Gets the first item from an item group.

getfirstitem.targets

<?xml version="1.0" encoding="utf-8"?>
<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <UsingTask TaskName="GetFirstItem" TaskFactory="CodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v12.0.dll">
    <ParameterGroup>
      <Items ParameterType="Microsoft.Build.Framework.ITaskItem[]" Required="true" />
      <FirstItem ParameterType="System.String" Output="true" Required="false" />
    </ParameterGroup>
    <Task>
      <Using Namespace="System.Linq"/>
      <Code Type="Fragment" Language="cs">FirstItem = Items.First().ItemSpec;</Code>
    </Task>
  </UsingTask>
  
  <Target Name="UseCase">
    <ItemGroup>
        <ItemList Include="first;second;third"/>
      </ItemGroup>
      <GetFirstItem Items="@(ItemList)">
        <Output TaskParameter="FirstItem" PropertyName="FirstItemProperty"/>  
      </GetFirstItem>
      <Message Text="First item is: $(FirstItemProperty)" />
  </Target>
</Project>