MVC - change model's value in view on post [closed]

Question

I have view which displays some data from model. I have submit button which onClick event should change model's value and I pass model's with different values but my values in TextBoxFor stay the same as they were on page load. How can I change them?

Answer 1

That's how HTML helpers work and it is by design. They will first look in the POSTed data and after that in the model. So for example if you have:

<% using (Html.BeginForm()) { %>
    <%= Html.TextBoxFor(x => x.Name) %>
    <input type="submit" value="OK" />
<% } %>

which you are posting to the following action:

[HttpPost]
public ActionResult Index(SomeModel model)
{
    model.Name = "some new name";
    return View(model);
}

when the view is redisplayed the old value will be used. One possible workaround is to remove the value from the ModelState:

[HttpPost]
public ActionResult Index(SomeModel model)
{
    ModelState.Remove("Name");
    model.Name = "some new name";
    return View(model);
}