MVC 3: Use a VERY custom format for a Date with automapping on server-side - asp.net-mvc-3

Question

I have a very confusing problem, and I am able to solve it, but there has to be a Out-Of-The-Box-Solution.
The situation is as following:
An user inputs on the client-side a date (i.e. with a date-picker) which outputs the following value to the textbox:
Mi 22.02.2012 (KW 8)
I have a Button which posts my form with this textbox to an controller-action.
Let's say you have the following controller action which takes a MyType as Parameter
[HttpPost]
public ActionResult Create(MyType model)
{
//model.Date is always null
//(or in case the DateTime is not Nullable<T>, the value is DateTime.Min
}
public class MyType
{
public DateTime? Date { get; set; }
}
The question is simple:
How do I map the input to the DateTime?
I do not want to add properties to my class like in the following example:
public class IDontWantThis
{
public DateTime? Date { get { /* Some custom string parsing with DateText */ } }
public string DateText { get; set; } //this would be the auto-mapped property
}

Answer 1

How a date is displayed in the view is of no concern to the controller.
I would add a hidden field with the name of the property you want the datetime to map on the viewmodel (Date). On the client, using javascript, you can format this date any way you want, as long as the hidden field contains the datetime you need to work with.
So let the datepicker store the selected date twice, once with your weird date formatting for display and another time in a hidden field in a common format the modelbinder will understand.

Answer 2

This is what ViewModels are for. I understand that you don't want your domain Model to include a DateText member, but you really should consider something like this:
public class MyType
{
public DateTime? Date { get; set; }
}
public class MyTypeViewModel
{
public MyType MyType { get; set; }
public string DateText { get; set; }
}
What your requirement is one of the main points that makes ViewModels so powerful. Using an intermediate class between your View and your Model to link them together. This way, you won't have any trace of "formatting" data in your Model (MyType).