using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Text;
using System.Windows.Forms;

namespace ClipboardTextBoxExample
{
    public partial class ClipboardTextBox : TextBox
    {
        private const int WM_PASTE = 0x0302;

        public delegate void ClipboardEventHandler(object sender, ClipboardEventArgs e);

        [Category("Clipboard")]
        public event ClipboardEventHandler PastedText;

        public ClipboardTextBox()
        {
            InitializeComponent();
        }

        protected override void WndProc(ref Message m)
        {
            
             if (m.Msg == WM_PASTE)
            {
                ClipboardEventArgs e = new ClipboardEventArgs(Clipboard.GetText());

                if (PastedText != null)
                {
                    string strippedText = "";
                    for (int i = 0; i < Clipboard.GetText().Length; i++)
                    {
                        if ((char.IsDigit(Clipboard.GetText()[i])) && ((Clipboard.GetText()[i]== '0') || (Clipboard.GetText()[i]=='1')))
                            strippedText += Clipboard.GetText()[i].ToString();
                    }

                    if (strippedText != Clipboard.GetText())
                    { e.Supress = true; }
                    //There were non-numbers in the pasted text
                    else
                    {
                        e.Supress = false;
                    }
                    PastedText(this, e);
                }

                if (!e.Supress)
                    base.WndProc(ref m); //only pass message along if not suppressing
            }
            else
                base.WndProc(ref m);
        }
    }

    public class ClipboardEventArgs : EventArgs
    {
        public string ClipboardText
        {
            get;
            set;
        }

        public bool Supress
        {
            get;
            set;
        }

        public ClipboardEventArgs(string clipboardText)
        {
            this.ClipboardText = clipboardText;
        }
    }
}