C#

private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
   for (int i =1 ;i< numericUpDown1.Value;i++) {
      e.Graphics.DrawLine(Pens.Red, 10 + i, 10, 10 + i, 10 + i);
   }
}

private void numericUpDown1_ValueChanged(object sender, System.EventArgs e)
{
    this.Invalidate();
}

CollectionBase<IDiagramEntity> copy = MyDeepCopyOfTheCollectionViaSerialization();
DataFormats.Format format =
DataFormats.GetFormat(typeof(CollectionBase<IDiagramEntity> ).FullName);
IDataObject dataObject = new DataObject();
dataObject.SetData(format.Name, false, copy);
Clipboard.SetDataObject(dataObject, false);

CollectionBase<T> newobj = null;
MemoryStream stream = new MemoryStream();
GenericFormatter<BinaryFormatter> f = new
GenericFormatter<BinaryFormatter>();
f.Serialize(stream, this);
stream.Seek(0, SeekOrigin.Begin);
newobj = f.Deserialize<CollectionBase<T>>(stream);
stream.Close();
return newobj;

IDataObject data = Clipboard.GetDataObject();
string format = typeof(CollectionBase<IDiagramEntity> ).FullName;
if (data.GetDataPresent(format))
{
 //data.GetData(format) is a MemoryStream rather than a generic collection!  X| 
}