numerictextbox.cs

清华大学出版社出版的 移动应用开发宝典 张大威（2008）的附书源代码

using System;
using System.Windows.Forms;


namespace Chapter15.Windows.Forms
{
    public class NumericTextBox : TextBox 
    {
        private bool blockedKey = false;

        protected override void OnKeyPress(KeyPressEventArgs e)
        {
            if (blockedKey)
            {
                e.Handled = true;
            }
        }
        protected override void OnKeyDown(KeyEventArgs e)
        {
            blockedKey = false;
            if (e.Shift == true || e.Alt == true)
            {
                blockedKey = true;
                return;
            }
            if (e.KeyCode < Keys.D0 || e.KeyCode > Keys.D9)
            {
                if (e.KeyCode < Keys.NumPad0 || e.KeyCode > Keys.NumPad9)
                {
                    if (e.KeyCode != Keys.Back)
                    {
                        blockedKey = true;
                    }
                }
            }
        }

        
    }
}