A function to modify the appsettings configuration section in Web.config

web| function This function mainly uses XmlDocument to parse web.config. Use the selectSingleNode () method to locate the configuration section that you want to modify. Note that the final program is save (), so your apsnet account must have write access to the web.config.
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<summary>
Modify the Value property in Add in the Web.config file appsettings configuration section
</summary>
<remarks>
Note that calling this function causes the entire Web application to be restarted, causing all current sessions to be lost
</remarks>
<param name= "key" > key to be modified key</param>
<param name= "strvalue" > Modified value</param>
<exception cref= "" > Cannot find related keys </exception>
<exception cref= "" > Insufficient permissions to save to Web.config file </exception>
public void Modify (String key,string strvalue)
{
String Xpath= "/configuration/appsettings/add[@key = '? ']";
XmlDocument domwebconfig=new XmlDocument ();

Domwebconfig.load ((HttpContext.Current.Server.MapPath ("Web.config"));
XmlNode Addkey=domwebconfig.selectsinglenode (Xpath.replace ("?", key));
if (Addkey = null)
{
throw new ArgumentException ("did not find <add key= '" +key+ "' value=.../> configuration section");
}
addkey.attributes["Value"]. Innertext=strvalue;
Domwebconfig.save ((HttpContext.Current.Server.MapPath ("Web.config"));

}