C#机房重构之常用限定条件汇总

限制只能输入数字

        //限制只能输入数字------------------------------------------------------
        private void txtUserID_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar != '\b' && !Char.IsDigit(e.KeyChar))
            {
                e.Handled = true;
                MessageBox.Show("请输入数字，并确保在11位以内！");
            }
        }

 

 

限制只能输入字母和数字

        //限制密码只能输入字母或者数字
        private void txtPassword_KeyPress(object sender, KeyPressEventArgs e)
        {
            if ((e.KeyChar >= 'a' && e.KeyChar <= 'z') || (e.KeyChar >= 'A' && e.KeyChar <= 'Z')
    || (e.KeyChar >= '0' && e.KeyChar <= '9') || (e.KeyChar == 8))
            {
                e.Handled = false;

            }
            else
            {
                e.Handled = true;
                MessageBox.Show("密码只能是字母或者数字");
            }
        }

 

 

限制只能输入汉字

        //添加命名空间
        using System.Text.RegularExpressions;        


        //限制只能输入汉字
        private void txtSName_KeyPress(object sender, KeyPressEventArgs e)
        {
            Regex rg = new Regex("^[\u4e00-\u9fa5\b]$"); //\b是退格键
            if (!rg.IsMatch(e.KeyChar.ToString()))
            {
                e.Handled = true;
                MessageBox.Show("您只能输入汉字！");
            }
        }