登陆按钮后台代码为：[size=16px][/size]
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Configuration;
public partial class Default2 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void btn_login_Click(object sender, EventArgs e)
{
SqlConnection conn = new
SqlConnection(ConfigurationManager.ConnectionStrings["connection"].ConnectionString);
SqlCommand cmd = new SqlCommand("select * from UserInfo where userID="+ txt_usetname.Text +"", conn);
try
{
conn.Open();
SqlDataReader sdr = cmd.ExecuteReader();
//如果用户名输入正确
if (sdr.Read())
{
if (sdr["userPwd"].ToString() == txt_userpwd.Text) //如果用户密码正确
{
conn.Close();//关闭数据可连接
Session["userID"] = txt_usetname.Text.Trim();//将用户id放在session中
Response.Redirect("Default.aspx");//进入 主界面
}
else
{
Response.Write("lbl_tishi.Text='密码错误'");
}
}
else//否则
{
Response.Write("lbl_tishi.Text='用户名错误'");
}
}
catch (System.Exception ee)
{
Response.Write("<script language=javascript>alert('" + ee.Message.ToString() + "')</script>");
}
finally
{
conn.Close();//关闭数据库
}
}
}
运行后错误为：[size=16px][/size]
未将对象引用设置到对象的实例。
说明: 执行当前 Web 请求期间，出现未经处理的异常。请检查堆栈跟踪信息，以了解有关该错误以及代码中导致错误的出处的详细信息。
异常详细信息: System.NullReferenceException: 未将对象引用设置到对象的实例。
源错误:
行 17: protected void btn_login_Click(object sender, EventArgs e)
行 18: {
行 19: SqlConnection conn = new
行 20: SqlConnection(ConfigurationManager.ConnectionStrings["connection"].ConnectionString);
行 21: SqlCommand cmd = new SqlCommand("select * from UserInfo where userID="+ txt_usetname.Text +"", conn);
源文件: e:\StuManage\UserLogin.aspx.cs 行: 19
堆栈跟踪:
[NullReferenceException: 未将对象引用设置到对象的实例。]
Default2.btn_login_Click(Object sender, EventArgs e) in e:\StuManage\UserLogin.aspx.cs:19
System.Web.UI.WebControls.Button.OnClick(EventArgs e) +118
System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +112
System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5563
------解决方案--------------------------------------------------------
看下数据库连接字符串获取到了吗
------解决方案--------------------------------------------------------
ConfigurationManager.ConnectionStrings["connection"]这个不会为NULL了吧，断点看看