C# generic type constraint for everything nullable

Question

So I have this class:

public class Foo where T : ???
{
    private T item;

    public bool IsNull()
    {
        return item == null;
    }

}
         


        

Answer 1

    public class Foo
    {
        private T item;

        public Foo(T item)
        {
            this.item = item;
        }

        public bool IsNull()
        {
            return object.Equals(item, null);
        }
    }

    var fooStruct = new Foo(3);
        var b = fooStruct.IsNull();

        var fooStruct1 = new Foo(3);
        b = fooStruct1.IsNull();

        var fooStruct2 = new Foo(null);
        b = fooStruct2.IsNull();

        var fooStruct3 = new Foo("qqq");
        b = fooStruct3.IsNull();

        var fooStruct4 = new Foo(null);
        b = fooStruct4.IsNull();