How do I list all the projects in the current solution using EnvDTE?

Question

I've been following MSDN's Hello World guide to developing Visual Studio extensions (this article specifically deals with creating one as a Visual Studio toolbar command).

I am trying to list all projects contained in the current/active solution.

In the auto generated code for the Command template.

I have tried EnvDTE's Solution's Projects property, but it shows zero projects.

There is a ActiveSolutionProjects property as well, but it also shows an empty array.

How is this achieved ?

P.S.: I tried both DTE and DTE2 interfaces since it is confusing understanding which version to use, from the docs. I get a null service for DTE2, so I am going with DTE.

My Solution Explorer looks like:

---

Update: Bert Huijben, from gitter/extendvs, suggested the following, found at the VSSDK Extensibility Samples - but this too does not work (returns 0 elements, both within the constructor and within the callback function):

private Hashtable GetLoadedControllableProjectsEnum()
{
    Hashtable mapHierarchies = new Hashtable();

    IVsSolution sol = (IVsSolution)this.ServiceProvider.GetService(typeof(SVsSolution));
    Guid rguidEnumOnlyThisType = new Guid();
    IEnumHierarchies ppenum = null;
    ErrorHandler.ThrowOnFailure(sol.GetProjectEnum((uint)__VSENUMPROJFLAGS.EPF_LOADEDINSOLUTION, ref rguidEnumOnlyThisType, out ppenum));

    IVsHierarchy[] rgelt = new IVsHierarchy[1];
    uint pceltFetched = 0;
    while (ppenum.Next(1, rgelt, out pceltFetched) == VSConstants.S_OK &&
           pceltFetched == 1)
    {
        IVsSccProject2 sccProject2 = rgelt[0] as IVsSccProject2;
        if (sccProject2 != null)
        {
            mapHierarchies[rgelt[0]] = true;
        }
    }

    return mapHierarchies;
}

Answer 1

To get the EnvDTE.Project objects:

    static private void FindProjectsIn(EnvDTE.ProjectItem item, List<EnvDTE.Project> results)
    {
        if (item.Object is EnvDTE.Project)
        {
            var proj = (EnvDTE.Project)item.Object;
            if (new Guid(proj.Kind) != Utilities.ProjectTypeGuids.Folder)
            {
                results.Add((EnvDTE.Project)item.Object);
            }
            else
            {
                foreach (EnvDTE.ProjectItem innerItem in proj.ProjectItems)
                {
                    FindProjectsIn(innerItem, results);
                }
            }
        }
        if (item.ProjectItems != null)
        {
            foreach (EnvDTE.ProjectItem innerItem in item.ProjectItems)
            {
                FindProjectsIn(innerItem, results);
            }
        }
    }

    static private void FindProjectsIn(EnvDTE.UIHierarchyItem item, List<EnvDTE.Project> results)
    {
        if (item.Object is EnvDTE.Project)
        {
            var proj = (EnvDTE.Project)item.Object;
            if (new Guid(proj.Kind) != Utilities.ProjectTypeGuids.Folder)
            {
                results.Add((EnvDTE.Project)item.Object);
            }
            else
            {
                foreach (EnvDTE.ProjectItem innerItem in proj.ProjectItems)
                {
                    FindProjectsIn(innerItem, results);
                }
            }
        }
        foreach (EnvDTE.UIHierarchyItem innerItem in item.UIHierarchyItems)
        {
            FindProjectsIn(innerItem, results);
        }
    }

    static internal IEnumerable<EnvDTE.Project> GetEnvDTEProjectsInSolution()
    {
        List<EnvDTE.Project> ret = new List<EnvDTE.Project>();
        EnvDTE80.DTE2 dte = (EnvDTE80.DTE2)ServiceProvider.GlobalProvider.GetService(typeof(EnvDTE.DTE));
        EnvDTE.UIHierarchy hierarchy = dte.ToolWindows.SolutionExplorer;
        foreach (EnvDTE.UIHierarchyItem innerItem in hierarchy.UIHierarchyItems)
        {
            FindProjectsIn(innerItem, ret);
        }
        return ret;
    }

Notably recursion is necessary to dig into solution folders.

If you just want the file paths you can do this w/o using DTE:

    static internal string[] GetProjectFilesInSolution()
    {
        IVsSolution sol = ServiceProvider.GlobalProvider.GetService(typeof(SVsSolution)) as IVsSolution;
        uint numProjects;
        ErrorHandler.ThrowOnFailure(sol.GetProjectFilesInSolution((uint)__VSGETPROJFILESFLAGS.GPFF_SKIPUNLOADEDPROJECTS, 0, null, out numProjects));
        string[] projects = new string[numProjects];
        ErrorHandler.ThrowOnFailure(sol.GetProjectFilesInSolution((uint)__VSGETPROJFILESFLAGS.GPFF_SKIPUNLOADEDPROJECTS, numProjects, projects, out numProjects));
        //GetProjectFilesInSolution also returns solution folders, so we want to do some filtering
        //things that don't exist on disk certainly can't be project files
        return projects.Where(p => !string.IsNullOrEmpty(p) && System.IO.File.Exists(p)).ToArray();
    }

Answer 2

Unfortunately could not find any working solution here, decided to post my own solution:

/// <summary>
/// Queries for all projects in solution, recursively (without recursion)
/// </summary>
/// <param name="sln">Solution</param>
/// <returns>List of projects</returns>
static List<Project> GetProjects(Solution sln)
{
    List<Project> list = new List<Project>();
    list.AddRange(sln.Projects.Cast<Project>());

    for (int i = 0; i < list.Count; i++)
        // OfType will ignore null's.
        list.AddRange(list[i].ProjectItems.Cast<ProjectItem>().Select(x => x.SubProject).OfType<Project>());

    return list;
}

And if you don't know what references / namespaces to add, you can pick up project with source code from here:

https://github.com/tapika/cppscriptcore/blob/2a73f45474c8b2179774fd4715b8d8e80080f3ae/Tools/vsStart/Program.cs#L478

And check namespaces / references.