Queue

I thought I'd just see if I could get something to work using reflection.

In the following program, we start with an empty queue with a capacity of 16.

We then enqueue a couple of strings, call TrimToSize() and find that the capacity has now been reduced to 2:

using System;
using System.Collections;
using System.Reflection;

class Test
{
    static void Main()
    {
       Queue q = new Queue(16); 
       Type t = typeof(Queue); 
       BindingFlags bf = BindingFlags.Instance | BindingFlags.NonPublic;
       FieldInfo fi = t.GetField ("_array", bf);
       object[] oa = (object[])fi.GetValue(q);
       Console.WriteLine(oa.Length); // 16
       q.Enqueue("Hello");
       q.Enqueue("World");
       q.TrimToSize(); 
       oa = (object[])fi.GetValue(q);
       Console.WriteLine(oa.Length); // 2
       Console.ReadKey();
    }
} 

There's no way to do this from 'normal' code as the Queue class doesn't have a Capacity property.

You might be able to do it using reflection by obtaining the length of its private _array field which is an object[].

If you really need it, I could try to figure something out.