C＃SqlCommand Connection.Open（）问题

我有一个C＃ASP.NET Web应用程序我想填充一个ASP：DropDownList与数据库表中的列。C＃SqlCommand Connection.Open（）问题

我的代码：

using System; 
using System.Collections.Generic; 
using System.Web; 
using System.Web.UI; 
using System.Web.UI.WebControls; 
using System.Data; 
using System.Data.SqlClient; 
using System.Configuration; 
using System.Web.Configuration; 

namespace CRM2Sage 
{ 
    public partial class SOPOrderEntry : System.Web.UI.Page 
    { 
     protected void Page_Load(object sender, EventArgs e) 
     { 
      Fill1(); 
     } 

     public void Fill1() 
     { 
      SqlCommand cmd = new SqlCommand("SELECT * FROM Products", new SqlConnection(WebConfigurationManager.AppSettings["CRM2Sage"])); 
      //cmd.Connection.Open(); 
      cmd.Connection.Open(); 

      SqlDataReader ddlValues; 
      ddlValues = cmd.ExecuteReader(); 

      vproduct.DataSource = ddlValues; 
      vproduct.DataValueField = "theName"; 
      vproduct.DataTextField = "theName"; 
      vproduct.DataBind(); 

      cmd.Connection.Close(); 
      cmd.Connection.Dispose(); 
     } 
    } 
}

的，当我运行页面，我得到以下错误

ConnectionString属性已尚未初始化。

指向cmd.Connection.Open();我不明白为什么，SQL连接存储在我的web.config文件中。

的web.config

<?xml version="1.0"?> 
<configuration> 

    <appSettings /> 
    <connectionStrings> 
     <add name="CRM2Sage" connectionString="Data Source=W2003CRMDEMO; Initial Catalog=CRM2Sage; User ID=newSA; Password=password;" providerName="System.Data.SqlClient" /> 
    </connectionStrings> 

    <system.web> 
     <compilation debug="true"> 

     </compilation> 
     <!-- 
      The <authentication> section enables configuration 
      of the security authentication mode used by 
      ASP.NET to identify an incoming user. 
     --> 
     <authentication mode="Windows" /> 
     <!-- 
      The <customErrors> section enables configuration 
      of what to do if/when an unhandled error occurs 
      during the execution of a request. Specifically, 
      it enables developers to configure html error pages 
      to be displayed in place of a error stack trace. 

     <customErrors mode="RemoteOnly" defaultRedirect="GenericErrorPage.htm"> 
      <error statusCode="403" redirect="NoAccess.htm" /> 
      <error statusCode="404" redirect="FileNotFound.htm" /> 
     </customErrors> 
     --> 
    </system.web> 
</configuration>

谁能帮助？

干杯

贾斯汀

来源

2011-03-28 Justin Erswell

我没有看到任何错误？ – 2011-03-28 14:45:29

您需要检索.ConnectionString属性：

string connectionString = WebConfigurationManager.ConnectionStrings["CRM2Sage"].ConnectionString; 

using(SqlConnection _con = new SqlConnection(connectionString)) 
using(SqlCommand cmd = new SqlCommand("SELECT * FROM Products", _con)) 
{ 
    // do your stuff here 
}

你是什么现在正在执行的是<connectionStrings>下的CRM2Sage这个名字。

来源

2011-03-28 14:47:01

+1添加代码示例 – IAbstract 2011-03-28 14:51:55

的问题是，你正在访问AppSettings，但你要访问的连接字符串：

new SqlConnection(WebConfigurationManager.ConnectionStrings.ConnectionStrings["CRM2Sage"].ConnectionString)

来源

2011-03-28 14:46:19

你可以在asp.net使用

System.Web.Configuration.WebConfigurationManager.ConnectionStrings["CRM2Sage"].ConnectionString; 

Or 
System.Configuration.ConfigurationManager.ConnectionStrings["CRM2Sage"].ConnectionString;

。但不是

WebConfigurationManager.AppSettings["CRM2Sage"]

来源

2011-03-28 14:55:39 AEMLoviji

C＃SqlCommand Connection.Open（）问题

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