Is it possible to disable a textbox from selecting a piece of text with a double click

It doesn't look like you can do this with standard WinForms event handlers ( DoubleClick

and MouseDoubleClick

doesn't give you the ability to suppress the default behavior), but you can do it by creating a custom one WndProc

and handling window messages yourself.

In the example below, I am overriding the default Control.WndProc

in the class PreviewTextBox

I am creating. I expose the event PreviewDoubleClick

through this class, which, if handled in client code, can be used to suppress the default double-click behavior by setting e.Handled = true;

. In this example, the event is handled in an event handler OnPreviewDoubleClick

, where you can add your own code to respond to the double click, but you want.

If you need more information on double click I believe you can get it via Message.LParam

/ Message.WParam

in WndProc

.

(the code below assumes you have the code for an already configured form)

using System;
using System.Windows.Forms;

namespace WindowsFormsApplication2
{
    class DoubleClickEventArgs : EventArgs
    {
        public bool Handled
        {
            get;
            set;
        }
    }

    class PreviewTextBox : TextBox
    {
        public event EventHandler<DoubleClickEventArgs> PreviewDoubleClick;

        protected override void WndProc(ref Message m)
        {
            if ((m.Msg == WM_DBLCLICK) || (m.Msg == WM_LBUTTONDBLCLK))
            {
                var e = new DoubleClickEventArgs();

                if (PreviewDoubleClick != null)
                    PreviewDoubleClick(this, e);

                if (e.Handled)
                    return;
            }

            base.WndProc(ref m);
        }

        const int WM_DBLCLICK = 0xA3;
        const int WM_LBUTTONDBLCLK = 0x203;
    }

    public partial class TestForm : Form
    {
        public TestForm()
        {
            InitializeComponent();

            _textBox = new PreviewTextBox();
            _textBox.Text = "Test text foo bar";
            _textBox.PreviewDoubleClick += new EventHandler<DoubleClickEventArgs>(OnPreviewDoubleClick);

            Controls.Add(_textBox);
        }

        void OnPreviewDoubleClick(object sender, DoubleClickEventArgs e)
        {
            e.Handled = true;
        }

        PreviewTextBox _textBox;
    }
}