Calling controller action method directly from Raz

问题:

I looked around and couldn't find an easy solution.

I've tried @GetUserName which doesn't work.
I've tried @ { GetUserName which doesn't work.

There has to be an easy way to call a method from the razor view engine.

It is within a foreach loop.

I need GetUserName(item.userID)

The below code is in my controller:

[ChildActionOnly]
public string GetUserName(int userID)
{
     ProPit_User user = db.ProPit_User.Find(userID);

     return user.username;
}

回答1:

Trying to call a controller action method directly from your view is usually a sign of bad design.

You have a few options, depending on what you are trying to do:

1. Avoid calling the method, instead put the data in your model, and render the model
2. Use Html.RenderAction
3. Put the method in another class and use normal function syntax.

(1) is usually my default approach, often incorporating DisplayTemplates and EditorTemplates

For (3), e.g.

public static class Util
{
    public string MyUtilMethod(int blah)
}

And the view:

@Util.MyUtilMethod(1)

回答2:

Although you can obtain the controller instance from your view, doing so is plain wrong as it violates the whole MVC (and MVVM) paradigm, as the view should not be aware of its controller.

(The only possible reason I can think of where this would be useful would perhaps be for testing the controller from a mocked view, although even here, it should be possible to test the exposed controller functionality directly from unit tests):

@{
    var controller = ViewContext.Controller as MyController;
    var userName = controller.GetUserName(123);
}

The better way to have arrived at this result is for the controller to pre-populate, and pass all the data needed by the View, such as the userName, to a custom ViewModel (as typed by the @model directive at the top of the Razor page), or to the ViewBag dynamic.

回答3:

Other answers say it's bad practice; As with most things, that depends on how you use it.

Microsoft's shared layout as part of the MVC template, _LoginPartial.cshtml calls the SignIn and SignOut methods on the controller directly from the view:

   <li><a asp-area="" asp-controller="Account" asp-action="Signin">Sign in</a></li>

Using the asp-controller and asp-action tag helpers on the hyperlink.