asp.net mvc - MVC4 Razor - @Html.DisplayFor not binding to model

Question

I am trying to find me feet with MVC4 Razor and I'm stuck with this simple problem.

When I use @Html.DisplayFor the model is always sent back as NULL, but when I use @Html.TextBoxFor this model is fully populated, what am I missing?

Thanks in advance

Answer 1

This is a common issue that many people miss in the asp.net mvc framework. Not just the difference in the helpers such as HiddenFor, DisplayFor, TextBoxFor - but how exactly the framework sets up automatically collecting and validating these inputs. The magic is all done with HTML5's data-* attributes. You will notice when looking at the input tag generated that there are going to be some extra properties in the form of data-val, data-val-required, and perhaps some additional data properties for types, for example numerics would be data-val-number.

These data attributes allow the jQuery extension jquery.validate.unobtrusive.js to parse the DOM and then decide which fields to validate or generate error messages.

The actual collection of posted data is reflected from the name property. This is what should map up to the model that is in the c# or vb [HttpPost] method.

Use HiddenFor when you want to provide posted data that the user does not need to be aware of.

Use DisplayFor when you want to show records but not allow them to be editted.

Use TextBoxFor when you want to allow user input or allow the user to edit a field.

EDIT

"the purpose of this view is to enable the user to view the data before submitting it to the database. Any ideas how I can achieve this?"

You could accomplish this with a duo of HiddenFor and DisplayFor. Use HiddenFor to have the values ready to be posted, and DisplayFor to show those values.