How to handle null objects in string concatenations in VB.NET?

Question

Dim response As MyClass = obj.ProcessRequest(strRequest)
Msgbox("This is the response message: " & response.Message)

If there is a problem in the ProcessRequest method and it returns null , then the next line will not work and a NullReference exception will be thrown.

What is the easiest way to have response.Message evaluate to an empty string if response is null ?

Answer 1

You may use inline If :

Msgbox("This is the response message: " & If(response Is Nothing, "", response.Message))

but IMO it is more readable to use if .. else clause

Answer 2

& Nothing equates to & "".

So the neatest way IMO is:

Dim response As MyClass = obj.ProcessRequest(strRequest)
Msgbox("This is the response message: " & response?.Message)