C# WinForms - Multiselect not working on OpenFileDialog & Listbox

Question

Hey Everyone, Sorry to bother you with this, but I'm having an issue with selecting multiple xlsx files through a file browser window in a winforms application when debugging and can't figure out what I did wrong.

Problem: I set Multiselect=true under the OpenFileDialog but I still cannot select more than one file.

• What do I need to change to get the multiSelect feature to work?
• Do I need to add anything under sourceFileOpenFileDialog method?

• Do I need to add anything under listBoxSourceFiles_SelectedIndexChanged method to get the filenames to load correclty in the listbox?

  // When the user clicks on Select Files Button, this happens  
  private void sourceFiles_Click(object sender, EventArgs e)
  {
      Stream myStream;
      int i = 0;
      OpenFileDialog sourceFileOpenFileDialog = new OpenFileDialog();
  
      this.sourceFileOpenFileDialog.InitialDirectory = "i:\\CommissisionReconciliation\\Review\\";
      this.sourceFileOpenFileDialog.Filter = "Excel Files (*.xls;*.xlsx;)|*.xls;*.xlsx;|" + "All Files (*.*)|*.*";
      this.sourceFileOpenFileDialog.FilterIndex = 2;
      this.sourceFileOpenFileDialog.RestoreDirectory = true;
      this.sourceFileOpenFileDialog.Multiselect = true;
      this.sourceFileOpenFileDialog.Title = "Please Select Excel Source File(s) for Consolidation";
  
      if (sourceFileOpenFileDialog.ShowDialog() == DialogResult.OK)
      {
          try
          {
              if ((myStream = sourceFileOpenFileDialog.OpenFile()) != null)
              {
                  using (myStream)
                  {
                      foreach (string FileName in sourceFileOpenFileDialog.FileNames)
                      {
                          sourceFileOpenFileDialog.FileNames[i] = FileName;
                          listBoxSourceFiles.Items.Add(FileName);
                          Log("Source Files: " + sourceFileOpenFileDialog.FileNames[i]);
                          i++;
                      }
                  }
              }
  
          }
          catch (Exception ex)
          {
              MessageBox.Show("Error: Could not read file from disk. Original error: " + ex.Message);
          }
  }
  
  //method for the listbox. Do I need anything here? 
  private void listBoxSourceFiles_SelectedIndexChanged(object sender, EventArgs e)
  {
  
  }
  
  //method for the sourceFileOpenFileDialog.  Do I need anything here?
  private void sourceFileOpenFileDialog_FileOk(object sender, CancelEventArgs e)
  {
  
  }
  

I updated the code to reflect sourceFileOpenFileDialog and the MultiSelect or Title doesn't work... Perhaps I'm referencing the onfiledialog wrong? is this the proper prefix to use?

Thanks for looking!

Answer 1

You are using two OpenFileDialogs. You display sourceFilesList but you initialized sourceFileOpenFileDialog. Using consistent naming rules religiously is a great way to avoid bugs like these btw.

Next problem, what is OpenFile() supposed to do when you selected more than one file? What is myStream actually used for?