C#键位定制：设置一个文本框只能输入数字键

 /// <summary>
        /// 键盘事件：设置文本框能输入数字键与'.'
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void txtTest_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar != 8 && !Char.IsDigit(e.KeyChar))   //可以是数字键与Backspace
            {
                e.Handled = true;
                if (e.KeyChar == '.')   //可以输入‘.’
                {
                    e.Handled = txtTest.Text.IndexOf('.') >= 0;
                }
            }
        }