Using a single view for derived mvc models

Question

I have a base model class, NotificationBase, and two derived models, GeneralNotification and ReleaseNotification.

public class NotificationBase
{
        public int Id { get; set; }

        [Required]
    [StringLength(50, ErrorMessage="Title must not exceed 50 characters.")]
    public string Title { get; set; }

    [Required(ErrorMessage="Type is required.")]
    public int TypeId { get; set; }

    [Required(ErrorMessage="Importance is required.")]
    public int ImportanceId { get; set; }

    public DateTime Created {get; set; }

    [Required(ErrorMessage="Start date is required.")]        
    public DateTime StartDate { get; set; }

    [Required(ErrorMessage="End date is required")]
    public DateTime EndDate { get; set; }

    [AllowHtml]
    [Required(ErrorMessage="Details are required")]
    public string Details { get; set; }                

}

public class GeneralNotification : NotificationBase
{
    [Required(ErrorMessage="Message is required.")]
    [StringLength(50, ErrorMessage = "Message must be maximum 50 chararacters long.")]
    public string Message { get; set; } 
}

  public class ReleaseNotification : NotificationBase
{
    [Required(ErrorMessage="Version is required.")]
    public string Version { get; set; }
}

I'm trying to use a single edit view to edit both derived notification types.

This view has a model of type NotificationBase.

The problem is I can't get the added properties of the derived types to be displayed in the edit view. Sending a model of the base type means I lose along the way the extra properties of the derived types.

Is there a workaround, or I just have to make separate views for each derived model ?

Answer 1

You can add a couple of conditions to your view. Suppose your view is strongly typed with base class:

@model NotificationBase

You can check for each subclass and add corresponding fields (untested code below!):

@if (Model is GeneralNotification)
{
    Html.TextBoxFor(m => ((GeneralNotification) m).Message);
}

The same goes for second subtype of course:

@if (Model is ReleaseNotification)
{
    Html.TextBoxFor(m => ((ReleaseNotification) m).Version);
}