Microsoft.VisualStudio.Project.ProjectFactory.ProjectTypeGuids C# (CSharp) Method

        protected override string ProjectTypeGuids(string file)
        {
            // Load the project so we can extract the list of GUIDs

            this.buildProject = Utilities.ReinitializeMsBuildProject(this.buildEngine, file, this.buildProject);

            // Retrieve the list of GUIDs, if it is not specify, make it our GUID
            string guids = buildProject.GetPropertyValue(ProjectFileConstants.ProjectTypeGuids);
            if(String.IsNullOrEmpty(guids))
                guids = this.GetType().GUID.ToString("B");

            return guids;
        }