How to check if a Datatable is Null or Nothing

Question

How can I check if a DataTable has never been set, meaning it will be Null or Nothing? I don't mean an empty DataTable.

For example:

Dim dt As DataTable = TryCast(Session("dt"), DataTable)

If dt.Rows.Count <> 0 Then
    'Do something !
End If 

If Session("dt")has never been set or is lost in memory for some reason, dt.Rows.Count <> 0 will throw this exception:

Object reference not set to an instance of an object.

Answer 1

Preferred:

If dt Is Nothing Then ...

• Is-Operator
• Nothing

or (VB6 like)

If IsNothing(dt) Then ...

IsNothing Function