Here’s a quick little tidbit that helped me this week. While writing a C# Windows application I found myself with a List of objects that did not implement a comparator interface. Because of this when I tried to call mylist.Sort() I got an error complaining about how it couldn’t compare the two objects.

The quick and dirty way to address this is C# .NET 3.5 and above is to use a Lambda expression. So given a list named mylist, here is how one can do this.

:::c#
mylist.Sort( (a, b) => a.ToString().CompareTo(b.ToString()) );

Notice how we start immediately with a set of arguments, followed by =>. This is the start of the lambda expression, and it tells us “arguments a and b goes to {some expression}”. In our case {some expression} is to take the string version of object a and compare it to the string version of object b. This works because the objects in question did override the ToString() method allowing us to do a basic string comparison between the two objects.

Pretty nifty eh? Happy coding!