c# - The extern alias 'xxx' was not specified in a /reference option

Question

I have two assemblies that unfortunately define the same type in the same namespace. I'm trying to use a an extern alias to work around the problem. In the Visual Studio IDE I have set the "Aliases" property of the reference to my alias. This is supposed to change the C# compiler command line to be something like this:

/reference:MyAlias=MyAssembly.dll

But it doesn't actually do that. The Visual Studio IDE seems to just ignore the Aliases property setting on the reference. So when I go and add the line extern alias MyAlias; at the top of my C# code file I get the error that the alias was not specified in a /reference option to the compiler. I can't figure out what I am doing wrong. Any ideas?

Answer 1

I have the same problem and I was able to reproduce the issue.

It turns out reference aliases are ignored on projects containing xaml files which has an xmlns definition to the output assembly like xmlns:local='clr-namespace:TestProject'.

If you think this is your case as well, please vote up my bug report at Microsoft Connect.

EDIT: There is a suggested workaround in the link above which requires editing the project file manually. In order for this to work, I had to give full path of the assembly. Add the following instructions to the end of your project file:

<Target Name="solveAliasProblem" >
<ItemGroup>
 <ReferencePath Remove="FullPath.dll"/>
 <ReferencePath Include="FullPath.dll">
    <Aliases>ourAlias</Aliases>
 </ReferencePath>
</ItemGroup>
</Target>
<PropertyGroup>
    <CoreCompileDependsOn>solveAliasProblem;$(PrepareResourcesDependsOn)</CoreCompileDependsOn>
</PropertyGroup>