Question

当我执行以下操作时（实际上我用不同的网页重复相同的整个代码）：

        Navigator nav;
        nav = new Navigator();
        nav.Browser.Navigate("http://www.amazon.com/gp/search/ref=sr_adv_b/?search-alias=stripbooks&unfiltered=1&field-keywords=&field-author=&field-title=&field-isbn=0471848573+&field-publisher=&node=&field-p_n_condition-type=&field-feature_browse-bin=&field-binding_browse-bin=&field-subject=&field-language=&field-dateop=&field-datemod=&field-dateyear=&sort=relevanceexprank&Adv-Srch-Books-Submit.x=18&Adv-Srch-Books-Submit.y=4");
        while (nav.Browser.ReadyState != WebBrowserReadyState.Complete) Application.DoEvents();
        nav.Dispose();

Navigator是一个包含公共WebBrowser的Form，就是这样。你可以自己测试一下，我认为会发生同样的情况，但每次都不会发生。您可能需要将其置于循环中并重复几次以解决问题。

Answer 1

使您的导航器表单如下所示：

public partial class Navigator : Form {
    private bool done;

    public Navigator() {
        InitializeComponent();
        Browser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(Browser_DocumentCompleted);
    }
    void Browser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e) {
        if (e.Url == Browser.Url) done = true;
    }
    public bool Completed {
        get { return done; }
    }
}

你的循环就像这样：

        Navigator nav;
        nav = new Navigator();
        nav.Browser.Navigate("http://www.amazon.com/gp/search/ref=sr_adv_b/?search-alias=stripbooks&unfiltered=1&field-keywords=&field-author=&field-title=&field-isbn=0471848573+&field-publisher=&node=&field-p_n_condition-type=&field-feature_browse-bin=&field-binding_browse-bin=&field-subject=&field-language=&field-dateop=&field-datemod=&field-dateyear=&sort=relevanceexprank&Adv-Srch-Books-Submit.x=18&Adv-Srch-Books-Submit.y=4"); //        http://msn.com"); //stackoverflow.com/questions/3661536/while-true-application-doevents-doesnt-know-when-the-program-finishes");
        this.Enabled = false;
        while (!nav.Completed) Application.DoEvents();
        this.Enabled = true;
        nav.Dispose();

Answer 2

当我尝试在ThreadPool排队执行中调用WebBrowser的Dispose（）函数时遇到了同样的问题。

我在Control.Invoke的委托中启动了一个Timer来解决它。这是我的代码：

    public delegate void SucceedDelegate();
    // calling by ThreadPool.QueueUserWorkItem(succeed);
    protected void succeed(Object obj){
        Application.OpenForms[0].Invoke(new SucceedDelegate(succeed0));
    }
    private void succeed0()
    {
        Timer timer = new Timer();
        timer.Interval = 1;
        timer.Tick += succeedHandler;
        timer.Start();
    }
    private void succeedHandler(object sender, EventArgs e)
    {
        ((Timer)sender).Stop();
        succeed00();
    }
    private void succeed00()
    {
        //call WebBrowser.Dispose() here
    }

这很难看，但运作良好。

Answer 3

尝试在循环之后添加另一个DoEvents，就在nav.Dispose（）

之前

            Navigator nav;
            nav = new Navigator();
            nav.Browser.Navigate("http://www.amazon.com/gp/search/ref=sr_adv_b/?search-alias=stripbooks&unfiltered=1&field-keywords=&field-author=&field-title=&field-isbn=0471848573+&field-publisher=&node=&field-p_n_condition-type=&field-feature_browse-bin=&field-binding_browse-bin=&field-subject=&field-language=&field-dateop=&field-datemod=&field-dateyear=&sort=relevanceexprank&Adv-Srch-Books-Submit.x=18&Adv-Srch-Books-Submit.y=4");
            while (nav.Browser.ReadyState != WebBrowserReadyState.Complete) Application.DoEvents();
            Application.DoEvents(); // will avoid launching of IE
            nav.Dispose();

为什么WebBrowser.Dispose（）有时会启动Internet Explorer？

3 个答案: