lawphotog lawphotog -4 years ago 189
Vb.net Question

How to check if a Datatable is Null or Nothing Vb.net

How can I check if a datatable has never been set ? or Null or Nothing ? I don't mean 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 lost on memory for some reason .. dt.Rows.Count <> 0 will throw ... this exception.

Object reference not set to an instance of an object.


So how do i prevent happening this ?

Thanks a lot ..

L

Answer Source

Preferred:

If dt Is Nothing Then ...

or (VB6 like)

If IsNothing(dt) Then ...

IsNothing Function

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