Hi Marco,
It would help if you post the code that is producing this. I'm going to assume you need to remove the last comma that is added using a loop that puts a comma at the end of a string on each iteration. To resolve the extra comma that results, you can add(use whatever variable name you are using now for "strDataCellMembers"):
strDataCellMembers = strDataCellMembers.TrimEnd(",", c)
Often a better approach is to create a List(Of String) and add the datacell member scripts to the list in your loop. Then add the commas like this:
Dim strDataCell As String = String.Join(",", lstDataCellElements)
This approach eliminates the need to manage the last extra comma that looping and appending a string or stringbuilder has.