BinarySearch(Object)方法使用默认比较获取元素的整个排序的ArrayList，并返回元素的索引，这意味着它在排序的ArrayList中搜索并给出找到元素的索引值。

C# ArrayList中的BinarySearch方法示例

namespace ConsoleApplication1
{

  class Program
  {
      static void Main(string[] args)
      {

          ArrayList numbers = new ArrayList();
          numbers.Add(10);
          numbers.Add(22);
          numbers.Add(3);

          numbers.Add(5);
          numbers.Add(9);
          Console.WriteLine("The elements of the arraylist are:");
          foreach (int i in numbers)

          {
              Console.WriteLine(i);
          }
          numbers.Sort();

          Console.WriteLine("After sorting the elements of the arraylist are:");
          foreach (int i in numbers)
          {
              Console.WriteLine(i);

          }
          Console.WriteLine("The element 22 searched at:" + numbers.BinarySearch(22));
          Console.WriteLine("The element 10 searched at:" + numbers.BinarySearch(10)); 
      }

  }
}