如何将值从页面传递到控制器？

Question

I'm using MVC with Razor and C#. I would like to update an element... a counter with ajax. Here is my code:

@model Domain.CounterObject
@using (Ajax.BeginForm("Count", "CounterObject", new AjaxOptions { HttpMethod = "POST", UpdateTargetId = "my-control" }))
{
    <div id="my-control" class="bid-object">
        <div>
            <span class="title">@Html.Encode(Model.Title)</span>
        </div>
        <div>
            <span class="display">@Html.Encode(Model.GetFinalDate())</span>
        </div>
        <div>
            <span class="display">@Html.Encode(Model.GetValue())</span>
        </div>
        <div>
            <input type="submit" value="Count" />
        </div>
    </div>
}

In my controller I have this code:

[HttpPost]
        public PartialViewResult Count(CounterObject counter)
        {
            // Special work here
            return PartialView(counter);
        }

The problem is that my CounterObject counter I receive in my Count method is always null. How can I pass a value from my page to the controller?

Answer 1

You'll have to define a input field with a name and id that the ModelBinder can then Bind to your CounterObject.

You could use @Html.EditorForModel once and then inspect the generated Html to see what kind of name/id pairs it is generating. With those you can go on and handcraft your Html if you wanted to.

Answer 2

use

<span class="title">@Html.Encode(Model.Title)</span>
<div class="editor-field">@Html.EditorFor(Model => Model.Title)<div>
//For other fields

In this way you can bind to your object.

Answer 3

I receive in my Count method is always null

First of all you are not submitting anything from the form then how does the binding happens? If the user is not allowed to edit the values but still you want to submit them through the form then you have to use hidden fields along with them.

For ex.

<div>
   <span class="title">@Html.Encode(Model.Title)</span>
   @Html.HiddenFor(m => m.Title)
</div>

Note that the hidden fields should have the same names as the properties to make the binding happen successfully.

It is better to have properties in the Model that store the GetFinalDate() and GetValue() results so you can easily bind the things like in Title .