Question

I have come from WPF (MVVM) background and trying to shift to MVC 2. Is there any pattern in MVC2 where you can use Commanding/Command buttons like <input> which you use to submit the form so that you can hide/disable when you try to Render the View.

In MVVM world, your commands could implement ICommand interface, and it had CanExecute method which was quite useful. I was wondering if there is anything similar in ASP MVC 2 ?

The only way I can think of, is to do it in the View, so that I can check the flag on ViewModel (CanSave) and depending on that show/hide the <input> tag.

Basically I want to have 2 version of the website running, one in Read-Only mode and the other Editing mode.

Let me know if you need any clarification.

Answer 1

ASP.NET MVC does not feature the notion of ‘controls’, as are found in classic ASP.NET and WPF. The foundational blocks of ASP.NET MVC are HTML elements, like <input>, <button> et cetera. Naturally, these don’t offer the functionality you’re looking for (i.e. Implementation of the ICommand Interface).

The scenario that you’re looking at (i.e. two modes of your form) can be (and arguably should be) dealt with at the View level. You’re already facing the right direction: have a ‘CanSave’ property on your Model, and use this in the View to determine what is generated.

Example:

<% if (Model.CanSave)
    { %>
        <p>First Name: <%= Html.TextBox("firstname", Model.firstname) %> </p>
<%  }
    else
    { %>
        <p>First Name: <%=Model.firstname %></p>
<%  } %>

You’ll probably want to check out the DisplayTemplates and EditorTemplates… very handy for this scenario. Brad Wilson does a good job here.

It will help you move to this:

<%= (Model.CanSave) ? Html.EditorFor(x => x.firstname) : Html.DisplayFor(x => x.firstname) %>

…which makes your View clean and nice.