Prebuild event in Visual Studio replacing $(SolutionDir) with *Undefined*

Question

I believe the problem is documented here moved here and looks like it might be a bug in visual studio, but I'm wondering if anyone knows of a workaround.

Basically I have the following two lines (among other things) one right after the other in the prebuild event.

"C:\WINDOWS\Microsoft.NET\Framework\v3.5\MSBuild.exe" /p:configuration=Release;platform=x86 /t:rebuild "$(SolutionDir)Folder1\Project1.csproj"

"C:\WINDOWS\Microsoft.NET\Framework\v3.5\MSBuild.exe" /p:configuration=Release;platform=x86 /t:rebuild "$(SolutionDir)Folder2\Folder3\Project2.csproj" 

The first one succeeds and the other fails saying that The command ""C:\WINDOWS\Microsoft.NET\Framework\v3.5\MSBuild.exe" /p:configuration=Release;platform=x86 /t:rebuild "*Undefined*Folder2\Folder3\Project2.csproj"" exited with code 1..

Edit:
Figured out the problem was that one of the other projects with the same line as it's prebuild failed, since MSBuild itself doesn't know about the macros.

Anlace

author FYI: link is broken (VS feedback). – Flintshire

Answer 1

I fixed this by replacing all $(SolutionDir) with $(ProjectDir)..\.

It was due to MSBuild running each project independently, and thus not the solution. It worked fine in VS2010, but not on the build server.

Lh

I can't believe this is still a problem in 2015 – Ladonna

hilariously enough, I figured this out too about 2 weeks later than you, but recently forgot I knew the answer and ended up here – Ladonna

this is because it's not a problem, you are building the csproj, not the solution – Priscillaprise

This is still a problem in 2017, this answer corrects the problem. – Gildagildas

This is still a problem in 2021. – Mathias

Guess I'll chime in, still a problem in the year of the lord 2022! – Folkestone

You know what... still a problem in 2023 as well. ;) – Swett

It's still a problem in 2024. Well, it's not 2024 yet, but I'm just leaving this here pre-emptively. – Summertree

The year is 2029. The machines rose from the ashes of the nuclear fire. Their war to exterminate mankind can only be stopped by one program - MSBuild building a single project. – Emelda

Answer 2

Wasted a lot of time to find perfect solution for this problem. Use Directory.Build.props.

In your sln location folder create a file with name Directory.Build.props and put this code inside:

<Project>
 <PropertyGroup>
    <SolutionDir>$(MSBuildThisFileDirectory)</SolutionDir>
 </PropertyGroup>
</Project>

This file will be automagically picked up by all your csproj files and will define (SolutionDir) property.

Conni

Worked for me in VS 2022 – Dorsad

This is a cleaner approach for .NET Core projects. This worked for me in VS 2022 – Intrepid

This is a good approach, especially if you have one solution with multiple projects that you build separately - I do this kind of thing: RUN dotnet publish --no-restore --configuration Release --output /api src/My.Comany/My.Company.Api.csproj, and then another for other csproj's in the same build – Ahmednagar

using .Net 8 and this works for me in command line. – Hydrothermal

Answer 3

Allan's answer is exactly on the right path, but if you want to move to parent directory of the ProjectDir, or the $(ProjectDir)..\ output is going to be a string, you need to perform the 'go to parent directory' operation in msbuild.
Here is how you can achieve this:

<PropertyGroup>
  <TrimmedDir>$([System.IO.Path]::GetDirectoryName($(ProjectDir)))</TrimmedDir>
</PropertyGroup>

This code will set the parent directory path of the ProjectDir to TrimmedDir variable. [System.IO.Path]::GetDirectoryName() performs this operation.

Physicist

Answer 4

Allan's answer had the right idea, but replacing all $(SolutionDir) with $(ProjectDir)..\ did not work for me in VS 2019 16.7.2.

$(ProjectDir)..\ evaluated to the actual ProjectDir with "..\" appended to it, instead of going up one directory.

Instead, I replaced all $(SolutionDir) with $(ProjectDir)\.. and this properly went up one directory.

Mekka

Answer 5

You don't specify if this happens for many projects or just one or two.

If it is only in one or two projects, a temporary workaround might be to replace $(SolutionDir) with the explicit path that Folder2 is located in. For example, something like:

"C:\WINDOWS\Microsoft.NET\Framework\v3.5\MSBuild.exe" /p:configuration=Release;platform=x86 /t:rebuild "C:\AllSolutions\ExampleSolutions\Folder2\Folder3\Project2.csproj"

but with the correct path for your project.

Wan

Answer 6

If you are using only MSBuild and SolutionDir works for some projects but for others not, it's possible that SolutionDir is already defined somewhere in .csproj file of the working projects.

Leptospirosis

Answer 7

I experienced the same problem, in my case the Azure DevOps build pipeline was pointing to the project.csproj file, not the project.sln file.

This resulted in $(SolutionDir) being undefined

Tool a while to figure out; thought I'd share in case others have the same problem.

Dedra