Programmatically building c# webapplications projects gives errors on opening project

Question

I want to build a freshly new added standard ASP (MVC) webapplication programmatically in Visual Studio 2017. I therefore use a console application that uses Microsoft.Build.Evaluation.Project.Build() to open and compile the project. The console application that builds is outlined below. The project that needs to be build is a standard ASP MVC .Net application just generated from the wizard in Visual Studio. In my Visual Studio version 2017 this compiles fine. However if I want to compile it using my application , at opening of the project, it comes up with the error :

Microsoft.Build.Exceptions.InvalidProjectFileException occurred HResult=0x80131500 Message=The imported project "C:\\Program Files (x86)\\MSBuild\\Microsoft\\VisualStudio\\v15.0\\WebApplications\\Microsoft.WebApplication.targets" was not found. Confirm that the path in the declaration is correct, and that the file exists on disk.

Now, if you open the csproj file of the webapplication in notepad it tells you that it wants to find it's imported projects in:

Import Project="$(VSToolsPath)\\WebApplications\\Microsoft.WebApplication.targets" Condition="'$(VSToolsPath)' != ''"

According tot the error it seems to me that the toolspath is "C:\\Program Files (x86)\\MSBuild\\Microsoft\\VisualStudio\\v15.0" However the WebApplications\\Microsoft.WebApplication.targets is located in "C:\\Program Files (x86)\\MSBuild\\Microsoft\\VisualStudio\\v14.0"

A workaround obviously is to copy the WebApplications folder from v14.0 to v15.0. It then compiles happily. But the questions are : Why is a standard generated project pointing to a directory that does not exsist? Why can Visual Studio itself cope with this wrong path? Is there a better solution than to copy the WebApplications folder ?

Here is the code that opens and compiles the web project:

using System;
using Microsoft.Build.Logging;


namespace CompilerApp
{
class Program
{
    static void Main(string[] args)
    {
        //string projectfile = @"C:\temp\CompilerApp\MyCSharp7\MyCSharp7.csproj";

        string projectfile = @"C:\temp\CompilerApp\WebApplication1\WebApplication1.csproj";
        UnloadAnyProject();
        Microsoft.Build.Evaluation.Project p = new Microsoft.Build.Evaluation.Project(projectfile);
        FileLogger loggerfile2 = new FileLogger();
        loggerfile2.Parameters = @"logfile=C:\temp\CompilerApp\myapp.msbuild.log";
        bool buildresult = p.Build(loggerfile2);
        if (buildresult)
        {
            Console.WriteLine("project compiled");
        }
        else
        {
            Console.WriteLine("project not compiled, check {0}", @"C:\temp\myapp.msbuild.log");

        }
        p.Save();
        UnloadAnyProject();


    }

    private static void UnloadAnyProject()
    {
        Microsoft.Build.Evaluation.ProjectCollection projcoll = Microsoft.Build.Evaluation.ProjectCollection.GlobalProjectCollection;

        foreach (Microsoft.Build.Evaluation.Project pr in projcoll.LoadedProjects)
        {
            Microsoft.Build.Evaluation.ProjectCollection mypcollection = pr.ProjectCollection;
            mypcollection.UnloadProject(pr);
        }
    }
}
}

Answer 1

Why is a standard generated project pointing to a directory that does not exsist? Why can Visual Studio itself cope with this wrong path? Is there a better solution than to copy the WebApplications folder ?

I have completely reproduced your problem with your code. But this issue not occurred on the Visual Studio 2015 with the same scripts and Visual Studio compile after test.

After more investigation, I have noticed that the project class of "Microsoft.Build.Evaluation.Project" did not read the correct path of Visual Studio 2017, the toolpath on VS2017 should be C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\Professional\\MSBuild\\Microsoft\\VisualStudio\\v15.‌​0, but I could not check the source code of that project class with ILSpy.

So I have reported this issue to Visual Studio Developer Community (Thanks for your contribution), you can follow with your comments and check the feedback of this issue. I will also follow up this issue, I will send you the latest status of this issue.

https://developercommunity.visualstudio.com/content/problem/45156/the-project-class-of-microsoftbuildevaluationproje.html

Hope this can help you.