C# .NET - multiple selection

This link provides a nice example.

http://msdn.microsoft.com/en-us/library/cc148994.aspx

Here is a snippet

// To copy all the files in one directory to another directory. 
// Get the files in the source folder. (To recursively iterate through 
// all subfolders under the current directory, see 
// "How to: Iterate Through a Directory Tree.") 
// Note: Check for target path 
if (System.IO.Directory.Exists(sourcePath)) 
{ 
  string[] files = System.IO.Directory.GetFiles(sourcePath); 
 
  // Copy the files and overwrite destination files if they already exist. 
  foreach (string s in files) 
  { 
    // Use static Path methods to extract only the file name from the path. 
    fileName = System.IO.Path.GetFileName(s); 
    destFile = System.IO.Path.Combine(targetPath, fileName); 
    System.IO.File.Copy(s, destFile, true); 
  } 
} 

For openfiledialog you are using the multiselection, but for the folderBrowseDialog there is not option for multiselect.

So you have to use the loop to move all the selected files

private void button2_Click(object sender, EventArgs e)
{
  OpenFileDialog f = new OpenFileDialog();
  f.Title = "select file to copy";
  f.Multiselect = true;
  if (f.ShowDialog() == System.Windows.Forms.DialogResult.OK)
  {
    FolderBrowserDialog b1 = new FolderBrowserDialog();
    if (b1.ShowDialog() == System.Windows.Forms.DialogResult.OK)
    {
      foreach (string file in f.FileNames)
      {
        string CopyTo = file;
        string FileName = b1.SelectedPath + "//" + Path.GetFileName(f.FileName);
        //Check if file exist
        if (File.Exists(FileName))
        {
          // if exist then rename it..
          string PasteTo = b1.SelectedPath + "//" + "(1)" + Path.GetFileName(FileName);
          File.Copy(CopyTo, PasteTo);
          MessageBox.Show("Duplicate File Copied to New Folder");
        }
        else
        {
          FileName = f.FileName;
          string PasteTo = b1.SelectedPath + "//" + Path.GetFileName(FileName);
          File.Copy(CopyTo, PasteTo);
          MessageBox.Show("File Copied to New Folder");
        }
      }
    }
  }
}

private void Form1_Load(object sender, EventArgs e)
{
    InitializeOpenFileDialog();
}
private void InitializeOpenFileDialog()
{
    // Set the file dialog to filter for graphics files.
    this.openFileDialog1.Filter =
        "Images (*.BMP;*.JPG;*.GIF)|*.BMP;*.JPG;*.GIF|" +
        "All files (*.*)|*.*";
    // Allow the user to select multiple images.
    this.openFileDialog1.Multiselect = true;
    this.openFileDialog1.Title = "My Image Browser";
}
private void selectFilesButton_Click(object sender, EventArgs e)
{
    DialogResult dr = this.openFileDialog1.ShowDialog();
    if (dr == System.Windows.Forms.DialogResult.OK)
    {
        // Read the files
        foreach (String file in openFileDialog1.FileNames) 
        {
            // Create a PictureBox.
            try
            {
                PictureBox pb = new PictureBox();
                Image loadedImage = Image.FromFile(file);
                pb.Height = loadedImage.Height;
                pb.Width = loadedImage.Width;
                pb.Image = loadedImage;
                flowLayoutPanel1.Controls.Add(pb);
            }
            catch (SecurityException ex)
            {
                // The user lacks appropriate permissions to read files, discover paths, etc.
                MessageBox.Show("Security error. Please contact your administrator for details.\n\n" +
                    "Error message: " + ex.Message + "\n\n" +
                    "Details (send to Support):\n\n" + ex.StackTrace
                );
            }
            catch (Exception ex)
            {
                // Could not load the image - probably related to Windows file system permissions.
                MessageBox.Show("Cannot display the image: " + file.Substring(file.LastIndexOf('\\'))
                    + ". You may not have permission to read the file, or " +
                    "it may be corrupt.\n\nReported error: " + ex.Message);
            }
        }
    }
http://msdn.microsoft.com/en-us/library/system.windows.forms.openfiledialog.multiselect.aspx