What am I misunderstanding about how Html.TextBoxFor works

Question

I\'m just trying to get back into .NET MVC with the new release and I can\'t get my head round the way may view is binding to the DataModel.

I have a model with a pr

Answer 1

Because HTML helpers read the value from the ModelState and not from the model. In order the change that behavior you'll need to work with the ModelState as well.
(see: Changing model’s properties on postback)

Answer 2

This should work for the first two:

<%= Html.TextBox("first_name", x => x.first_name)%>
<%= Html.TextBoxFor(model => model.first_name) %> 

Answer 3

You need to clear your model state so your code would look something like:

[HttpPost]
public ActionResult Register(Registration model)
{
    ModelState.Clear();
    model.first_name = "Steve";
    return View(model);
}