Is there a constraint that restricts my generic method to numeric types?

Question

Can anyone tell me if there is a way with generics to limit a generic type argument T to only:

• Int16
• Int32

Answer 1

There's no constraint for this. It's a real issue for anyone wanting to use generics for numeric calculations.

I'd go further and say we need

static bool GenericFunction(T value) 
    where T : operators( +, -, /, * )

Or even

static bool GenericFunction(T value) 
    where T : Add, Subtract

Unfortunately you only have interfaces, base classes and the keywords struct (must be value-type), class (must be reference type) and new() (must have default constructor)

You could wrap the number in something else (similar to INullable) like here on codeproject.

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You could apply the restriction at runtime (by reflecting for the operators or checking for types) but that does lose the advantage of having the generic in the first place.