IVsHierarchy hierarchy; Guid guid; hierarchy = GetSolutionHierarchy(); hierarchy.GetGuid(VSITEMID.Root, out guid);
IVsHierarchy hierarchy; Guid guid; uint itemid; hierarchy = GetProjectHierarchy(); itemid = GetItemIdOfProjectItem("MyFile.cs"); hierarchy.GetGuid(itemid, out guid);In this example, we first get the hierarchy object representing a project by calling the `GetProjectHierarchy` method. Then we use the `GetItemIdOfProjectItem` method to get the item ID of a specific project item (in this case, a C# file named "MyFile.cs"). Finally, we call the `GetGuid` method on the hierarchy object, passing in the item ID to get the GUID of the project item. Based on the IVsHierarchy interface and the methods used in the examples, it is likely that this code is part of the Visual Studio SDK package library, which provides tools and APIs for developing extensions for Visual Studio.