In the database I am using, one table has an ID column for a lookup table (StreamName) but because it is not properly defined as a Foreign Key, the relation was not scaffolded in EF and the key can and does contain illegal IDs (specifically zero). I need to get the column to display an empty cell if the lookup fails. I do not have the option to change the database. I tried this as the Property expression:
(StreamNameID == 0) ? String.Empty : StreamName.Name
However the column always just displays the EF class name for the table underlying the DataGrid. It's the same if I just use StreamName.Name (I copied this usage from another lookup column which was properly defined as a FK and which works). In fact it does this even if there is a correct key value in the row. What is the best approach for this? Do I need to use a template somehow?
In my opinion this should be used as Template - you cannot assign such expression to a Property.