Check a null reference

[gxpark]

I'm sure this one is easy...

How do I check if an object contains a Null reference?

Thanks in advance

[gxpark]

easy indeed... with Is Nothing

[Dillinger4]

You might want to take note that IsNull and IsEmpty from VB6 have been declared obsolete in VB.Net. You can now use IsDBNull() which takes an object as a parameter and returns a boolean value indicating wether the variable has been initialized.


You can also work with the DBNull class which is part of the System namespace. Ill give you examples of bolth methods for comparison puposes.

Dim sysNull as System.DBNull
Dim strString as String

If strString is sysNull Then 
  strString = " String is now initialized"
End If

If Not IsDBNull(sysString) Then 
  Debug.WriteLine strString
End If