'IsNot' operand of type 'typename' can only be compared to 'Nothing', because 'typename' is a nullable type
A variable declared as nullable has been compared to an expression other than Nothing using the IsNot operator.
Error ID: BC32128
To correct this error
To compare a nullable type to an expression other than Nothing by using the IsNot operator, call the GetType method on the nullable type and compare the result to the expression, as shown in the following example.