Web 浏览器控制自动化 C# 控制台应用程序测试中的内存泄漏

以下（在这篇文章的附言中）测试代码导致内存泄漏。您能否建议如何解决此内存泄漏问题？仅供参考：我使用的是VS2010 Prof，.NET Framework 4.0，Win7 Ultimate和IE9。可以使用 C# 代码行激活测试代码：

(new WebBrowser_STA_Test()).Main();

谢谢。

P.S. Web浏览器控制自动化C#控制台应用程序测试代码：

using System;
using System.Windows.Forms;
using System.Threading;
using NUnit.Framework;
using System.ComponentModel;
using System.Runtime.InteropServices;
namespace R_and_D_TestConsole
{
    public class WebBrowserThread : IDisposable 
    {
        private Action<string> _logger;
        public WebBrowserThread(Action<string> logger)
        {
            _logger = logger;
        }
        private void log(string message)
        {
            if (_logger != null) _logger(message);
        }
        private Thread _STA_Thread;
        public bool IsAlive
        {
            get
            {
                return (
                    _STA_Thread != null && 
                    _STA_Thread.IsAlive &&
                    !this.ThreadStoppingInProgress &&
                    !this.ThreadStopped
                    ); 
            }
        }
        public void Start()
        {
            log("Starting WebBrowser Thread...");
            _STA_Thread = new Thread(startBrowser);
            _STA_Thread.Name = "WebBrowser STA Thread";
            _STA_Thread.SetApartmentState(ApartmentState.STA);
            _STA_Thread.Start();
        }
        public WebBrowserHandler WebBrowserHandler { get; private set; }
        private void startBrowser()
        {
            log("WebBrowser Thread started.");
            WebBrowserHandler = new WebBrowserHandler(_logger);
            WebBrowserHandler.CreateBrowserInstance();
            Application.Run();
        }
        public bool ThreadStoppingInProgress { get; private set; }
        public bool ThreadStopped { get; private set; }
        public void Stop()
        {
            if (ThreadStoppingInProgress) return;
            try
            {
                ThreadStoppingInProgress = true;
                log("Stopping WebBrowser Thread...");
                log("Disposing WebBrowser Handler...");
                WebBrowserHandler.DisposeBrowserInstance();
                log("WebBrowser Handler partially disposed.");
                _STA_Thread.Abort();
                Application.ExitThread();
                log("WebBrowser Thread stopped.");
            }
            finally
            {
                ThreadStopped = true;
                ThreadStoppingInProgress = false;
            }
        }
        public bool Disposed { get; private set; }
        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }
        protected virtual void Dispose(bool disposing)
        {
            if (!this.Disposed)
            {
                if (disposing)
                {
                    if (WebBrowserHandler != null)
                    {
                        WebBrowserHandler.Dispose();
                        WebBrowserHandler = null;
                        log("WebBrowser Handler object instance and its child objects disposed completely (?)");
                    }
                    _logger = null;
                    _STA_Thread = null;
                }
                this.Disposed = true;
            }
        }
    }
    public class WebBrowserHandlerBase : IDisposable
    {
        protected ISynchronizeInvoke _invokeHelper;
        protected WebBrowser _webBrowser;
        private Action<string> _logger;
        public WebBrowserHandlerBase(Action<string> logger)
        {
            _logger = logger;
        }
        protected void log(string message)
        {
            if (_logger != null) _logger(message);
        }
        public bool Activated { get; private set; }
        public void CreateBrowserInstance()
        {
            _webBrowser = new WebBrowser();
            _webBrowser.Visible = true;
            _webBrowser.DocumentCompleted += webBrowser_DocumentCompleted;
            _webBrowser.ScriptErrorsSuppressed = true;
            _invokeHelper = _webBrowser as ISynchronizeInvoke;
            this.Activated = true;
        }
        public void DisposeBrowserInstance()
        {
            if (!this.Activated) return;
            Action dispose = () =>
                {
                    log("WebBrowserHandler.DisposeBrowserInstance (1)");
                    _webBrowser.DocumentCompleted -= webBrowser_DocumentCompleted;
                    // the following line results in floating runtime errors - commented...
                    //_webBrowser.Dispose();  
