Visual Commander script to retarget all loaded Visual Studio projects to a specified .net version (TargetFramework).

RetargetFramework.cs

// Retarget all loaded projects to the .net version specified in "TargetFramework"
// Execute with Visual Commander (https://marketplace.visualstudio.com/items?itemName=SergeyVlasov.VisualCommander)

// **********************************************************
// NOTE: NuGet packages need to be reinstalled post execution
// **********************************************************

using EnvDTE;
using EnvDTE80;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Threading;

public class C : VisualCommanderExt.ICommand
{
	const string FrameworkMoniker = "TargetFrameworkMoniker";
	const string TargetFramework = ".NETFramework,Version=v4.6.2";

	public void Run(EnvDTE80.DTE2 dte, Microsoft.VisualStudio.Shell.Package package) 
	{
		var bw = new BackgroundWorker();
		bw.DoWork += DoWork;
		bw.ProgressChanged += ProgressChanged;
		bw.RunWorkerCompleted += RunWorkerCompleted;
		bw.WorkerReportsProgress = true;
		
		bw.RunWorkerAsync(dte);
	}
	
	private void ReportProgress(EnvDTE80.DTE2 dte, BackgroundWorker bw, string messageFormat, params object[] p)
	{
		var state = new State(dte, string.Format(messageFormat, p));
		bw.ReportProgress(0, state);
		System.Threading.Thread.Sleep(100);
	}		
	
	private void DoWork(object sender, DoWorkEventArgs e)
	{
		var bw = (BackgroundWorker)sender;
		var dte = (EnvDTE80.DTE2)e.Argument;

		var projects = (from p in GetProjects(dte.Solution)
				where p.Properties != null
				let m = p.Properties.Item(FrameworkMoniker)
				where m != null && !m.Value.Equals(TargetFramework)
				orderby p.Name
				select new 
					{
						Project = p,
						TargetFramework = m
					}).ToList();

		ReportProgress(dte, bw, "Converting {0} projects to {1}:\r\n", projects.Count, TargetFramework);

		for (var i = 0; i < projects.Count; i++)
		{
			var item = projects[i];
			var project = item.Project;

			ReportProgress(dte, bw, "[{0}/{1}] {2} ({3})", i+1, projects.Count, project.Name, item.TargetFramework.Value);

			item.TargetFramework.Value = TargetFramework;

			ReportProgress(dte, bw, " ...done.\r\n");
		}		
	}
	
	private void ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)
	{
		var state = (State)e.UserState;
		Log(state.Dte, state.Message);
	}
	
	private void RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
	{   
		var dte = (EnvDTE80.DTE2)e.UserState;
	
		if (e.Cancelled)
		{
			Log(dte, "Operation was canceled");
			return;
		}
		
		if (e.Error != null)
		{
			Log(dte, "An error occurred: {0}", e.Error.Message);
			return;
		}

		Log(dte, "Completed");
	}
	
	public static void Log(EnvDTE80.DTE2 dte, string messageFormat, params object[] p)
	{
		Window window = dte.Windows.Item(EnvDTE.Constants.vsWindowKindOutput);
		OutputWindow outputWindow = (OutputWindow) window.Object;
		outputWindow.ActivePane.Activate();

		outputWindow.ActivePane.OutputString(string.Format(messageFormat, p));
	}		
	
	public static IList<Project> GetProjects(EnvDTE.Solution solution)
	{
		var list = new List<Project>();
		foreach (var item in solution.Projects)
		{
            var project = item as Project;
            if (project == null)
            {
                continue;
            }

            if (project.Kind == ProjectKinds.vsProjectKindSolutionFolder)
            {
                list.AddRange(GetSolutionFolderProjects(project));
            }
            else
            {
                list.Add(project);
            }
        }

        return list;
    }

    private static IEnumerable<Project> GetSolutionFolderProjects(Project solutionFolder)
    {
        List<Project> list = new List<Project>();
        for (var i = 1; i <= solutionFolder.ProjectItems.Count; i++)
        {
            var subProject = solutionFolder.ProjectItems.Item(i).SubProject;
            if (subProject == null)
            {
                continue;
            }

            // If this is another solution folder, do a recursive call, otherwise add
            if (subProject.Kind == ProjectKinds.vsProjectKindSolutionFolder)
            {
               list.AddRange(GetSolutionFolderProjects(subProject));
            }
           else
           {
               list.Add(subProject);
           }
        }
        return list;
    }
	
	public class State
	{
		public State(EnvDTE80.DTE2 dte, string message)
		{
			Dte = dte;
			Message = message;
		}
		
		public EnvDTE80.DTE2 Dte { get; set; }
		public string Message { get; set; }
	}
}