TFS "Copy" value from one field to another - tfs

Question

I needed to change a work item field from PlainText -> String.
As I could not change the type on the Work Item, creating a new field and updating it's value from the other field is my approach.
I have tried the "Bulk Edit Selected Work Items.." from TFS/Web but I'm not sure if you may reference another field value in that template.
How may I set [Work Item].[FieldNew].Value = [Work Item].[FieldOriginal].Value ??
Is this even possible without having to use the TFD API?
The reason why I need to change the item field type from PlainText to String is that I want to have a query with a column operator to test if the field has value or not.
For a plainText field the only allowed operator is Contains/Does Not Contain. May I override this to allow a ">" ?

Answer 1

KMoraz's solution does not work for me either, because the HTML field becomes read-only when exported to Excel. Therefore, I used a Powershell script to copy the value of one field into another (just replace the "$wiFieldNewValue" variable with the source field you are copying)
Code reference: Bulk update TFS work items using Powershell
Link to code
Embedded code:
#This script sets a specific field to a specified value for all work items in a specific project
Function LoadTfsAssemblies() {
Add-Type –AssemblyName "Microsoft.TeamFoundation.Client, Version=12.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
Add-Type -AssemblyName "Microsoft.TeamFoundation.WorkItemTracking.Client, Version=12.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
}
##### SETTINGS
#The TFS Team Project Collection to connect to
$tfsUri = "http://tfsserver:8080/tfs/DefaultCollection"
#The TFS Team Project from which to select the work items
$tfsProject = "Test Project"
#The work item type of the work items to update
$wiType = "Test Case"
#The reference name of the field to update
$wiFieldRefName = "Microsoft.VSTS.Common.Priority"
#The value to set the field to
$wiFieldNewValue = "1"
##### END SETTINGS
LoadTfsAssemblies
$tfs = [Microsoft.TeamFoundation.Client.TfsTeamProjectCollectionFactory]::GetTeamProjectCollection($tfsUri)
$tfs.EnsureAuthenticated()
if($tfs.HasAuthenticated)
{
Write-Output "Successfully authenticated to TFS server [$tfsUri]"
$workItemStore = $tfs.GetService([Microsoft.TeamFoundation.WorkItemTracking.Client.WorkItemStore])
$query = "SELECT [System.Id], [System.Title] FROM WorkItems WHERE [System.TeamProject] = '{0}' AND [System.WorkItemType] = '{1}'" -f $tfsProject, $wiType
Write-Output("Using query [$query]")
$workItems = $workItemStore.Query($query)
Write-Output("Going to update [{0}] work items" -f $workItems.Count)
$successCount = 0
$failureCount = 0
ForEach($wi in $workItems) {
Write-Output("Updating work item [{0}]" -f $wi.Title)
try {
$wi.Open()
$wi.Fields[$wiFieldRefName].Value = $wiFieldNewValue
Write-Output("Set field [{0}] to [{1}]" -f $wiFieldRefName, $wiFieldNewValue)
$validationMessages = $wi.Validate()
if($wi.IsValid() -eq $true)
{
$wi.Save()
Write-Output("Successfully updated work item [{0}]" -f $wi.Title)
$successCount++
} else {
Write-Error("Work item is not valid!")
ForEach($validationMessage in $validationMessages)
{
Write-Error("Error: {0}" -f $validationMessage)
}
$failureCount++
}
} catch {
Write-Error("Couldn't set field [{0}] to [{1}] for work item [{2}]" -f $wiFieldRefName,$wiFieldNewValue,$wi.Title)
Write-Error $_
$failureCount++
}
}
Write-Output("Finished!")
Write-Output("Successfully updated: {0}" -f $successCount)
Write-Output("Failed to update: {0}" -f $failureCount)
} else {
Write-Error("Couldn't authenticate to TFS server [$tfsUri]")
}

Answer 2

I'ts possible via Excel.
Create a query with both old and new field columns visible.
Export the query to Excel.
Copy and paste the data from old field column to the new field.
In Excel, from the Team menu click Publish to update the changes in TFS.