Question

ConfigurationManager.ConnectionStrings["Connection"].ConnectionString;提示未将设置引用到对象实例

后台代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
namespace WebApplication4
{
public partial class WebForm1 : System.Web.UI.Page
{
string str = ConfigurationManager.ConnectionStrings["Connection"].ConnectionString;
protected void Page_Load(object sender, EventArgs e)
{
SqlDataAdapter mysqlada = new SqlDataAdapter("select * from Stu",str);
DataSet myset = new DataSet();
mysqlada.Fill(myset,"News");
GridView1.DataSource = myset.Tables["News"].DefaultView;
GridView1.DataBind();
}
}
}
web.config里配置代码；
<?xml version="1.0" encoding="utf-8"?>

<!-- 有关使用 web.config 转换的详细信息，请访问 http://go.microsoft.com/fwlink/?LinkId=125889 -->

<configuration xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform">
<connectionString>
<add name="Connection" connectionString="Server=.;uid=sa;pwd=123;database=Student"/>
</connectionString>
<system.web>

</system.web>
</configuration>

Answer 1

public partial class WebForm1 : System.Web.UI.Page
{

protected void Page_Load(object sender, EventArgs e)
{
string str = ConfigurationManager.ConnectionStrings["Connection"].ConnectionString; SqlDataAdapter mysqlada = new SqlDataAdapter("select * from Stu",str);
DataSet myset = new DataSet();
mysqlada.Fill(myset,"News");
GridView1.DataSource = myset.Tables["News"].DefaultView;
GridView1.DataBind();
}
}

换成这样 试试呢

追问

不行 还是同样的错误

追答

打断点调试一下 确保是否是 ConfigurationManager.ConnectionStrings["Connection"]为空
System.Configuration 该引用版本是多少啊

追问

找到原因了 是数据库无法连接

Console.Write(conn.State);
不显示open状态,这怎么回事啊，但用SqlDataSource控件绑定的话就可以

追答

你打断点看看 vs调试功能这么强大 多利用 要学会调试