ReSharper warns: “Static field in generic type”

Question

public class EnumRouteConstraint : IRouteConstraint
    where T : struct
{
    private static readonly Lazy> _enumNames; // <         


        

Answer 1

This is not necessarily an error - it is warning you about a potential misunderstanding of C# generics.

The easiest way to remember what generics do is the following: Generics are "blueprints" for creating classes, much like classes are "blueprints" for creating objects. (Well, this is a simplification though. You may use method generics as well.)

From this point of view MyClassRecipe is not a class -- it is a recipe, a blueprint, of what your class would look like. Once you substitute T with something concrete, say int, string, etc., you get a class. It is perfectly legal to have a static member (field, property, method) declared in your newly created class (as in any other class) and no sign of any error here. It would be somewhat suspicious, at first sight, if you declare static MyStaticProperty Property { get; set; } within your class blueprint, but this is legal too. Your property would be parameterized, or templated, as well.

No wonder in VB statics are called shared. In this case however, you should be aware that such "shared" members are only shared among instances of the same exact class, and not among the distinct classes produced by substituting with something else.