Question

i wish to create a reusable ASP.NET MVC ViewUserControl which is strongly typed to an enumeration.

Can this be done? When i try it, it says that the strong type the ViewUserControl can accept, can only be of a reference type 🙁

This also means i can’t pass an int as TModel.

Why do i want to do this? I’n various places of my site, i’m displaying a simple image which is dependant upon an enumeration. So instead of copying that logic in multiple places, I wish to have this resuable ViewUserControl and pass in the enumeration.

eg.

public enum AnimalType {    Cat,    Dog }  // .. now code inside the view user control ... switch (animalType) {     case AnimalType.Cat: source = 'cat.png'; text='cute pussy'; break;     ... etc ... }  <img src='<%=Url.Content('~/Images/' + source)%>' alt='<%=text%>' />  

I’m guessin the solution would be to NOT create a strongly typed ViewUserControl (because TModel Type can only be of type class) and then do the following..

<% Html.RenderPartial('AnimalFileImageControl', animalType); %> 

and in the ViewUserControl …

AnimalType animalType = (AnimalType) ViewData.Model;     switch (animalType)     { ... etc ... } 

cheers 🙂

Answer 1

well, you could have:

public sealed class Box<T> where T : struct {     public Box(T value) { Value = value; }     public T Value { get; private set; }     public static explicit operator T(Box<T> item) {         return item.Value; } // also check for null and throw an error...     public static implicit operator Box<T>(T value) {         return new Box<T>(value); } } 

and use Box<int>, Box<MyEnum>, etc – but personally, I expect it would be easier to use an untyped view and simply cast.