Question

I’ve got a bunch of duplicate code that looks like this:

If mValue is Nothing Return ""
Return mValue.ToUpper

I defined the following extension method to reduce duplicate code:

<System.Runtime.CompilerServices.Extension()>
Public Function EmptyIfNull(this As String) As String
    If String.IsNullOrEmpty(this) Then Return ""
    Return this
End Function

The duplicate code can be re-written as:

Return mValue.EmptyIfNull.ToUpper

Is there a downside to this?

Answer 1

The only downside is that you’re essentially recreating what’s already in the language (the null coalescing operator, or If function, as it’s implemented in VB.NET)

Return If(mValue, "").ToUpper()

Should do what you’re looking for.

As for your extension method, there’s no need to call String.IsNullOrEmpty, as you only need to handle the case where it’s Nothing.