private async void selectFileButton_Click(object sender, RoutedEventArgs e) { bool flag = false; AssignmentModel.SelectedAssignment = UserModel.SelectedAssignment; var picker = new Windows.Storage.Pickers.FileOpenPicker(); picker.ViewMode = Windows.Storage.Pickers.PickerViewMode.Thumbnail; picker.SuggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.PicturesLibrary; picker.FileTypeFilter.Add(".zip"); Windows.Storage.StorageFile file = await picker.PickSingleFileAsync(); if (file != null) { var temp = file; using (IRandomAccessStream fileStream = await file.OpenAsync(Windows.Storage.FileAccessMode.Read)) { flag = await AssignmentModel.submitAssignments(temp); } } if (flag) { var i = new Windows.UI.Popups.MessageDialog("上传成功!").ShowAsync(); } }