                    log("WebBrowserHandler.DisposeBrowserInstance (2)");
                };
            if (_invokeHelper.InvokeRequired)
            {
                IAsyncResult result = _invokeHelper.BeginInvoke(dispose, null);
                _invokeHelper.EndInvoke(result);
            }
            else dispose(); 
            this.Activated = false;
        }
        public bool Disposed { get; private set; }
        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }
        protected virtual void Dispose(bool disposing)
        {
            if (!this.Disposed)
            {
                if (disposing)
                {
                    if (_webBrowser != null)
                    {
                        // The following line results in runtime error:
                        //   'COM object that has been separated from its underlying RCW cannot be used.'
                        //_webBrowser.Dispose();
                        log("Releasing WebBrowser ActiveX instance...");
                        if (_webBrowser.ActiveXInstance != null) Marshal.ReleaseComObject(_webBrowser.ActiveXInstance);
                        _webBrowser = null;
                    }
                    _logger = null;
                }
                this.Disposed = true;
            }
        }
        public bool NavigationCompleted { get; protected set; }
        public virtual void Navigate_Async(string url) { }
        public virtual void webBrowser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e) {}
    }
    public class WebBrowserHandler : WebBrowserHandlerBase 
    {
        public WebBrowserHandler(Action<string> logger):base(logger) {}
        public override void Navigate_Async(string url)
        {
            if (!this.Activated) throw new ApplicationException(string.Format("{0} is not yet activated.", this.GetType().Name) ) ; 
            Action<string> navigate = (x) =>
                {
                    NavigationCompleted = false;
                    _webBrowser.Navigate(x); 
                };
            if (_webBrowser.InvokeRequired) _webBrowser.Invoke(navigate, new object[] { url } ); 
            else navigate(url);
        }
        public override void webBrowser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            log(string.Format(" *** webBrowser_DocumentCompleted: {0} {1}", _webBrowser.ReadyState,  e.Url));
            if (NavigationCompleted) return;
            NavigationCompleted = _webBrowser.ReadyState == WebBrowserReadyState.Complete;
            if (NavigationCompleted)
            {
                log(string.Format(" *** {0} '{1}'", _webBrowser.DocumentText.Length, _webBrowser.DocumentTitle));       
            }
        }
    }
    public class WebBrowser_STA_Test
    {
        private void log(string message)
        {
            System.Console.WriteLine("[{0}] - {1}", System.Threading.Thread.CurrentThread.ManagedThreadId, message);   
        }
        public void Main()
        {
            for (int i =1; i <= 10; i++)
            {
                test();
                GC.Collect(); 
            }
        }
        private void test()
        {
            log("Test started.");
            foreach (string url in new string[] 
                   { 
                   "http://www.google.com", 
                   "http://www.bing.com", 
                   "http://www.yandex.ru" 
                   })
            {
                log(string.Format("+++ TEST URL = '{0}' +++", url));
                bool navigateMethodCalled = false;
                using (WebBrowserThread _wbTest = new WebBrowserThread(log))
                {
                    _wbTest.Start();
                    Application.DoEvents();
                    while (_wbTest.IsAlive)
                    {
                        if (_wbTest.IsAlive &&
                            _wbTest.WebBrowserHandler != null &&
                            _wbTest.WebBrowserHandler.Activated &&
                            !navigateMethodCalled) 
                        { navigateMethodCalled = true; _wbTest.WebBrowserHandler.Navigate_Async(url); }
                        if (_wbTest.IsAlive &&
                            _wbTest.WebBrowserHandler != null &&
                            _wbTest.WebBrowserHandler.NavigationCompleted) _wbTest.Stop();
                        Thread.Sleep(500);
                    }
                }
                log(string.Format("--- TEST URL = '{0}' ---'n", url));
            }
            log("Test finished.");
        }
    }
}