Wednesday, February 4, 2009

Readonly Listbox

Use the following snippet to extend the C# listBox to a readOnly List box.

using System.Windows.Forms;
namespace ReadOnlyListBox
{
public class ReadOnlyListBox : ListBox
{
private bool _readOnly = false;
public bool ReadOnly
{
get { return _readOnly; }
set { _readOnly = value; }
}

protected override void DefWndProc(ref Message m)
{
// If ReadOnly is set to true, then block any messages
// to the selection area from the mouse or keyboard.
// Let all other messages pass through to the
// Windows default implementation of DefWndProc.
if (!_readOnly || ((m.Msg <= 0x0200 || m.Msg >= 0x020E)
&& (m.Msg <= 0x0100 || m.Msg >= 0x0109)
&& m.Msg != 0x2111
&& m.Msg != 0x87))
{
base.DefWndProc(ref m);
}
}
}
}

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