Showing Different fields in EditorForModel vs. DisplayForModel modes in MVC2

Question

I have a viewmodel that has an int StateID field and a string StateName field like so:

public class DepartmentViewModel : BaseViewModel, IModelWithId
{
    // only show in edit mode
    public int StateId { get; set; }

    // only show in display mode
    public string StateName { get; set; }
}

I have a read only view that uses DisplayForModel and an update view that uses EditorForModel. I want the DisplayForModel view to show the StateName property, and the EditorForModel view use the StateID property (I am actually rendering a dropdownlist based on this).

I have not been able to figure out how to decorate my viewmodel properties to create this behavior.

Answer 1

A comment on CodeGrue's answer.

Make the attribute inherit IMetadataAware instead. That way you don't need to build your own DataAnnotationsModelMetadataProvider.

The new attribute would become something like:

[AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
public sealed class RenderModeAttribute : Attribute, IMetadataAware
{
    public RenderMode RenderMode { get; set; }

    public RenderModeAttribute(RenderMode renderMode)
    {
        RenderMode = renderMode;
    }

    public void OnMetadataCreated(ModelMetadata metadata)
    {
        switch (RenderMode)
        {
            case RenderMode.DisplayModeOnly:
                metadata.ShowForDisplay = true;
                metadata.ShowForEdit = false;
                break;

            case RenderMode.EditModeOnly:
                metadata.ShowForDisplay = false;
                metadata.ShowForEdit = true;
                break;

            case RenderMode.None:
                metadata.ShowForDisplay = false;
                metadata.ShowForEdit = false;
                break;
        }
    }
}

public enum RenderMode
{
    Any,
    EditModeOnly,
    DisplayModeOnly
}