Updating the value of a keyword by Core Service in SDL Tridion 2013

Question

I am trying to update the value of a keyword by using Core service in SDL Tridion 2013. On saving the item with new value by the following code:

 Client.CheckOut(item.Id, false, new ReadOptions());
 item = Client.Save(item, new ReadOptions());
 Client.CheckIn(item.Id, true, "Scripted Update", new ReadOptions());
 Log.Info($"Successfully updated Item {item.Id}");

I get the following exception. Any idea why this is happening and how can I resolve this?

System.ServiceModel.FaultException`1 was unhandled
  HResult=-2146233087
  Message=Unable to cast object of type 'Tridion.ContentManager.ContentManagement.Keyword' to type 'Tridion.ContentManager.ContentManagement.VersionedItem'.
  Source=mscorlib
  StackTrace:
    Server stack trace: 
       at System.ServiceModel.Channels.ServiceChannel.HandleReply(ProxyOperationRuntime operation, ProxyRpc& rpc)
       at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)
       at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
       at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)
    Exception rethrown at [0]: 
       at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
       at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
       at Tridion.ContentManager.CoreService.Client.ICoreService.UndoCheckOut(String id, Boolean permanentLock, ReadOptions readBackOptions)
       at Tridion.ContentManager.CoreService.Client.CoreServiceClient.UndoCheckOut(String id, Boolean permanentLock, ReadOptions readBackOptions)
       at BlackBoard.Tridion.Migration.CoreService.Helpers.CoreServiceHelper.SaveItem(IdentifiableObjectData item) in C:\Code\BBMigrationTool\BlackBoard.Tridion.Migration.CoreService\Helpers\CoreServiceHelper.cs:line 77
       at BBMigrationTool.Actions.MigrateAction.ProcessKeywordMigration(ICoreServiceHelper helper, String language, CategoryKeyword categoryKeyword) in C:\Code\BBMigrationTool\BBMigrationTool\Actions\Migrate.cs:line 58
       at BBMigrationTool.Actions.MigrateAction.Invoke(ICoreService client) in C:\Code\BBMigrationTool\BBMigrationTool\Actions\Migrate.cs:line 35
       at BBMigrationTool.Program.Main(String[] args) in C:\Code\BBMigrationTool\BBMigrationTool\Program.cs:line 77
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: 

Answer 1

Take a look at the class hierarchy in the API doc. Note: Keywords and VersionedItems are both RepositoryLocalObjects, but not all RepositoryLocalObjects are VersionedItems. Take a look in the CM GUI, you'll notice that you don't have versions on Keywords.

So I would suspect that the line where you make the assignment to the 'item' variable is what's causing the problem:

 item = Client.Save(item, new ReadOptions());

My guess is that above the code you showed you declared item as a type which is a VersionedItem (e.g. a Component), Page, Schema, Template), but are now trying to cast it as a Keyword.

Answer 2

As it turned out, Keyword is not versioned. So, the exception is the result of Client.CheckOut(item.Id, false, new ReadOptions()); line. To solve this problem, you just need to separate checkin and checkout commands for items that are not versioned.

Answer 3

The CheckOut (and CheckIn) method signature in CoreService returns a VersionedItemData, as shown below.

VersionedItemData CheckOut(
    string id,
    bool permanentLock,
    ReadOptions readBackOptions
)

If you try to checkout(or checkin) a Keyword (KeywordData) which does not inherit from VersionedItemData you will get an exception.

Instead just do:

 item = Client.Save(item, new ReadOptions());
 Log.Info($"Successfully updated Item {item.Id}");

More details can be found in the API reference guides here