The gist of the solution I pointed to in my comment is that you can use a specialized model for the view which contains a string representation instead of the DateTime type, which allows you to easily validate the value with RegularExpressionAttribute. When you receive this model on the server (as posted from the client), simply convert it to a corresponding database model.
public class ViewModel
{
[Required]
[RegularExpression("\d{2}-\d{2}-\d{4}\s\d{2}:\d{2}:\d{2}")]
public string MyDateTime { get; set; }
public Model ToPoco()
{
return new Model {
MyDateTime = DateTime.Parse(this.MyDateTime, "MM-dd-yyyy H:mm:ss")
};
}
}
public class Model
{
DateTime MyDateTime { get; set; }
}