未将对象引用设置到对象的实例。

Question

protected void login_Click(object sender, EventArgs e)
    {        string strConn = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        SqlConnection conn = new SqlConnection(strConn);
        string sql = "select * from [user] where user_id='" + txtName.Text + "'";
        SqlCommand Comm = new SqlCommand(sql, conn);
        conn.Open();
        SqlDataReader reader = Comm.ExecuteReader();
        if(reader.HasRows)
        {
            reader.Read();
            if (reader["password"].ToString() == password.Text)
            {
                Session["user_id"] = txtName.Text;
                Response.Redirect("admin_index.html");
             }
             else
             {
                 message.Text = "密码不正确！";
              }
          }
          else
          {
                 message.Text = "对不起，用户名不存在！";
           }
    }
主要是这句话 string strConn = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
说我没有引用，我应该怎么改呢？

Answer 1

string strConn = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;你的配置文件有连接字符串的配置吗，配置文件内容贴出来。

Answer 2

你的连接字符串呢
["ConnectionString"]应该有个初始值吧

Answer 3

using System;
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 System.Data.SqlClient;public partial class Default2 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {    }
    protected void login_Click(object sender, EventArgs e)
    {        string strConn = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        SqlConnection conn = new SqlConnection(strConn);
        string sql = "select * from [user] where user_id='" + txtName.Text + "'";
        SqlCommand Comm = new SqlCommand(sql, conn);
        conn.Open();
        SqlDataReader reader = Comm.ExecuteReader();
        if(reader.HasRows)
        {
            reader.Read();
            if (reader["password"].ToString() == password.Text)
            {
                Session["user_id"] = txtName.Text;
                Response.Redirect("admin_index.html");
             }
             else
             {
                 message.Text = "密码不正确！";
              }
          }
          else
          {
                 message.Text = "对不起，用户名不存在！";
           }
    }
}

Answer 4

我没有配置webconfig
这个要怎么配置啊

Answer 5

晕倒，没有配置文件，你这个不报错，才不正常！
tring strConn = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;添加新项，选择配置文件。

Answer 6

我是指在webconfig里面要怎么写代码呢

Answer 7

<configuration>
<configSections>
<sectionGroup name="system.web.extensions" type="System.Web.Configuration.SystemWebExtensionsSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
<sectionGroup name="scripting" type="System.Web.Configuration.ScriptingSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
<section name="scriptResourceHandler" type="System.Web.Configuration.ScriptingScriptResourceHandlerSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
<sectionGroup name="webServices" type="System.Web.Configuration.ScriptingWebServicesSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
<section name="jsonSerialization" type="System.Web.Configuration.ScriptingJsonSerializationSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="Everywhere"/>
<section name="profileService" type="System.Web.Configuration.ScriptingProfileServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
<section name="authenticationService" type="System.Web.Configuration.ScriptingAuthenticationServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
<section name="roleService" type="System.Web.Configuration.ScriptingRoleServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
</sectionGroup>
</sectionGroup>
</sectionGroup>
</configSections>
<connectionStrings>
    <add name="spectempConnectionString" connectionString="Data Source=Sstr;Initial Catalog=Sstrdb;Integrated Security=True" providerName="System.Data.SqlClient"/>
</connectionStrings>
<appSettings>需要添加
<connectionStrings>
    <add name="ConnectionString" connectionString="Data Source=Sstr;Initial Catalog=Sstrdb;Integrated Security=True" providerName="System.Data.SqlClient"/>
</connectionStrings>配置

Answer 8

ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
没具体东西啊

Answer 9

ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
就是上面语句取到得东西为空，这个值从哪来的

Answer 10

LZ在Web.config配制文件里
改下这个就可以了
<connectionStrings>
  <add name="ConnectionString" connectionString="Data Source=Sstr;Initial Catalog=Sstrdb;Integrated Security=True" providerName="System.Data.SqlClient"/>
</connectionStrings>

Answer 11

还是会出现一样的错误。未将对象引用设置到对象的实例。排错提示是说：使用NEW关键字创建对象实例。在调用方法前通过检查确定对象是否为NULL。哪位好心人能加我QQ，方便交流啊！181202936