A generic convertor for IEnumerable<T>

Apart from ForEach<T>, as I described in my previous post, I noticed the absence of ConvertAll<T> on everything but List<T> as well. Pretty annoying when I wanted to convert a list of business objects of So I extended my static class GenericUtilities with another extension methdo

using System;
using System.Collections.Generic;

namespace LocalJoost.Utilities
{
  public static class GenericExtensions
  {
    // previous code for ForEach omitted.

    public static IEnumerable<TC> ConvertAll<T, TC>(
      this IEnumerable<T> inputList, 
      Converter<T, TC> convert)
    {
        foreach( var t in inputList )
        {
            yield return convert(t);
        }
  }
}

This permitted me to do something like this:

return ListRubriek.Get()
  .ConvertAll(p => new CascadingDropDownNameValue(
        p.Omschrijving, p.Id.ToString()))
  .ToArray();

to easily convert a list of CSLA business objects into a list that could be used in an ASP.NET Ajax Cascading dropdown. Nothing special for the veteran functional programmer I guess but still, useful.

This is actually the 2nd version - thanks to Jarno Peschier for some constructive criticism

One ForEach to rule them all

I ran into this when I was investigating functional programming in C#. That’s been around for a while, but apart from using it for traversing or modifying collections or lists, I never actually created something that was making use of a function parameter.

Anyway, one of my most used constructs is the ForEach<T> method of List<T>. I always thought it to be quite annoying that it is only available for List<T>. Not for IList<T>, ICollection<T>, or whatever. Using my trademark solution pattern – the extension method ;-)
I tried the following:

using System;
using System.Collections.Generic;

namespace LocalJoost.Utilities
{
  public static class GenericExtensions
  {
    public static void ForEach<T>(this IEnumerable<T> t, Action<T> action)
    {
      foreach (var item in t)
      {
        action(item);
      }
    }
  }
}

And that turned out to be all. IList<T>, ICollection<T>, everything that implements IEnumerable<T> – now sports a ForEach method. It even works for arrays, so if you have something like this

string[] arr = {"Hello", "World", "how", "about", "this"};
arr.ForEach(Console.WriteLine);

It nicely prints out

Hello
World
how
about
this

I guess it's a start. Maybe it is of some use to someone, as I plod on ;-)