Limiting textBox Input in C#

Code:

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;

namespace Project
{
    public class NumberBox : TextBox
    {
        public NumberBox()
        {
            this.KeyPress += new KeyPressEventHandler(NumberBox_KeyPress);
        }
        private void NumberBox_KeyPress(object sender, KeyPressEventArgs kpe)
        {
            int KeyCode = (int)kpe.KeyChar;
            if (!IsNumberInRange(KeyCode, 48, 57) && KeyCode != 8)
            {
                kpe.Handled = true;
            }
        }
        private bool IsNumberInRange(int Val, int Min, int Max)
        {
            return (Val >= Min && Val <= Max);
        }
    }
}

This is a special textbox class that only allows numerical input. It uses the KeyPress event and compares the keycode to valid inputs; it therefore allows the use of backspace and all numerics, but I do not believe it allows for decimals. I believe you can simply find what keycode the period is on and set that to allow, and have another check somewhere to disable the use of more than one decimal for this.

Not trying to be picky or anything, but what if you paste an input containing characters in there? when creating a software you must completely protect yourself from every possible way a user can make the program crash. This is a number-only implementation of TextBox coded by Koolk, mostly using a PreProcessMessage override:

Code:

using System;
    using System.Windows.Forms;

    public class KoolkTextBox : TextBox
    {
        private int Field_00 = 0x100;
        private int Field_01 = 770;

        protected override void WndProc(ref Message A_0)
        {
            if (A_0.Msg == this.Field_01)
            {
                string data = (string) Clipboard.GetDataObject().GetData(typeof(string));
                string str2 = data;
                int num = 0;
                do
                {
                    char c = str2[num];
                    if (!char.IsDigit(c))
                    {
                        A_0.Result = IntPtr.Zero;
                        return;
                    }
                    num++;
                }
                while (num < str2.Length);
            }
            base.WndProc(ref A_0);
        }

        public override bool PreProcessMessage(ref Message msg)
        {
            bool flag = true, flag2 = true, flag3 = true, flag4 = true, flag5 = true, flag6 = true;
            if (msg.Msg != this.Field_00)
            {
                return base.PreProcessMessage(ref msg);
            }
            Keys keys = (Keys) msg.WParam.ToInt32();
            if (((keys < Keys.D0) || (keys > Keys.D9)) && ((keys < Keys.NumPad0) || (keys > Keys.NumPad9)))
            {
                flag = false;
            }
            flag2 = keys == Keys.Control;
            if (keys != Keys.Z)
            {
                flag3 = false;
            }
            if (keys != Keys.X)
            {
                flag4 = false;
            }
            if (keys != Keys.C)
            {
                flag5 = false;
            }
            if (keys != Keys.V)
            {
                flag6 = false;
            }
            bool flag7 = keys == Keys.Delete;
            bool flag8 = keys == Keys.Back;
            bool flag9 = (((keys == Keys.Up) | (keys == Keys.Down)) | (keys == Keys.Left)) | (keys == Keys.Right);
            if (!(((((((flag | flag2) | flag7) | flag8) | flag9) | flag5) | flag4) | flag3))
            {
                if (!flag6)
                {
                    return true;
                }
                string data = (string) Clipboard.GetDataObject().GetData(typeof(string));
                string str2 = data;
                int num = 0;
                do
                {
                    char c = str2[num];
                    if (!char.IsDigit(c))
                    {
                        return true;
                    }
                    num++;
                }
                while (num < str2.Length);
            }
            return false;
        }
    }