ResolveComReference Invalid argument. Parameter "ItemSpec" cannot be null

Question

I am in the process of upgrading a project to .NET 4.0 and I get this error when I try and build the solution: Invalid argument. Parameter "ItemSpec" cannot be null. c:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets 1558 9

Is there a way to find out what is being passed as null to the ResolveComReference task?

Brian Kretzler Brian Kretzler · Accepted Answer · 2011-04-18T19:33:24

Try this; temporarily add the following to the project file that is failing:

<Target Name="DiagnoseNullItems"
   BeforeTargets="ResolveComReferences"
   AfterTargets="ResolveAssemblyReferences">
   <Message Importance="High" Text="COMReference is '@(COMReference)'" />
   <Message Importance="High" Text="COMFileReference is '@(COMFileReference)'" />
   <Message Importance="High" Text="ReferencePath is '@(ReferencePath)'" />
   <Message Importance="High" Text="_ResolveComReferenceCache is '@(_ResolveComReferenceCache)'" />
</Target>

I think that is all of them, unless some of the other $() arguments to that task are also of type ITaskItem. If that doesn't reveal an empty item, do the same for the properties passed to the ResolveComReference task.

ResolveComReference Invalid argument. Parameter "ItemSpec" cannot be null

1 Answers