异常详细信息: System.NullReferenceException: 未将对象引用设置到对象的实例。请问我哪里弄错啦为什么一点击登录就出错

2015-10-13 05:23:04 215 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

【自动驾驶学习笔记——Prescan和Simulink 学习笔记和问题记录（1）】主要记录一些Prescan/Simulink 联合仿真出现的问题。阅读详情

web.config代码
<?xml version="1.0"?>
<configuration>
<system.web>
<compilation debug="true" targetFramework="4.0" />
</system.web>
<appSettings>
<add key="SqlConnStrName" value="server=.;database=tradeDVDDB;Integrated Security=SSPI"/>
</appSettings>
</configuration>

PublicClass代码
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;

public class PublicClass
{
public static bool ExecuteSQL(string SQLState)
{

string sqlConnStr = ConfigurationManager.ConnectionStrings["SqlConnStrName"].ConnectionString;
SqlConnection sqlConn = new SqlConnection();
sqlConn.ConnectionString = sqlConnStr;
sqlConn.Open();
SqlCommand sqlCmd = new SqlCommand();
sqlCmd.Connection = sqlConn;
sqlCmd.CommandType = CommandType.Text;
sqlCmd.CommandText = SQLState;
try
{
sqlCmd.ExecuteNonQuery();
return true;
}
catch (Exception e)
{
return false;
}
finally
{
sqlConn.Close();
}
}
public static DataSet returnDS(string SQLState)
{
string sqlConnStr = ConfigurationManager.ConnectionStrings["SqlConnStrName"].ConnectionString;//这里是出现问题的地方说没有实例哪里错啦该怎么改啊
SqlConnection sqlConn = new SqlConnection();
sqlConn.ConnectionString = sqlConnStr;
sqlConn.Open();
SqlCommand sqlCmd = new SqlCommand();
sqlCmd.Connection = sqlConn;
sqlCmd.CommandType = CommandType.Text;
sqlCmd.CommandText = SQLState;
SqlDataAdapter sqlDA = new SqlDataAdapter();
sqlDA.SelectCommand = sqlCmd;
DataSet sqlDS = new DataSet();
sqlDA.Fill(sqlDS);
return sqlDS;
}
}

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