.csproj multiple hint paths for an assembly

Question

I'm packaging example code for an SDK distribution. In the distribution, the relative path from code to the SDK assemblies is different from the build machine. For example:

Distribution

csharp/bin/assembly.dll
example/ex1/ex1.csproj

Build Machine

foo/sdk/csharp/bin/assembly.dll
bar/baz/quux/ex1/ex1.csproj

Assume that I can't move anything. Is there a way I can instruct ex1.csproj to look in both

../../csharp/bin/ and ../../../../foo/sdk/csharp/bin/ for assembly.dll?

In C++ I'd put the dependency path in a standalone property sheet and distribute a different version with the SDK. But C# doesn't have property sheets, and I don't want to maintain two versions of the full project.

I've seen this question which states that I can't use multiple <HintPath> tags, so I'm looking for another way to approximate the same behavior.

Solution 1

I found a hacky solution that works for my case, where the parent directory is guaranteed to be different somewhere up the tree:

<Choose>
  <When Condition="Exists('$(MSBuildProjectDirectory)\..\..\example')">
    <ItemGroup>
      <Reference Include="Assembly ...">
        <HintPath>..\..\csharp\bin\assembly.dll</HintPath>
      </Reference>
    </ItemGroup>
  </When>
  <Otherwise>
    <ItemGroup>
      <Reference Include="Assembly ...">
         <HintPath>..\..\..\..\..\foo\sdk\csharp\bin\assembly.dll</HintPath>
      </Reference>
    </ItemGroup>
  </Otherwise>
</Choose>

Solution 2

The simplest way since only ONE HintPath can be used is to use the all-so-nice Condition attribute like this:

<Reference Include="TheAssembly">
    <HintPath Condition="Exists('..\My\Assembly\Path')">..\My\Assembly\Path\TheAssembly.dll</HintPath>
    <HintPath Condition="Exists('..\..\My\Assembly\Path')">..\..\My\Assembly\Path\TheAssembly.dll</HintPath>
    <HintPath Condition="Exists('..\..\..\My\Assembly\Path')">..\..\..\My\Assembly\Path\TheAssembly.dll</HintPath>
    <HintPath Condition="Exists('..\..\..\..\My\Assembly\Path')">..\..\..\..\My\Assembly\Path\TheAssembly.dll</HintPath>
    <HintPath Condition="Exists('..\..\..\..\..\My\Assembly\Path')">..\..\..\..\..\My\Assembly\Path\TheAssembly.dll</HintPath>
    <HintPath Condition="Exists('..\..\..\..\..\..\My\Assembly\Path')">..\..\..\..\..\..\My\Assembly\Path\TheAssembly.dll</HintPath>
    <HintPath Condition="Exists('..\..\..\..\..\..\..\My\Assembly\Path')">..\..\..\..\..\..\..\My\Assembly\Path\TheAssembly.dll</HintPath>
    etc...
</Reference>

So the answer to the question would be this:

<Reference Include="assembly">
    <HintPath Condition="Exists('..\..\csharp\bin')">..\..\csharp\bin\assembly.dll</HintPath>
    <HintPath Condition="Exists('..\..\..\..\foo\sdk\csharp\bin')">..\..\..\..\foo\sdk\csharp\bin\assembly.dll</HintPath>
</Reference>

If multiple conditions matches, the last one will be used.

Solution 3

Add the secondary path as follows to the general property group. in the csproj file

<PropertyGroup>
    <ReferencePath>..\..\..\..\..\foo\sdk\csharp\bin\</ReferencePath>
    ...
</PropertyGroup>

The ReferencePath property is intended to be specified when executing MsBuild, but it will work fine like this.

Solution 4

I am using this solution without any problem:

<Reference Include="log4net">
  <HintPath>
     $(SolutionDir)packages\log4net.2.0.8\lib\net45-full\log4net.dll
  </HintPath>
</Reference>

Got it from here: use hint paths relative answer from LeonidVasilyev

View more solutions

Comments

[japreiss]

This is too complicated. The SDK user must be able to unzip the SDK, open the example project, and compile it with no extra steps.

[Axarydax]

I would still go along the same way - using user's SDK path as reference and do some folder links trickery on build machine to make it run there too

[Axarydax]

That means I'd create a directory link ..\..\csharp to point to ..\..\..\..\foo\sdk, so the ex1.csproj would find the assembly in ..\..\csharp

[John Dyer]

I'm using Visual Studio 2012 and it's storing the reference path details in the csproj.user file not csproj What version of Studio are you using or is there a setting somewhere to get Studio to put the reference path details in the csproj file?

[Gurpreet]

how about this codeproject.com/Articles/184718/…

[Wolf5]

Yup. I think that would work as well. Same answer as Filip has written.

[Steven Liekens]

I think this breaks as soon as more than one condition is truthy. That is, when both csharp\bin and ..\..\foo\sdk\csharp\bin exist.

[Wolf5]

I does not break if that was to happen, as Visual Studio takes the first or last. It ignores that you have multiple as if the extras did not exist.

[rob]

Down-voting as this only updates the csproj.user and the path is expected to exist on the developers machine when using GUI shown.

[berkus]

<HintPath Condition=""> from Wolf5 answer below is betterer.

[ansar]

HI , excellent i was looking for the same solution , i need one more info like can we check if a variable value is true in some text file then load the one dll and if false the other dll ?

[Wolf5]

To do that you would probably need to create a function in your .csproj using the <UsingTask> tag that ouputs is true or false. Then run it it before the <Reference> task and check on its output in the Condition attribute. (example of usingtask: stackoverflow.com/questions/13548851/…)

[ansar]

@Wolf5 can you please have a look at stackoverflow.com/questions/34059733/…

[Optimus1]

Amazing. Been having so much trouble with a project that was shared between multiple solutions. Thanks.

[Peter Bulyaki]

I think it is also worth mentioning that in case more than one such conditions are evaluated as true the LAST true condition in the list of HintPaths will be used by Visual Studio. It looks like that true conditions are overriding each other while they are being processed one by one. I haven't tried it with MSBuild yet but I assume it's the same.

[Al Albers]

Here is a Regex find+replace I used to accommodate NuGet references in projects that are shared in two solutions, where the second solution is nested in a subfolder of the first solution: --- find: ^(.*?)<HintPath>(.*?)packages(.*?)</HintPath>$ --- replace: $1<HintPath Condition="Exists('..\packages')">..\packages$3</HintPath>\n‌​$1<HintPath Condition="Exists('..\..\packages')">..\..\packages$3</HintP‌​ath>

[Karl Essinger]

@berkus I think this answer is better for larger projects with a lot of references. You can add and remove references without having to add the directory condition each time and it looks cleaner imo.

[Joe Lau]

This answer is better for my scenario that some fundamental library-projects (eg text-processing libraries) are referenced by both main-level project (eg webapp) and second-level projects (eg data-layer libraries)