MVC - Rendering DropDownList of Enumerators

Introduction

We've all been there - how do I put enumerators into a drop down on a mvc web site? This is how I did it.

The Code

Given the following enumerator defintion:

public enum LocationType { Zipcode=0, City, County, State, Country, Address};

I created the following code. I started off with a base class, allowing me to continue with my chosen technique with additional enumerators:

public abstract class EnumListItem
{
    public string Key   { get; set; }
    public int    Value { get; set; }
}

And then inherited my item class from it:

public class LocTypeItem : EnumListItem
{
    public LocationType LocType 
    { 
        get { return Globals.IntToEnum(this.Value, LocationType.City) ; }
        set { this.Value = (int)value; }
    }
}

Next, I create a list class, and initialized it in the constructor:

public class LocationTypeList : List<LocTypeItem>
{
    public LocationTypeList()
    {
        this.Add(new LocTypeItem() { Key = "City",        LocType = LocationType.City    });
        this.Add(new LocTypeItem() { Key = "County",      LocType = LocationType.County  });
        this.Add(new LocTypeItem() { Key = "Country",     LocType = LocationType.Country });
        this.Add(new LocTypeItem() { Key = "State",       LocType = LocationType.State   });
        this.Add(new LocTypeItem() { Key = "Postal Code", LocType = LocationType.Zipcode });	
    }
}

And finally, I created a static Globals class with a property for the list so I could access it anytime I want, from anywhere I want:

public static partial class Globals
{
    public static LocationTypeList ListOfLocationTypes { get; set; }

    static Globals()
    {
        ListOfLocationTypes = new LocationTypeList();
    }
    
   // Used in the classes above to translate ints to the appropriate enum type
    public static T IntToEnum<T>(int value, T defaultValue)
	{
        T enumValue = (Enum.IsDefined(typeof(T), value)) ? (T)(object)value : defaultValue;
        return enumValue;
    }
}    

Using the code

In the view that renders the dropdownlist control, it looks like this:

@Html.DropDownListForEx(model => model.MyIntVar, new SelectList(ViewBag.LocationTypes,"Value","Key"))

Note - The DropDownListForEx method is an extension method that takes car of wrapping the dropdownlist in bootsrap styles and divs. As you can see it really de-clutters the code in your view. One of these days, I'll write an article about these extension methods (I have one for pretty much every standard control you'd see in a MVC app.

Points of Interest

I like to bury complexity as much as is reasonable, so the stuff I need to do all the time is easier.

History

22 Nov 2017 - Forgot to paste the Globals.IntToEnum method in the right place.

21 Nov 2017 - Forgot to include the Globals.IntToEnum method.

18 Nov 2017 - Inital post.