Checking for Null Value on String

vbNullString is just null (or Nothing). Check to see if value is null (Nothing) first. If it's null, then do not call ToString on it.

Here's some C# code that does this:

String strValue = value == null ? null : value.ToString();

Here's an automatic conversion to VB syntax (not sure how good it is):

Dim strValue As [String] = If(value Is Nothing, Nothing, value.ToString())