C#怎么对页面文本框输入的字符串进行验证?
using System;using System.Collections;using System.Configuration;using System.Data;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.HtmlControls;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using WF_BLL;using WF_Model;using System.Text.RegularExpressions;public partial class Login : System.Web.UI.Page{ protected void Page_Load(object sender, EventArgs e) { }protected void btn_Login_Click(object sender, EventArgs e) { if (!(checking(this.txt_Username.Text.Trim()) || checkings(this.txt_Username.Text.Trim()))) { Response.Write("<script> alert('只能是数字、字母、下划线、汉字!')</script>"); } else { UserInfo info = new UserInfo(); info.UserName = this.txt_Username.Text.Trim(); info.PassWord = this.txt_Password.Text.Trim(); Login_BLL login = new Login_BLL(); bool value = login.Login(info); if (!value) { Response.Write("<script> alert('注册成功!')</script>"); } else { Response.Write("<script> alert('注册失败!')</script>"); } } } public static bool checking(string strings) { return Regex.IsMatch(strings, @"^[0-9a-zA-Z_]+$"); } public static bool checkings(string strings) { return Regex.IsMatch(strings, @"^[\u4e00-\u9fa5],{0,}$"); }}