如何动态更改为web.config中的连接字符串 [英] how to change to connection string in web.config dynamically

问题描述

我在web.config中找到了连接字符串

 < ConnectionStrings><添加name ="student" connectionString ="Server = student;最大池大小= 300;初始目录= studentDB;用户ID = student;密码= st123dent;"providerName ="System.Data.SqlClient"/></连接字符串> 

如何在C#中动态更改连接字符串

解决方案

配置是只读的，因此您不能像

这样的明显方式进行配置

  ConfigurationManager.ConnectionStrings ["student"].ConnectionString =新值"; 

这会引发 System.Configuration.ConfigurationErrorsException 异常上面写着配置是只读的".

这是一个使用反射来重置配置元素的readOnly属性的技巧.有关详细信息，请参见本文以编程方式设置connectionString属性

代码段:

  var设置= ConfigurationManager.ConnectionStrings [0];var fi = typeof(ConfigurationElement).GetField("_bReadOnly"，BindingFlags.Instance |BindingFlags.NonPublic);fi.SetValue(settings，false);settings.ConnectionString =数据源=某事"; 

顺便说一句，为什么您需要更改其配置?我感觉到您正在尝试以错误的方式解决某些问题.

I defind the connection string in web.config

     <ConnectionStrings>
 <add name="student" connectionString="Server=student;Max Pool Size=300;Initial Catalog=studentDB;User ID=student;Password=st123dent;" providerName="System.Data.SqlClient"/>
     </Connectionstrings>

how can i change the connection string dynamically in c#

解决方案

Configuration is read only so you can not do it in obvious way like

ConfigurationManager.ConnectionStrings["student"].ConnectionString = "new value";

This raises System.Configuration.ConfigurationErrorsException exception which saying that "Configuration is read only".

Here is a trick using reflection to reset readOnly attribute of configuration element. See this article for full details Programmatically setting a connectionString property

Code snippet:

var settings = ConfigurationManager.ConnectionStrings[ 0 ];
var fi = typeof(ConfigurationElement).GetField(
              "_bReadOnly", 
              BindingFlags.Instance | BindingFlags.NonPublic);
fi.SetValue(settings, false);
settings.ConnectionString = "Data Source=Something";

BTW, why you need change it the configuration? I'm feeling that you'are trying to solve some problem in wrong way.

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