I am able to reproduce the error you are facing. This is actually expected behavior because ProjectItems.AddFromDirectory() is not implemented for all project types (especially VC++ projects), or not exposed through the DTE automation layer.
As a workaround, instead of using AddFromDirectory(), you’ll need to add the .c and .h files individually using AddFromFile() or AddFromFileCopy() as shown below:
folderPath = 'C:\Users\matte\Desktop\Tesi\file generazione\file generati\';
files = dir(fullfile(folderPath, '*.c'));
files = [files; dir(fullfile(folderPath, '*.h'))];
for k = 1:length(files)
fullPath = fullfile(folderPath, files(k).name);
proj.ProjectItems.AddFromFile(fullPath); % Or AddFromFileCopy if you want a copy
end
Also note that if you're trying to add these to a specific folder inside the project, like proj.ProjectItems.Item("Source Files").ProjectItems.AddFromFile(...), you’ll need to navigate through the project tree.
I hope this helps resolve the issue!
