未将对象引用设置到对象的实例。 - C# 论坛

问题点数：0 回复次数：8

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:

执行当前 Web 请求期间生成了未处理的异常。可以使用下面的异常堆栈跟踪信息确定有关异常原因和发生位置的信息。

堆栈跟踪:

[NullReferenceException: 未将对象引用设置到对象的实例。]
   MasterPage.Page_Load(Object sender, EventArgs e) in D:\桌面\SupermarkeMembertSys\SupermarkeMembertSys\MasterPage.master.cs:13
   System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14
   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35
   System.Web.UI.Control.OnLoad(EventArgs e) +99
   System.Web.UI.Control.LoadRecursive() +50
   System.Web.UI.Control.LoadRecursive() +141
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627

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第 2 楼

得分:0

请求各位大大帮忙啊本人小白不会调试啊

第 3 楼

得分:0

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="login.aspx.cs" Inherits="SupermarkeMembertSys.login" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.

<html xmlns="http://www. >
<head runat="server">
    <title></title>
</head>
<body bottommargin="0" topmargin="0" bgcolor="#14315f">
    <form id="form1" runat="server">
<div align="center">
<table id="Table1" width="1003" height="613" border="0" cellpadding="0" cellspacing="0">
    <tr>
        <td colspan="8">
            <img src="images/login_01.gif" width="1003" height="2" alt=""></td>
    </tr>
    <tr>
        <td rowspan="5">
            <img src="images/login_02.gif" width="68" height="611" alt=""></td>
        <td rowspan="4">
            <img src="images/login_03.gif" width="23" height="608" alt=""></td>
        <td colspan="5">
            <img src="images/login_04.gif" width="847" height="318" alt=""></td>
        <td rowspan="5">
            <img src="images/login_05.gif" width="65" height="611" alt=""></td>
    </tr>
    <tr>
        <td rowspan="2">
            <img src="images/login_06.gif" width="381" height="84" alt=""></td>
        <td width="162" height="83" rowspan="2" background="images/login_07.gif" class="newStyle1">用户名：<asp:TextBox
                ID="TextBox1" runat="server" Width="101px"></asp:TextBox>
            <br />
            <br />
            密  码：<asp:TextBox ID="TextBox2" runat="server" Width="101px"
                TextMode="Password" BorderStyle="None"></asp:TextBox>
            <br />
        </td>
        <td rowspan="2">
            <img src="images/login_08.gif" width="26" height="84" alt=""></td>
        <td width="67" height="39" background="images/login_09.gif">
            <asp:ImageButton ID="ImageButton1" runat="server"
                ImageUrl="~/images/botton1.gif" Height="20px"
                onclick="ImageButton1_Click" />
        </td>
        <td rowspan="2">
            <img src="images/login_10.gif" width="211" height="84" alt=""></td>
    </tr>
    <tr>
        <td width="67" height="45" background="images/login_11.gif">
            <asp:ImageButton ID="ImageButton2" runat="server"
                ImageUrl="~/images/botton2.gif" Height="20px"
                onclick="ImageButton2_Click" />
        </td>
    </tr>
    <tr>
    <td height="206" colspan="5" align="center" valign="top" background="images/login_12.gif" class="newStyle1"> <br />
             
        验证码： <asp:TextBox ID="TextBox3" runat="server"
            Width="98px"></asp:TextBox>
        <asp:Image ID="Image1" runat="server" ImageUrl="~/AppCode/GetImageCode.aspx" />
                    <br />
        <asp:SqlDataSource ID="SqlDataSource1" runat="server"
            ConnectionString="<%$ ConnectionStrings:ConnectionString %>"

            SelectCommand="SELECT [UserID], [UserPassword], [UserType], [UserName] FROM [User] WHERE (([UserName] = @UserName) AND ([UserPassword] = @UserPassword))"
            DataSourceMode="DataReader">
            <SelectParameters>
                <asp:ControlParameter ControlID="TextBox1" Name="UserName"
                    PropertyName="Text" />
                <asp:Parameter Name="UserPassword" Type="String" />
            </SelectParameters>
        </asp:SqlDataSource>
                    <br />
        <asp:Label ID="Label1" runat="server"></asp:Label>
                    <asp:Label ID="Label2" runat="server"></asp:Label>
                    </td>
    </tr>
    <tr>
        <td colspan="6">
            <img src="images/login_13.gif" width="870" height="3" alt=""></td>
    </tr>
</table>
    </div>
    </form>
</body>
</html>

第 4 楼

得分:0

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;

namespace SupermarkeMembertSys
{
    public partial class login : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                //Session["CheckCode"] = "";
                Response.Cookies.Add(new HttpCookie("CheckCode", ""));
            }

        }

        protected void ImageButton1_Click(object sender, ImageClickEventArgs e)
        {
            //先进行验证码的比较操作
            if ((Request.Cookies["CheckCode"].Value, TextBox3.Text.ToString().Trim(), true) != 0)
            {
                Label2.Text = "验证码错误，请输入正确的验证码。";
                Label2.Visible = true;
                return;
            }
            else
            {
                Label2.Text = "验证码OK。";
                Label2.Visible = true;
                //跟数据库比较用户名密码是否一样
                HttpCookie mycookie;
                string pwd = TextBox2.Text.Trim();
                pwd = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(pwd, "MD5");
                SqlDataSource1.SelectParameters["UserPassword"].DefaultValue = pwd;
                using (IDataReader mdr = (IDataReader)SqlDataSource1.Select(DataSourceSelectArguments.Empty))
                {
                    if (mdr.Read())
                    {
                        string UserID = mdr[0].ToString();
                        string UserType = mdr[2].ToString();
                        string UserName = mdr[3].ToString();
                        mycookie = new HttpCookie("UserID", UserID);
                        Response.AppendCookie(mycookie);
                        mycookie = new HttpCookie("UserType", UserType);
                        Response.AppendCookie(mycookie);
                        mycookie = new HttpCookie("UserName", UserName);
                        Response.AppendCookie(mycookie);
                        Response.Redirect("Default.aspx");
                    }
                    else
                        Label1.Text = "您输入的密码与用户名不匹配,请重输!";
                }

            }

        }

        protected void ImageButton2_Click(object sender, ImageClickEventArgs e)
        {
            TextBox1.Text = "";
            TextBox2.Text = "";
        }
    }
}