How can I add a new property in an already existing xml file?

Question

Hi,

I am working on an application that parses a .csproj file. It needs to add an additional value to the <NoWarn> property if it exists. In the event that the property does not exist I want the application to add this property with its value to the specified parent node. How can I achieve this? I am using LINQ-to-XML to parse the project file.

Answer 1

Untested, but is it something like:

XNamespace ns = @"http://schemas.microsoft.com/developer/msbuild/2003";
XDocument doc = XDocument.Load(path);
var noWarn = (from grp in doc.Descendants(ns + "PropertyGroup")
        from el in grp.Descendants(ns + "NoWarn")
        select el).FirstOrDefault();
if(noWarn==null) {
    var grp = doc.Descendants(ns+"PropertyGroup").First();
    grp.Add(new XElement(ns+"NoWarn", "1234"));
} else {
    noWarn.Value += "; 1234";
}
doc.Save(path);