Example for adding or removing a webconfig modification in SharePoint 2010.
private void UpdateWebConfig(string name, string path, string owner, SPWebConfigModification.SPWebConfigModificationType type, string value, SPWebApplication app, bool removeModification)
{
if (removeModification) {
var removals = app.WebConfigModifications.Where(item => item.Name == name).ToList();
foreach (var item in removals) {
app.WebConfigModifications.Remove(item);
}
} else {
SPWebConfigModification modification = new SPWebConfigModification();
modification.Name = name;
modification.Path = path;
modification.Owner = owner;
modification.Sequence = 0;
modification.Type = type;
modification.Value = value;
app.WebConfigModifications.Add(modification);
}
app.Update();
app.Farm.Services.GetValue<SPWebService>().ApplyWebConfigModifications();
}Usage:
UpdateWebConfig(
"add[@name='handlerName']",
"configuration/system.webServer/handlers",
"FeatureName",
SPWebConfigModification.SPWebConfigModificationType.EnsureChildNode,
"<add name='handlerName' verb='*' path='service.axd' type='Namespace, Assembily, Version=1.0.0.0, Culture=neutral, PublicKeyToken=0x0xx00000x00xx0' />",
webApplication,
false
);