System.IO.Stream myStream;
      OpenFileDialog thisDialog = new OpenFileDialog();

      thisDialog.InitialDirectory = "d:\\";
      thisDialog.Filter = "rcc files (*.rcc)|*.rcc|All files (*.*)|*.*";
      thisDialog.FilterIndex = 2;
      thisDialog.RestoreDirectory = true;
      thisDialog.Multiselect = true;
      thisDialog.Title = "Please Select Source File(s) for Conversion";

      if (thisDialog.ShowDialog() == DialogResult.OK)
      {
        foreach (String file in thisDialog.FileNames) 
        {
          try
          {
            if ((myStream = thisDialog.OpenFile()) != null)
            {
              using (myStream)
              {
                listBox1.Items.Add(file);
              }
            }
          }

          catch (Exception ex)
          {
            MessageBox.Show("Error: Could not read file from disk. Original error: " + ex.Message);
          }
        }
      }   

خیلی ممنون...کدا خیلی کامل بود