asp.net mvc: SQLDateTimeOverflow problem with Entity Framework

I'm trying to update an object, and getting:

SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM. 

There are two fields in the object that are DateTime objects, and they're set with:

  obj.created_date = DateTime.Now;
  obj.modified_date = DateTime.Now;

Except that everything looks reasonable when I view the object:

>? obj.created_date
{1/13/2010 4:02:47 PM}
    Date: {1/13/2010 12:00:00 AM}
    Day: 13
    DayOfWeek: Wednesday
    DayOfYear: 13
    Hour: 16
    Kind: Unspecified
    Millisecond: 817
    Minute: 2
    Month: 1
    Second: 47
    Ticks: 633989953678170000
    TimeOfDay: {16:02:47.8170000}
    Year: 2010
>? obj.modified_date
{1/19/2010 12:20:50 PM}
    Date: {1/19/2010 12:00:00 AM}
    Day: 19
    DayOfWeek: Tuesday
    DayOfYear: 19
    Hour: 12
    Kind: Local
    Millisecond: 333
    Minute: 20
    Month: 1
    Second: 50
    Ticks: 633995004503331818
    TimeOfDay: {12:20:50.3331818}
    Year: 2010

Any idea what's going on? Even reading the fields from the database, then trying to save them back without changes, causes the error. Other classes have no problems, and I can't see any differences that would account for this error.

I've added

    <globalizati开发者_StackOverflowon culture="en-US" />

to my web.config, with no changes.

These problems are on my local dev

OK, here's what was happening. marc_s had the right idea.

There's was binder handling the updates:

  TryUpdateModel(editItem, new string[] { "LookupTable", "TextField1", "TextField2" });

I removed the "LookupTable" from the call to TryUpdateModel, and instead handle the value in the binder with:

  var fkid = Convert.ToInt32(controllerContext.HttpContext.Request.Form["LookupTable.ID"]);
  EntityKey ek = new EntityKey("entities.LookupTable", "ID", fkid);
  obj.LookupTableReference.EntityKey = ek;

Apparently, the EF was trying to update the LookupTable value for some reason.