Dump ItemGroups and metadata from msbuild

DumpItems.xml

<!--?xml version="1.0" encoding="utf-8"?-->
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <UsingTask
    TaskName="LogItems"
    TaskFactory="CodeTaskFactory"
    AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v4.0.dll" >
    <ParameterGroup>
      <Items Required="true" ParameterType="Microsoft.Build.Framework.ITaskItem[]" />
      <Metadata ParameterType="Microsoft.Build.Framework.ITaskItem[]" />
      <Importance />
    </ParameterGroup>
    <Task>
      <Using Namespace="System" />
      <Using Namespace="System.Reflection" />
      <Using Namespace="System.Collections.Generic" />
      <Using Namespace="System.Linq" />
      <Using Namespace="Microsoft.Build.Framework" />
      <Code Type="Fragment" Language="cs">
      <![CDATA[
        MessageImportance level = (MessageImportance)Enum.Parse(typeof(MessageImportance), Importance ?? "Normal", false);
        bool dumpAllMetadata = true;
        bool dumpNoMetadata = false;

        if (Metadata != null && Metadata.Count() == 1)
        {
          if ("All".Equals(Metadata[0].ItemSpec, StringComparison.OrdinalIgnoreCase)) {
            dumpAllMetadata = true;
            dumpNoMetadata = false;
          } else if ("None".Equals(Metadata[0].ItemSpec, StringComparison.OrdinalIgnoreCase)) {
            dumpAllMetadata = false;
            dumpNoMetadata = true;
          } else {
            dumpAllMetadata = false;
            dumpNoMetadata = false;
          }
        }

        foreach(var item in Items)
        {
          Log.LogMessage(level, "Item: {0}", item.ItemSpec);
          if (dumpNoMetadata) { continue; }
          foreach(string mdName in item.MetadataNames)
          {
            if (dumpAllMetadata || Metadata.Any(x => x.ItemSpec.Equals(mdName, StringComparison.OrdinalIgnoreCase))) {
              Log.LogMessage(level, "\t{0} = {1}", mdName, item.GetMetadata(mdName));  
            }
          }          
        }
      ]]>
      </Code>

    </Task>
  </UsingTask>
</Project>