MZ-Tools Articles Series: HOWTO Unload/Reload a project from a Visual Studio package

I have created two new articles/samples from a question that I addressed in the StackOverflow forum, about unloading / reloading a project programmatically. Using the automation model (EnvDTE) I knew the answers since many years ago:

DTE.ExecuteCommand(“Project.UnloadProject”)
DTE.ExecuteCommand(“Project.ReloadProject”)

However, that approach requires that the project is selected previously in the Solution Explorer. Furthermore, having migrated my MZ-Tools add-in to a Visual Studio package I am no longer happy when I have to use the old automation model and I am eager to investigate how to do things using native services. Alas, the investigation is never easy. In this case the IVsSolution interface provides the CloseSolutionElement method, which is not intuitive because it serves to unload many things, from the solution to a document, and certainly a project too. And it doesn’t seem to provide a method to reload a project. So, I opened the MSDN documentation for IVsSolution2, IVsSolution3, IVsSolution4, IVsSolution5 and IVsSolution6 interfaces and lo and behold, the IVsSolution4 interface has the answers in the UnloadProject / ReloadProject methods. If you remember, Visual Studio 2012 introduced asynchronous solution loading (something that seemed to start in Visual Studio 2010), so the new IVsSolution4 interface introduced quite a few methods that helps with that area. So, here are the samples:

HOWTO: Unload a project from a Visual Studio Package

HOWTO: Reload a project from a Visual Studio Package

Both methods require the project guid that identifies the project in the solution (not to confuse with the project type guid). You can get the project guid from a IVsHierarchy that represents a project calling the GetProperty method with the __VSHPROPID.VSHPROPID_ProjectIDGuid property. For VS 2010, alas, when the project is unloaded the “hierarchy stub” that represents the unloaded project in the solution doesn’t implement that property (it does in VS 2012 and higher). So, the second article applies to VS 2012 and higher (because it starts with an unloaded project as the initial condition), while the first could apply also to VS 2010.

Finally, for completeness sake, given a IVsHierarchy that represents an unloaded project you can get the unload reason calling the GetProperty method with the __VSHPROPID5.VSHPROPID_ProjectUnloadStatus property, which should return a value of the _VSProjectUnloadStatus enumeration.

2 thoughts on “MZ-Tools Articles Series: HOWTO Unload/Reload a project from a Visual Studio package”

  1. hi
    im yosri 24 years , im a master degree student , i have a problem with visual studio automation (EnvDTE) from an external VBA
    the work consist of
    instanciate VS
    open solution
    open project
    compile and run project
    thank you for helping me

    1. Hi,

      Please continue using the post on the forum MSDN Visual Studio Integrate that you have already open. I already answered some pointers.

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