The conversion of a datetime2 data type to a datetime data type resulted in an out-of-range value

The issue is that you're using ApplyPropertyChanges with a model object that has only been populated with data in the form (headline, story, and image). ApplyPropertyChanges applies changes to all properties of the object, including your uninitialized DateTime, which is set to 0001-01-01, which is outside of the range of SQL Server's DATETIME.

Rather than using ApplyPropertyChanges, I'd suggest retrieving the object being modified, change the specific fields your form edits, then saving the object with those modifications; that way, only changed fields are modified. Alternately, you can place hidden inputs in your page with the other fields populated, but that wouldn't be very friendly with concurrent edits.

Update:

Here's an untested sample of just updating some fields of your object (this is assuming you're using LINQ to SQL):

var story = _db.ArticleSet.First(a => a.storyId == ArticleToEdit.storyId);
story.headline = ArticleToEdit.headline;
story.story = ArticleToEdit.story;
story.image = ArticleToEdit.image;
story.modifiedDate = DateTime.Now;
_db.SubmitChanges();

This is a common error people face when using Entity Framework. This occurs when the entity associated with the table being saved has a mandatory datetime field and you do not set it with some value.

The default datetime object is created with a value of 01/01/1000 and will be used in place of null. This will be sent to the datetime column which can hold date values from 1753-01-01 00:00:00 onwards, but not before, leading to the out-of-range exception.

This error can be resolved by either modifying the database field to accept null or by initializing the field with a value.

DATETIME supports 1753/1/1 to "eternity" (9999/12/31), while DATETIME2 support 0001/1/1 through eternity.

Msdn

Answer: I suppose you try to save DateTime with '0001/1/1' value. Just set breakpoint and debug it, if so then replace DateTime with null or set normal date.