " & ListBox_Jugendliche.Value & ".xlsx"
If IsNull(ListBox_Jugendliche.Value) Then
MsgBox "Kein Jugendlicher ausgewählt"
Exit Sub
ElseIf Dir(dateiname) = "" Then
MsgBox "Datei nicht vorhanden"
Else
For Each wbkBook In Workbooks
If wbkBook.Name = "Einzeldoku " & ListBox_Jugendliche.Value & ".xlsx" Then Exit For
Next
If wbkBook Is Nothing Then
Call Workbooks.Open(Filename:=dateiname)
Else
Set wbkBook = Nothing
End If
End If
Unload Me
End Sub