Question

I am creating an attribute that I will use to provide additional information about the unit of measure of a property in an MVC 3 ViewModel. This follows me asking about the best way to accomplish this.

I have created a UnitOfMeasure attribute that passes additional information to the string template via the AdditionalValues metadata. Ideally I would like to create a Editor Template for UnitOfMeasure rather than adding it to the string editor template.

Is there anyway to tell a custom metadata provider to change the selected template? Effectively if it sees the UnitOfMeasure attribute on a property then I would like to also add UiHint(“UnitOfMeasure”) automaticallly behind the scenes. That way I would not have to add code for my UnitOfMeasure helper in the string editor template.

I should note that I don’t want to use UiHint control parameters (unless it is the only option)

Thanks

Answer 1

You could have your custom attribute derive from UIHint:

public class UnitOfMeasureAttribute : UIHintAttribute, IMetadataAware
{
    public UnitOfMeasure(): base("foo")
    {

    }

    public void OnMetadataCreated(ModelMetadata metadata)
    {
        throw new NotImplementedException();
    }
}

and then:

public class MyViewModel
{
    [UnitOfMeasure]
    public string Foo { get; set; }
}

or:

public class MyViewModel
{
    public string Foo { get; set; }
}

and in both case in the view:

@Html.EditorFor(x => x.Foo)

in the first case, obviously the ~/Views/Shared/EditorTemplates/foo.cshtml custom template will be used whereas in the second the default string template.