myColumn.Expression= problems

[Rod]

As soon as my code hits

myColumn.Expression = "'abc'" I get the below unhelpful error message.
Whatever I put on the rhs fails.

Any clues much appreciated ,
many thanks

Rod
An unhandled exception of type 'System.Reflection.TargetInvocationException'
occurred in mscorlib.dll
Additional information: Exception has been thrown by the target of an
invocation.
The full code is as below
Dim myColumn As DataColumn = New DataColumn

With myColumn

..DataType = System.Type.GetType("System.String")

..AllowDBNull = False

..Caption = "Full Name"

..ColumnName = "Full Name"

' .Expression = "[Last Name] & ', ' & [First Name]"

..Expression = "'abc'"

End With