Is there a good resource out there that explains the concept of enumerators and custom enumerators? Particularly one with a good solid example of why you would want to implement IEnumerable yourself and how you would use it effectively?
I occasionally come across yield and I am trying to get a better understanding of it.
The easiest example:
IEnumerable<string> GetNames()
{
yield return "Bob";
yield return "Bob's uncle";
yield return "Alice";
yield return "Stacy";
yield return "Stacy's mom";
}
Usage:
foreach (var name in GetNames())
{
Console.WriteLine(name);
}
To see it in action, place a debugger breakpoint on every line in the GetNames method.
The best example and reference I found is actually in the C# in Depth book from the almighty Jon Skeet. It's not too costly and it's worth it for everything you'll learn about C#.
Hi,
Another book I found quite useful when I was learning about IEnumerable and IEnumerator is Troelsen's Pro C# 2008 book. It explains what the interfaces contain and how to build iterators with the "yield" keyword.
Hope this help.
Here are a couple more resources for after you've gotten the basics down.
Wes has a great article on the performance characteristics of iterators:
http://blogs.msdn.com/wesdyer/archive/2007/03/23/all-about-iterators.aspx
If you have questions about why there are so many weird restrictions on what you can do in an iterator block, here's my seven part series on what motivated the unusual rules:
http://blogs.msdn.com/ericlippert/archive/tags/Iterators/default.aspx