TextBox限制输入字母、数字、退格键

公共方法如下：

　　　　　　/// <summary>
        /// 正则表达式验证只能输入数字或字母
        /// </summary>
        /// <param name="pendingString"></param>
        /// <returns></returns>
        public bool IsNaturalOrNumber(string str)
        {
            System.Text.RegularExpressions.Regex reg1 = new System.Text.RegularExpressions.Regex(@"^[A-Za-z0-9-]+$");
            return reg1.IsMatch(str);
        }

        /// <summary>
        /// 正则表达式验证只能输入数字
        /// </summary>
        /// <param name="pendingString"></param>
        /// <returns></returns>
        public bool IsNumber(string str)
        {
            System.Text.RegularExpressions.Regex reg1 = new System.Text.RegularExpressions.Regex(@"^[0-9-]+$");
            return reg1.IsMatch(str);
        }

        /// <summary>
        /// 正则表达式验证只能输入字母
        /// </summary>
        /// <param name="pendingString"></param>
        /// <returns></returns>
        public bool IsNatural(string str)
        {
            System.Text.RegularExpressions.Regex reg1 = new System.Text.RegularExpressions.Regex(@"^[A-Za-z-]+$");
            return reg1.IsMatch(str);
        }

应用如下：

     private void textBox1_TextChanged(object sender, EventArgs e)
        {
            if (string.IsNullOrEmpty((sender as TextBox).Text)) return;
            if (!IsNumber((sender as TextBox).Text))
            {
                this.textBox1.Text = this.textBox1.Text.Substring(0, this.textBox1.Text.Length - 1);
                this.textBox1.SelectionStart = this.textBox1.Text.Length;
                return;
            }
        }