c# 對象，IntPtr互轉

        struct aa
        {
            public string a;
            public string b;
        }
            aa p = new aa();
            p.a = "1";
            p.b = "1";
            //對象轉IntPtr
            var handle = GCHandle.Alloc(p);
            var ptr = GCHandle.ToIntPtr(handle);
            //IntPtr轉對象
            var a = GCHandle.FromIntPtr(ptr)
                .Target;
            handle.Free();