Provide user object to every view

Question

How can I provide a user object to every view in ASP.NET MVC without having to create a ViewModel for absolutely every view I have?

When using ASP.NET Membership, I just get a Profile variable in the views with the profile information, but when rolling my own I don't see a way to export that information.

Answer 1

Inherit your ViewModel classes from a master ViewModel with a User property.

Alternatively, you can pass the object in ViewData collection and use an extension method to make it easy to access the object in the view.

Answer 2

Inherit your controllers from base controller. In base controller override OnActionExecuting and set ViewData["UserObject"] here. Something like this:

public class YourBaseController : Controller
{
    protected override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        filterContext.Controller.ViewData["UserObject"] = ...
    }
}

Or create custom filter with the same OnActionExecuting method if you want only certain controllers providing user object to View.

UPDATED:

Create custom Html helper if you dont want to cast ViewData["UserObject"] every time:

public static object RenderUserObject(this HtmlHelper html)
{
    return ((html.ViewData["UserObject"] as UserObject) ?? new UserObject()).ToString();
}

Answer 3

One alternative to having a base ViewModel class, and so having to define a ViewModel class for every view, is to create a generic ViewModel<T> class which exposes a property T InnerModel, or something similar. Then you can pass a ViewModel<Foo> rather than having to explicitly create a FooViewModel class.

Of course if you also need more bespoke ViewModels in places, you can keep the ViewModel base class, and have ViewModel<T> and your bespoke ViewModels extend it.