Powershell – How to use TFS PowerShell to get list of changesets and associated work items

This is indeed confusing. For now a work-around is to grab the items like so:

$items = @(Get-TfsItemHistory . -r -Stopafter 25 | 
           Foreach {$_.WorkItems.Count > $null; $_})

This accesses the WorkItems collection which seems to cause this property to be populated (I know - WTF?). I tend to use @() to generate an array in cases where I want to use the foreach keyword. The thing with the foreach keyword is that it will iterate a scalar value including $null. So the if the query returns nothing, $items gets assigned $null and the foreach will iterate the loop once with $item set to null. Now PowerShell generally deals with nulls very nicely. However if you hand that value back to the .NET Framework, it usually isn't as forgiving. The @() will guarantee an array with with either 0, 1 or N elements in it. If it is 0 then the foreach loop will not execute its body at all.

BTW your last approach - foreach ($item in $items) { ... } - should work just fine.

Take a look at Jacob Ehn's blog post Automatically Merging Work Items in TFS 2010. He wrote a plug in that can be downloaded from codeplex. It will automatically associate the work items that were associated with the merged changesets. So when you merge to Main or Release the work items will be associated with the changesets in those branches, and the work items will be included in the build reports for builds off of those branches. The plug-in is super easy to deploy.