How to filter ItemGroup in MsBuild based on filename part?

Question

I have an ItemGroup that contains some files (And I have no control on how this list is generated):

Answer 1

You need to use item batching using the % instead of the @. This will work on the items one by one instead of including them all at the same time. You had the condition right, which I assume you found somewhere else.

<ItemGroup>
  <FilteredFiles Include="%(AllFiles.Identity)" Condition="$([System.Text.RegularExpressions.Regex]::IsMatch(%(Filename), '\.Tests\.dll'))"/>
</ItemGroup>