Is this overusing extension methods?

Question

I'm looking to make certain functions as generic as possible.

In my MVC applications I have to convert a number of complex IEnumerable objects to SelectLists for dropdown display etc.

At first I created a static List class with conversion methods for each complex object. This amounted to a lot of code. I next started using linq statements to do the conversion:

var list = (from o in SessionTypes select new SelectListItem { Value = o.ID.ToString(), Text = o.Title }).ToList();

but again, this still was a lot of code when taken over many such conversions.

I finally settled something similar to:

public IEnumerable<SelectListItem> ToSelectList<T>(IEnumerable<T> enumerable, Func<T, string> value, Func<T, string> text)
    {
        return enumerable.Select(f => new SelectListItem()
        {
            Value = value(f),
            Text = text(f),
        });
    }

and to make it easier to use, I made it an extension method:

public static IEnumerable<SelectListItem> ToSelectList<T>(this IEnumerable<T> enumerable, Func<T, string> value, Func<T, string> text)
    {
        return enumerable.Select(f => new SelectListItem()
        {
            Value = value(f),
            Text = text(f),
        });
    }

So now, all I have to do is:

var list = SessionTypes.ToSelectList(o => o.ID.ToString(), o => o.Title) as List<SelectListItem>; 

I have similar methods such as .ToDictionary too.

Is this overusing Extension methods? I worry that I'm hiding too much code away in extension methods which might be distorting my models, would it be better to use linq conversions for transparency?

Answer 1

You can bind IDictionary<,> to the DropDownList DataSource directly, in WebForms you need to specify mappings like DataValueField="Key" and DataTextField="Value". Considering that why not just use LINQ ToDictionary() method?

dropDownList.DataValueField = "Key";
dropDownList.DataTextField = "Value";
dropDownList.DataSource = 
                SessionTypes.ToDictionary(k => k.ID.ToString(), 
                                          v => v.Title);