IsNothing()
Here are 4 reasons from the article IsNothing() VS Is Nothing
Most importantly, IsNothing(object)
has everything passed to it as an object, even value types! Since value types cannot be Nothing
, it’s a completely wasted check.
Take the following example:
Dim i As Integer
If IsNothing(i) Then
' Do something
End If
This will compile and run fine, whereas this:
Dim i As Integer
If i Is Nothing Then
' Do something
End If
Will not compile, instead the compiler will raise the error:
'Is' operator does not accept operands of type 'Integer'.
Operands must be reference or nullable types.
IsNothing(object)
is actually part of part of the Microsoft.VisualBasic.dll
.
This is undesirable as you have an unneeded dependency on the VisualBasic library.
Its slow - 33.76% slower in fact (over 1000000000 iterations)!
Perhaps personal preference, but IsNothing()
reads like a Yoda Condition. When you look at a variable you're checking it's state, with it as the subject of your investigation.
i.e. does it do x? --- NOT Is x
ing a property of it?
So I think If a IsNot Nothing
reads better than If Not IsNothing(a)