How do I: Change app.config?

Question

Hello: In my project there is an item that is named 'app.config'. Is there a way I can programmatically change it?

Jaish Mathews · Answer

Hi, Windows application converts all App.Config to App.Config.exe. So you need to work with that file. Builtin finctionality available like below. I am livel using for one of my application. Let me aknow if any problems. You need to add a Ref to "System.Configuration" and add namespace "System.Configuration;" NB: No need to load .config files manually. Application will automatically recognize it by using below classes. Configfile part Method for Runtime Modification public static void UpdateToolTypeConfiguration(string toolType) { Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None); //Assigning new value to ToolType section config.AppSettings.Settings["ToolType"].Value = toolType; config.Save(ConfigurationSaveMode.Modified); ConfigurationManager.RefreshSection("appSettings"); } Calling method UpdateToolTypeConfiguration("AnalysisTool");

Hirendra Sisodiya · Answer

Hello Giorgio App.config file is a xml file, you can write it on run time for example if you can change any key value of app.config you can try this function: public static void WriteSetting( string key, string value) { // load config document for current assembly XmlDocument doc = doc.Load(Assembly.GetExecutingAssembly().Location + ".config" ); // retrieve appSettings node XmlNode node = doc.SelectSingleNode( "//appSettings" ); if (node == null ) { throw new InvalidOperationException ( "appSettings section not found in config file." ); } try { // select the 'add' element that contains the key XmlElement elem = (XmlElement)node.SelectSingleNode( string .Format( "//add[@key='{0}']" , key)); if (elem != null ) { // add value for key elem.SetAttribute( "value" , value); } else { // key was not found so create the 'add' element // and set it's key/value attributes elem = doc.CreateElement( "add" ); elem.SetAttribute( "key" , key); elem.SetAttribute( "value" , value); node.AppendChild(elem); } doc.Save(Assembly.GetExecutingAssembly().Location + ".config" ); } catch { throw ; } } thanks Please mark as answere if it helps

Lalit M · Answer

You can do it at Run time show here will help . http://chiragrdarji.wordpress.com/2008/09/25/how-to-change-appconfig-file-run-time-using-c/ http://generally.wordpress.com/2007/09/27/using-appconfig-for-user-defined-runtime-parameters/ Read/Write App.config

gunjan arora · Answer

the code is running fine but I the changes are not visible in app.config during debug.

Hirendra Sisodiya · Answer

Hello Giorgio you can use my code in window application ..and ' appSettings' is just a node name. thanks

Jaish Mathews · Answer

Hi, Want to say some thing about Settings. This is normallu using to keep static strings, may be a web service path. But string values which may change depends on environment needs to keep in Config file. Because After config file modification, no application rebuild needed. You can use application as like But any change in .Settings need another build to make the changes embedded to the library. .Setting values anre keeping embedded to the library

Sam Hobbs · Answer

I think all the previous replies are more complicated than what the typical application needs. My CSV article shows a very simple use of the app.config file that I think would be typical of many applications. It uses Properties. Settings .Default to get and save settings. Note that in a typical Forms application, there is a Propeties node with a Settings.Settings file. Open that; you can create settings there, which is the app.config file. In the settings, there are two types; Appliation and User. The Application settings are for use by the application but not normally modified by the user.

Gustavo · Answer

Jaish: Thanks, I got it to work.

Gustavo · Answer

Hirendra: I tried yours, its a lot simpler then the others. BUT... the line with doc.Load is stopping the program in being compiled. XmlDocument doc = doc.Load(Assembly.GetExecutingAssembly().Location + ".config" ); BTW: Is this for a web app or a C# windows? reason I ask is that I saw this line: XmlNode node = doc.SelectSingleNode( "//appSettings" ); Doesnt the "appSettings" mean its for a web app? I am a newbe so I am probably wrong. I need it for a Windows Application.

Gustavo · Answer

Hirendra: Thanks. I am playing around with one of the links that Lalit mentioned. I am not getting it to even thou it looked simple. I will try it fora bit more. If I dont get it to work, I will then look at yours... thanks

Gustavo · Answer

Lalit: Thanks. I already found the first two that you mentioned. The third one I never saw it and I like it better. Thanks you.