Change the value in app.config file dynamically

Question

I want to modify a value in appSetting section in app.config. So i wrote,

Console.WriteLine(ConfigurationManager.AppSettings[\"name\"]);
Console.Read();
Conf         


        

Answer 1

 XmlReaderSettings _configsettings = new XmlReaderSettings();
 _configsettings.IgnoreComments = true;

 XmlReader _configreader = XmlReader.Create(ConfigFilePath, _configsettings);
 XmlDocument doc_config = new XmlDocument();
 doc_config.Load(_configreader);
 _configreader.Close();

 foreach (XmlNode RootName in doc_config.DocumentElement.ChildNodes)
 {
     if (RootName.LocalName == "appSettings")
     {
         if (RootName.HasChildNodes)
         {
             foreach (XmlNode _child in RootName.ChildNodes)
             {
                 if (_child.Attributes["key"].Value == "HostName")
                 {
                     if (_child.Attributes["value"].Value == "false")
                         _child.Attributes["value"].Value = "true";
                 }
             }
         }
     }
 }
 doc_config.Save(ConfigFilePath);

Answer 2

Expanding on Adis H's example to include the null case (got bit on this one)

 Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            if (config.AppSettings.Settings["HostName"] != null)
                config.AppSettings.Settings["HostName"].Value = hostName;
            else                
                config.AppSettings.Settings.Add("HostName", hostName);                
            config.Save(ConfigurationSaveMode.Modified);
            ConfigurationManager.RefreshSection("appSettings");

Answer 3

Try:

Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
config.AppSettings.Settings.Remove("configFilePath");
config.AppSettings.Settings.Add("configFilePath", configFilePath);
config.Save(ConfigurationSaveMode.Modified,true);
config.SaveAs(@"C:\Users\USERNAME\Documents\Visual Studio 2010\Projects\ADI2v1.4\ADI2CE2\App.config",ConfigurationSaveMode.Modified, true); 

Answer 4

It works, just look at the bin/Debug folder, you are probably looking at app.config file inside project.

Answer 5

You have to update your app.config file manually

// Load the app.config file
XmlDocument xml = new XmlDocument();
xml.Load(AppDomain.CurrentDomain.SetupInformation.ConfigurationFile);

// Do whatever you need, like modifying the appSettings section

// Save the new setting
xml.Save(AppDomain.CurrentDomain.SetupInformation.ConfigurationFile);

And then tell your application to reload any section you modified

ConfigurationManager.RefreshSection("appSettings");

Answer 6

This code works for me:

    Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None); 
    config.AppSettings.Settings["test"].Value = "blah";       
    config.Save(ConfigurationSaveMode.Modified);
    ConfigurationManager.RefreshSection("appSettings");

Note: it doesn't update the solution item 'app.config', but the '.exe.config' one in the bin/ folder if you run it with F5.