前几天的方案都比较复杂一些，再来一个简单的：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using MAPI;

namespace ConsoleApplication3
{
    class Program
    {
        [STAThread]
        static void Main()
        {
            Session session = new Session();
            session.Logon(null, null, false, true, 0, true, "exchange2007\nuser1");
            InfoStores infoStores = (InfoStores)session.InfoStores;
            for (int i = 0; i < (int)infoStores.Count; i++)
            {
                InfoStore infoStore = (InfoStore)infoStores.get_Item(i + 1);
                if (((string)infoStore.Name).IndexOf("Mailbox – ") >-1)
                {
                    Fields fields = (Fields)infoStore.Fields;
                    Field size = (Field)fields.get_Item(CdoPropTags.CdoPR_MESSAGE_SIZE, System.Reflection.Missing.Value);
                    Field count = (Field)fields.get_Item(CdoPropTags.CdoPR_CONTENT_COUNT, System.Reflection.Missing.Value);
                    Console.WriteLine(infoStore.Name + ": " + size.Value + "Bytes, messages:" + count.Value);
                }
            }
            session.Logoff();
            Console.ReadLine();
        }
    }
}

这个方案的问题是需要安装CDO，好在这个东东是微软的，而且很小，安装包才几百K，其实就是把MAPI的一些API包装成COM了，所以.net平台的那些语言都可以调。