More fluent C# / .NET

Question

A co-worker of mine came up with this and I wonder what others think? Personally, I find it interesting but wonder if it is too big a departure? Code examples below. Extension methods at the bottom.

General thoughts please. Other extension methods that could be added?

var ddl = Page.FindControl("LocationDropDownList") as DropDownList;

ddl.Visible = true;
ddl.SelectedValue = "123";

if(isAdmin)
    ddl  .SelectedValue = "111";

Becomes:

Page.FindControl("LocationDropDownList")
    .CastAs<DropDownList>()
    .With(d => d.Visible = true)
    .With(d => d.SelectedValue = "123")
    .WithIf(isAdmin, d => d.Items.Add(new ListItem("Admin", "1")));

Or:

 Page.FindControl("LocationDropDownList")
       .CastAs<DropDownList>()
       .With(d =>
       {
           d.Visible = true;
           d.SelectedValue = "123";
       })
       .WithIf(isAdmin, d => d.SelectedValue = "111");

Extension methods:

public static TResult CastAs<TResult>(this object obj) where TResult : class
{
    return obj as TResult;
}

public static T With<T>(this T t, Action<T> action)
{
    if (action == null)
        throw new ArgumentNullException("action");

    action(t);

    return t;
}

public static T WithIf<T>(this T t, bool condition, Action<T> action)
{
    if (action == null)
        throw new ArgumentNullException("action");

    if (condition)
        action(t);

    return t;
}

Answer 1

I say stick with the first version without the extension methods or lamba expressions. These are relatively new concepts so not many developers will have a handle on them yet outside their use in data retrieval/manipulation from a database. If you use them you may have a hit on maintenance cost. It is nice to say "read up if this is Greek to you"; but in real-life that may be the best approach.

Answer 2

That is some extension method abuse if I ever saw it!

Answer 3

One more vote for "not useful". The With extension method doesn't do anything except wrap up sequenced statements with a method. C# already already has a built-in function for sequencing statements, its called ;.

Similarly, the WithIf wraps an if-statement without any modification to the control flow. From my point of view, you're only inviting yourself to methods like:

public static T For<T>(
    this T t, int start, Func<int, bool> cond, Action<T, int> f)
{
    for(int i = start; cond(i); i++)
    {
        f(t, i);
    }
    return t;
}

Answer 4

I see no advantage to this besides being confusing to the reader. With respect to my fellow answerer, I would like to know on what planet this is more readable. As far as I can tell, the first version has more or less perfect readability, whereas this is fairly readable, but makes the reader wonder whether there's some strange magic happening within With and WithIf.

Compared to the first version, it's longer, harder to type, less obvious, and less performant.

Answer 5

I'd say stick with the first version. What you've posted is too clever to be immediately useful to someone reading the code.

You could even go a step further and do away with that "var":

DropDownList ddl = (DropDownList) Page.FindControl("ddlName");

Answer 6

I predict the whole "fluent interface" fad will be the "hungarian notation" of the 2000's. I personally think it doesn't look very clean and it runs the risk of becoming very inconsistent if you have multiple developers each with their own preference.