如何在web.config文件中编写连接字符串并从中读取 [英] how to write connection string in web.config file and read from it

问题描述

我正在尝试将Connectionstring写入Web.config，如下所示：

i'm trying to write Connectionstring to Web.config like this:

<connectionStrings>
    <add name="Dbconnection" connectionString="Server=localhost; Database=OnlineShopping ; Integrated Security=True"/>
  </connectionStrings >

并阅读就像这样：

and read from it like this:

string strcon = ConfigurationManager.ConnectionStrings["Dbconnection"].ConnectionString;
SqlConnection DbConnection = new SqlConnection(strcon);

运行progrom时
我收到错误因为空引用。

但是当我使用这段代码时：

when run the progrom I get an error because of the null reference.
but when I use this code:

SqlConnection DbConnection = new SqlConnection();
DbConnection.ConnectionString = "Server=localhost; Database=OnlineShopping ; Integrated Security=True";

我没有收到任何错误，程序工作正常！

有什么问题？

Tanx！

I don't get any error and the program work correctly!
What is the problem?
Tanx!

推荐答案

<connectionstrings>
		<add name="Your Connection string name" connectionstring="data source=server name;Database=database name;uid=Database Username;pwd=password;multipleactiveresultsets=true;" providername="System.Data.SqlClient" />
	</connectionstrings>

For Call Connection string write the below code

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["Connection string name"].ConnectionString.ToString());

Connection string name means "Your Connection string name"

检查您的Web.config连接字符串。

Check your Web.config Connection string.

<connectionStrings>
    <add name="Dbconnection" connectionString="Data Source=localhost;Initial Catalog=OnlineShopping;Integrated Security=true" providerName="System.Data.SqlClient" />

没有'除了缺少初始目录之外，您的连接字符串似乎有任何问题。您已将其指定为数据库，但在连接字符串中，我们将其指定为初始目录。所以，重新编写你的连接字符串，然后再试一次：

There doesn't seem anything wrong with your connection string other than the 'Initial Catalog' missing from it. You have specified it as Database, but in a connection string, we specify it as Initial Catalog. So, re-write your connection string as below and try again:

<connectionStrings>
    <add name="Dbconnection" connectionString="Server=localhost;Initial Catalog=OnlineShopping;Integrated Security=True"/>
  </connectionStrings >

佛详细信息，您可以访问 http://msdn.microsoft.com/en-us/library/ms178411 .aspx [ ^ ]同样。

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