C#

class AboutForm : Form
{
  Timer timer = new Timer();
  double STEP = 8 / 256.0;
  public AboutForm()
  {
    Opacity = 0;
    timer.Interval = (int)(1000 * STEP);
    timer.Tick += new EventHandler(timer_Tick);

    BackColor = Color.White;
    Size = new Size(512, 420);
    ShowInTaskbar = false;
    FormBorderStyle = FormBorderStyle.None;
    StartPosition = FormStartPosition.CenterParent;
    TransparencyKey = Color.Black;
    Image i = Image.FromStream(Assembly.GetExecutingAssembly().GetManifestResourceStream("splash.png"));

    Bitmap b = new Bitmap(i);
    b.MakeTransparent(Color.White);

    BackgroundImage = b;

    SetStyle(ControlStyles.DoubleBuffer | ControlStyles.AllPaintingInWmPaint, true);
    UpdateStyles();
  }

  protected override void OnHandleCreated(EventArgs e)
  {
    base.OnHandleCreated(e);
    timer.Start();
  }

  private void timer_Tick(object sender, EventArgs e)
  {
    if (Opacity >= 1.0)
    {
      timer.Stop();
      return;
    }

    Opacity += STEP;
    STEP *= 1 / 1.01;
  }
}

long FileSize = new FileInfo("C:\\boot.ini").Length;

Form2 f2 = new Form2();
			
f2.Show();

//shift the focus to the main form
this.Focus();

IDataObject oldData = Clipboard.GetDataObject();
// Construct your new DataObject and set it, then later...
Clipboard.SetDataObject();

IDataObject oldData = Clipboard.GetDataObject();
System.Windows.Forms.DataObject prevDat = new DataObject();

prevDat.SetData(oldData);

//
//.....
//...code for pasting operation here
//.........
//

 Clipboard.SetDataObject(prevDat,true);

IDataObject oldData = Clipboard.GetDataObject();
// Make your own DataObject. DO NOT TOUCH oldData
Clipboard.SetDataObject(oldData);

private void PasteImg(RichTextBox richTextBox1, string imageFileName)
{
	//Copy the previous clipped data
	IDataObject oldData = Clipboard.GetDataObject();



	#region Pasting the image
	if("" == imageFileName) imageFileName = @"c:\JayShared\music.bmp";


	Bitmap myBitmap = new Bitmap(imageFileName);

	// Copy the bitmap to the clipboard.
	Clipboard.SetDataObject(myBitmap, false);

	// Get the format for the object type.
	DataFormats.Format myFormat = DataFormats.GetFormat (DataFormats.Bitmap);

	// After verifying that the data can be pasted, paste
	if(richTextBox1.CanPaste(myFormat)) 
	{
		richTextBox1.Paste();
	}


	#endregion Pasting the image

	//
	//paste back the previous clipped data to the clipboard

	Clipboard.SetDataObject(oldData); //.......... Error occurs here.........


	//
}

IDataObject prevDat = Clipboard.GetDataObject();