throw new Exception("登录失败");用户代码未处理Exception 怎么修改

Question

Default.aspx.cs：

namespace LoginUI
{
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

    }

    protected void btnLogin_Click(object sender, EventArgs e)
    {
        ///通常,直接使用DAO呼叫数据库。
        //IDbConnection conn = new SqlConnection("C....");
        //IDbCommand cmd=conn.CreateCommand();
        //cmd.CommandText ="Select UserName From USERS WHERE .....";
        //cmd.ExecuteReader();

        //利用三层架构,需要引用下一层的
        string userName = txtUserName.Text.Trim();
        string password = txtPwd.Text;
        LoginBLL.LoginManager mgr = new LoginBLL.LoginManager();
        LoginModel.UserInfo user = mgr.UserLogin(userName, password);

        MessageBox.Show("登录用户：" + user.UserName);
    }
}

}

LoginManager.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace LoginBLL
{
public class LoginManager
{
public LoginModel.UserInfo UserLogin(string userName,string password)
{
//throw new NotImplementedException();
//呼叫数据源，获取相应数据
LoginDAL.UserDAO uDao = new LoginDAL.UserDAO();
LoginModel.UserInfo user = uDao.SelectUser(userName, password);
if(user !=null)//login successful
{
//如果登陆成功，则增加10点积分。
LoginDAL.ScoreDAO sDao = new LoginDAL.ScoreDAO();
sDao.UpdateScore(userName, 10);
return user;
}
else
{
throw new Exception("登录失败");
}
}
}
}

Answer 1

 LoginModel.UserInfo user = mgr.UserLogin(userName, password);

->
try
{
LoginModel.UserInfo user = mgr.UserLogin(userName, password);
}
catch
{
MessageBox.Show("登录失败");
}