Visual Studio 2015解决方案资源管理器操作：UIHierarchy与IVsHierarchy

Question

I am building a custom VS2015 Extension (VSIX package). My primary task is manipulations over the solution explorer like these:

1. Appending existing projects to solution
2. Removing projects from solution
3. Loading/unloading projects
4. Enumerating solution items, not only projects but also solution folders, unloaded projects, non-project items.

I have found some samples and most of them use one of the three common strategies:

1. EnvDTE.Solution , EnvDTE.Project and so on.
2. EnvDTE.UIHierarchy and the like.
3. Microsoft.VisualStudio.Shell.Interop.IVsSolution and IVsHierarchy

I can see that the first one is the most poor in terms of covered scenarios. What I cannot figure out is the difference between the last two. Which one should I dive in having my tasks in mind? What`s the concept behind them?

Answer 1

They are both interfaces implemented by the com solution object. Check out the msdns to see the difference in methods.

https://msdn.microsoft.com/en-us/library/microsoft.visualstudio.shell.interop.ivssolution.aspx

https://msdn.microsoft.com/en-us/library/microsoft.visualstudio.shell.interop.ivshierarchy.aspx

UIHierarchy is an interface to the tool window (any window with nodes, not just the solution explorer) that has a hierarchy in it and comes from the VSSDK whereas the IVs interfaces are coming in directly from interop and represent the actual items in the view.

For what you are saying the IVsSolution is the most direct interface. All IVsSolutions are also IVsHierarchy but any node in the solution explorer is a hierarchy but obviously not a solution.