Question

TryParse family of methods uses out parameters; I could give Swap as an example of ref parameters being useful, but are there good examples in the .NET Base Class Library?

Answer 1

There are quite a few just in mscorlib. Run this to find them, and give it types in different assemblies to show others.

using System;
using System.Linq;

class Test
{    
    static void Main()
    {
        ShowRefsInAssemblyContaining(typeof(string));
    }

    static void ShowRefsInAssemblyContaining(Type exampleType)
    {
        var query = from type in exampleType.Assembly.GetTypes()
                    where type.IsPublic
                    from method in type.GetMethods()
                    where method.GetParameters()
                                .Any(p => p.ParameterType.IsByRef &&
                                         !p.IsOut)
                    select method;

        foreach (var method in query)
        {
            Console.WriteLine(method.DeclaringType + ": " + method);
        }
    }
}

Simplest example: Interlocked.CompareExchange.

(Don’t you love LINQ, btw?)