Can I send a SelectList through the UIHint Control Parameters? - asp.net-mvc

Question

Can I send a SelectList through a Data Annotation? Something like...
[UIHint("DropDownList", "", new SelectList(new[] {"one","two","three"}))]
public virtual int? OptionID { get; set; }
I don't understand the syntax but this seems possible. If so, how do I access it from an editor template?
If not, how could I dynamically send a SelectList to a DropDownList Editor Template? I specifically would like to avoid making a separate template for every SelectList - I have too many of them. Thanks
EDIT: I'm working on the second option (Reflection) because I thought it might be more direct than overriding that 15-syllable monster, the DataAnnotationsModelMetadataProvider.

Answer 1

You might want to take a look at this blog post:
http://mikevdm.com/BlogEntry/Key/Using-UIHint-With-ControlParameters-in-MVC
Here's a relevant quote:
ControlParameters are limited in that they can only accept (compile-time) constant values, in a somewhat unusual syntax, but they do allow simple vales (true/false, enumerated values, etc.), so your templated helper can behave slightly differently based on parameters. This allows you to combine related functionality, usually found in individual templates (with lots of code duplication), into one single template.
In my app, all my drop down lists were either nullable bools (Yes, No, not set) or enums. I took the route of making a separate template for each one, but using helper methods to make the code within each template very minimal.
For example, I have a template called Level (where Level is an enum):
The code is just a couple usings plus....
#Html.DropDownListFor(model => model, Model.ToSelectList<Level>())
I use these extension methods for ToSelectList:
public static SelectList ToSelectList<TEnum>(this TEnum? value) where TEnum : struct
{
var items = GetSelectListItems<TEnum>().ToList();
items.Insert(0, new SelectListItem { Value = "", Text = LabelIfNull });
return new SelectList(items, "Value", "Text", value.ToString());
}
public static SelectList ToSelectList<TEnum>(this TEnum value)
{
var items = GetSelectListItems<TEnum>();
return new SelectList(items, "Value", "Text", value.ToString());
}
public static IEnumerable<SelectListItem> GetSelectListItems<TEnum>()
{
var values = System.Enum.GetNames(typeof(TEnum));
return values.Select(v => new SelectListItem { Value = v, Text = v.ToFriendlyName() });
}
public static SelectList ToSelectList(this bool isTrue)
{
var items = new[]
{
new SelectListItem { Value = "true", Text = LabelIfTrue },
new SelectListItem { Value = "false", Text = LabelIfFalse }
};
return new SelectList(items, "Value", "Text", isTrue.ToString());
}
public static SelectList ToSelectList(this bool? isTrue)
{
var items = new[]
{
new SelectListItem { Value = string.Empty, Text = LabelIfNull },
new SelectListItem { Value = "true", Text = LabelIfTrue },
new SelectListItem { Value = "false", Text = LabelIfFalse }
};
return new SelectList(items, "Value", "Text", !isTrue.HasValue ? string.Empty : isTrue.Value.ToString());
}
Perhaps you could use control parameters to get down to a single template, but you'll definitely need to write your own DataAnnotationsModelMetadataProvider, as indicated in the blog post.