Why EnvDTE.ProjectItem.FileCodeModel is Null on Dynamics 365 in VS 2017 project

Question

I am writing code to get the CodeElements from .xpp file in D365 project, but FileCodeModel value is always null

foreach (Project project in applicationObject.Solution.Projects)
 {
                        var projectItems = GetProjectItemsRecursively(project.ProjectItems);
                        foreach (ProjectItem item in projectItems)
                        {
                            if ((item.FileCodeModel != null))
                            {
                                
                                foreach (CodeElement elem in item.FileCodeModel.CodeElements)
                                {
                                    
                                }
                            }

                        }
                    }

Answer 1

According to the documentation for ProjectItem.FileCodeModel, "A FileCodeModel object is returned only for project items that are code files and in projects that implement the Visual Studio code model."

Since x++ is a very distant cousin of the .NET family, my guess would be that its files (.xml files that combine code and metadata) are not recognized as code files and/or the D365FO projects do not implement the VS code model.