Question

I have a ModelA model and a strongly typed view ViewA which is typed to ModelA. As you know if you declare an action say ‘ActionAPost’ with a signature like this:

[HttpPost]
public ActionResult ActionAPost(ModelA mod) {
  // code
}

It will bind the values setted on the form to ModelA instance in this case mod. I want to do something like this:

ViewA:

@ModelAInstance.SomeAttr = ViewBag.SomeAttr;

Assign some value staticaly to the model attribute that will be processed by the post action.

Edit:

The value is set on ViewBang previously.

Answer 1

So in the view have a hidden element where the name attribute reflects the object path of the model and property. This way it will bind back to your POST action how you want it

Example:

<input type="hidden" name="SomeAttr" value="@ViewBag.SomeAttr" />

With Razor and the ViewBag value

Set the value in the Model in your GET request then with razor:

@Html.Hidden("SomeAttr", (object)ViewBag.SomeAttr);

@Html.HiddenFor(m => m.SomeAttr, new { value = ViewBag.SomeAttr });