Investigation: Values do not retain in model while posting it from view to controller action in MVC

Scenario: My controller action is passing a model to the view, and displaying the fields on my view.

There are few fields which are non-editable (like, ID, etc), and are only for display purpose, so I have placed them directly on view.

There are few fields in that model which are not required to be displayed at all on view, so I have not placed them on view.

The problem is that, when a user clicks Submit to post the view to controller action, the model does not contain their original value for those fields.

How to fix it?

Fix: When you bind a model by passing it from control action to view, you should bind each and every field of the model in view. This will retain their values during HttpPost.

So if there are some fields you want to display them as read-only, or if you do not want to display them at all, then you should still bind them within view. Its necessary if you are posting the view to a controller action (using HttpPost)

The best way is to use hidden tag, using @Html.HiddenFor helper, if you do not want to display the field.
Or use @Html.DisplayFor helper, if you want to display the field in read-only mode.