sdk: error MSB3105: The item "XXX.cs" was specified more than once in the "Sources" parameter.

While trying to build this PR https://github.com/Microsoft/Docker.DotNet/pull/144 for some reason it is thinking I have a duplicated file in the CI build at AppVeyor.

C:\Program Files\dotnet\sdk\1.0.0-preview5-004460\Roslyn\Microsoft.CSharp.Core.targets(71,5): error MSB3105: The item "AnonymousCredentials.cs" was specified more than once in the "Sources" parameter.  Duplicate items are not supported by the "Sources" parameter. [C:\projects\docker-dotnet\Docker.DotNet\Docker.DotNet.csproj]

1.0.0-preview5-004232 build it just fine. However, the latest version 1.0.0-preview5-004460 throw this error for the same project…

Any ideas?

About this issue

Original URL
State: closed
Created 7 years ago
Comments: 17 (12 by maintainers)

Most upvoted comments

In my case this was a problem as the .csproj.user file had a reference in it as well as the .csproj - so have a look in both files - if it exists in both this can cause the problem

stevescot on May 10, 2017

The latest SDK adds all .cs files by default now without any “Compile” lines.

To fix the error either:

Remove all “Compile” elements from your .csproj and let the SDK add all .cs files to your project automatically. See https://github.com/dotnet/sdk/blob/master/src/Templates/ProjectTemplates/CSharp/.NETCore/CSharpConsoleApplication/ProjectTemplate.csproj for the latest .csproj console app template. Or https://github.com/dotnet/sdk/blob/master/src/Templates/ProjectTemplates/CSharp/.NETCore/CSharpClassLibrary/ProjectTemplate.csproj for the latest class library template for examples.
If you want to control which files are added and don’t want the SDK to automatically added them, set <EnableDefaultItems>false</EnableDefaultItems> property in your .csproj.

This experience will get better once #600 is fixed.

eerhardt on Jan 9, 2017