//=========================================================================== //==============================UI Methoden================================== //=========================================================================== private void BT_Load_Excel(object sender, RoutedEventArgs e) { OpenFileDialog fileDialog = new OpenFileDialog(); fileDialog.Filter = "Excel Datei|*.xlsx"; Nullable <bool> result = fileDialog.ShowDialog(); if (result == true) { loader = new LoadManager(LoadManager.DataType.Excel, fileDialog.FileName, ExcelCallback); loader.FinishedLoadingEvent += new EventHandler(LoadEventHandler); loader.LoadData(); } else { //Fehlermeldung implementieren } }