C＃SqlCommand Connection.Open（）问题 [英] C# SqlCommand Connection.Open() issue

问题描述

我有一个C＃ASP.NET Web应用程序，我试图用数据库表中的列填充ASP：DropDownList。

I have a C# ASP.NET web application an I am trying to populate an ASP:DropDownList with a column in a database table.

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();
        }
    }
}

我在运行页面时我收到以下错误消息

An when I run the page I get the following error

ConnectionString属性的
尚未初始化。

The ConnectionString property has not been initialized.

指向 cmd.Connection.Open（）; 我不明白为什么，SQL连接存储在我的Web中。配置文件。

pointing to cmd.Connection.Open(); I can not understand why, the SQL connection is stored in my web.config file.

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>

有人可以帮忙吗？

欢呼

贾斯汀

推荐答案

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
}

您现在正在做的只是在找东西< connectionStrings> 下的整个条目，名称为 CRM2Sage 。

What you're doing right now is just retrieving the whole entry under <connectionStrings> by the name of CRM2Sage.

这篇关于C＃SqlCommand Connection.Open（）问题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！