打开文件对话框并打开其他文件

Question

I am working on Opening a file(s). Requirement is, if user select Text in the filter, user can select mulitiple files. But if user selects any image files, user is allowed to select single file.

One way of doing is, capturing dialog.FileOk deleagate and intial checks.

Do we have any other ways of achiving the same.

Thank you,

Answer 1

OpenFileDialog does not provide events for FileSelected, or FilterChanged. So, with default OpenFileDialog you can only subscribe to FileOk event and cancel or accept it after user made selections. If you want to change settings on the fly (eg disabling multiple files selection when user choose images in filter) then you should extend OpenFileDialog . Unfortunately default one is sealed, thus you can't just inherit from that. So, take a look on these articles:

• Customizing OpenFileDialog in .NET
• Extend OpenFileDialog and SaveFileDialog the easy way

Answer 2

Use the following code:

private void button1_Click(object sender, System.EventArgs e)
{
    openFileDialog1.Filter = "Text Files (.txt)|*.txt|All Files (*.*)|*.*";
    openFileDialog1.FilterIndex = 1;

   if(openFileDialog1.ShowDialog() == DialogResult.OK)
   {
      System.IO.StreamReader sr = new 
         System.IO.StreamReader(openFileDialog1.FileName);
      MessageBox.Show(sr.ReadToEnd());
      sr.Close();
   }