VS2010 custom build tool for generating .h file

I'm trying to integrate a custom build tool in VS2010 that generates a .h-file from a source file. I've created a .xml, .targets and .props for the step. The XML is mostly copy-pasted from the MASM-file and ends with:

<ItemType Name="FOO" DisplayName="Foo compiler" />
<FileExtension Name="*.foo" ContentType="FOO" />
<ContentType Name="FOO" DisplayName="Foo compiler" ItemType="FOO" />

This maps all my .foo files to the Foo compiler that's defined in the .props:

<?xml version="1.0" encoding="utf-8"?>
<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <ItemGroup>
    <PropertyPageSchema Include="$(MSBuildThisFileDirectory)$(MSBuildThisFileName).xml" />
    <AvailableItemName Include="FOO">
      <Targets>FooCompile</Targets>
    </AvailableItemName>
  </ItemGroup>
  <UsingTask TaskName="FOO" TaskFactory="XamlTaskFactory" AssemblyName="Microsoft.Build.Tasks.v4.0">
    <Task>$(MSBuildThisFileDirectory)$(MSBuildThisFileName).xml</Task>
  </UsingTask>
  <Target Name="FooCompile" BeforeTargets="$(FOOBeforeTargets)" AfterTargets="$(FOOAfterTargets)" Condition="'@(FOO)' != ''" Outputs="%(FOO.Outputs)" Inputs="%(FOO.Identity);%(FOO.AdditionalDependencies);$(MSBuildProjectFile)" DependsOnTargets="_SelectedFiles">
    <Message Importance="High" Text="@(FOO)" />
    <FOO Condition="'@(FOO)' != '' and '%(FOO.ExcludedFromBuild)' != 'true'"
         CommandLineTemplate="%(FOO.CommandLineT开发者_Python百科emplate)"
         OutputFileName="%(FOO.OutputFileName)"
         Inputs="%(FOO.Identity)" />
  </Target>
</Project>

When I compile my project it successfully identifies and compiles my foo files:

1>FooCompile:
1>  apa.foo
1>FooCompile:
1>  banan.foo
1>ClCompile:
1>  test.cpp
1>  main.cpp

My question is why does it print "FooCompile:" once for each file while the ClCompile doesn't? Is there any way to change this?

If I change a cpp file and build, I'll also get this output once for each file, which I want to avoid:

1>FooCompile:
1>Skipping target "FooCompile" because all output files are up-to-date with respect to the input files.
1>FooCompile:
1>Skipping target "FooCompile" because all output files are up-to-date with respect to the input files.

The FooCompile target is using "target batching" which causes the target to iterate once for each item in the array specified for the Outputs attribute, %(Foo). The ClCompile target on the other hand operates using the entire item array @(ClCompile).

You can alter the verbosity of the logger to avoid the messages, specify /v:minimal, but of course you may be filtering out other information as well.