如何设定控件的输入内容限制？

Question

如果是DevExpress的控件有个Mark属性可以输入正则表达式来限定输入格式的。很好用

Answer 1

先感谢1楼老兄，正则表达式~
我是用VS2005 C#写WinForm
        private void txtUserID_TextChanged(object sender, EventArgs e)
        {
            if (txtUserID.Text.Length > 0)
            {
                if (Encoding.Default.GetByteCount (txtUserID.Text) > 20)
                {
                    int selIndex = txtUserID.SelectionStart;
                    int selLength = txtUserID.SelectionLength;
                    txtUserID.Text = txtUserID.Text.Substring(0, txtUserID.Text.Length - 1);
                    if (selIndex > txtUserID.Text.Length)
                    {
                        selIndex = txtUserID.Text.Length + 1;
                        selLength = 0;
                    }
                    else
                    {
                        if (selLength > txtUserID.Text.Length - selIndex)
                        {
                            selLength = txtUserID.Text.Length - selIndex;
                        }
                    }
                    txtUserID.SelectionStart = selIndex;
                    txtUserID.SelectionLength = selLength;
                }
            }
        }
只能想到这样，再具体、苛刻点怎么加工呢？

Answer 2

查了下，确实没用过，介绍也挺简单人性化的，但是Using跟引用是啥没有找到，照搬原样肯定报错。“网上能轻松查到”我也不必跟这里了是吧