C # ASP. NET Modify Webconfig file configuration

#regionModify config file/// <summary>  ///Modify config file (appsetting node)/// </summary>  /// <param name= "key" >Key</param>  /// <param name= "value" >the value to modify into</param>   Public Static voidUpdateappsetting (stringKeystringvalue) {XmlDocument doc=NewXmlDocument (); //get the full path of the configuration file    stringstrFileName = AppDomain.CurrentDomain.BaseDirectory.ToString () +"Web. config"; Doc.      Load (strFileName); //find all elements with the name "add"XmlNodeList nodes = doc. getElementsByTagName ("Add");  for(inti =0; I < nodes. Count; i++)      {          //gets the key property of the current elementXmlAttribute _key = nodes[i]. attributes["Key"]; //determines whether the current element is a target element based on the first attribute of the element        if(_key! =NULL)          {              if(_key. Value = =key) {                  //assign a value to the second attribute in the target element_key = Nodes[i]. attributes["value"]; _key. Value=value;  Break; }          }      }      //Save the changes aboveDoc.  Save (strFileName); }    /// <summary>  ///Modify config file (connectionstring node)/// </summary>  /// <param name= "name" >Key</param>  /// <param name= "value" >the value to modify into</param>   Public Static voidUpdateconnectionstring (stringNamestringvalue) {XmlDocument doc=NewXmlDocument (); //get the full path of the configuration file    stringstrFileName = AppDomain.CurrentDomain.BaseDirectory.ToString () +"Web. config"; Doc.      Load (strFileName); //find all elements with the name "add"XmlNodeList nodes = doc. getElementsByTagName ("Add");  for(inti =0; I < nodes. Count; i++)      {          //gets the key property of the current elementXmlAttribute _name = nodes[i]. attributes["name"]; //determines whether the current element is a target element based on the first attribute of the element        if(_name! =NULL)          {              if(_name. Value = =name) {                  //assign a value to the second attribute in the target element_name = Nodes[i]. attributes["connectionString"]; _name. Value=value;  Break; }          }      }      //Save the changes aboveDoc.  Save (strFileName); }  #endregion  

C # ASP. NET Modify Webconfig file configuration