Adding AppSettings to a Sharepoint Web Application Web.Config

I use this code to add key/values to the web.config during installation of features

(using Microsoft.SharePoint.Administration;)

string siteName = "http://moss";
SPSite site = .....;
SPWebApplication webApp = site.WebApplication;
System.Collections.ObjectModel.Collection allModifications= webApp.WebConfigModifications;           

AddNewAppSetting(allModifications,"testkey1","testvalue1");
AddNewAppSetting(allModifications,"testkey2","testvalue2");

SPFarm.Local.Services.GetValue().ApplyWebConfigModifications();

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private void AddNewAppSetting(System.Collections.ObjectModel.Collection allModifications,string name, string value)
{
  SPWebConfigModification modification = new SPWebConfigModification(string.Format
  ("add[@key='{0}']", name), "/configuration/appSettings");
          
  modification.Type =
  SPWebConfigModification.SPWebConfigModificationType.EnsureChildNode;
  modification.Value =  string.Format(CultureInfo.InvariantCulture,string.Format
  ("",name,value) );
           
  if (allModifications.Contains(modification))
  {
    allModifications.Remove(modification);                    
  }
            
  allModifications.Add(modification);
           
}

Sources:

• MSDN
• SkunkWorks