在XP Pro上使用WebBrowser控件绘制ToolStripComboBox访问冲突

Question

我正在调试一个问题，在Windows XP上，当用户锁定/解锁机器时，或者当用户按下.NET -alt-delete然后按下退出时，WPF4.0 (WinForm，而不是WPF4.0)应用程序崩溃(在这种情况下，不一定是锁定--但他们可以选择锁定、调出任务管理器等)。这是非常可重现的。

它与绘制ToolStripComboBox相关。这是在幕后的一些gdiplus例程中生成AccessViolationException。

我见过它崩溃的几种不同方式，但都是在绘制这个控件的相同区域。下面是一个堆栈跟踪：

System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
at System.Drawing.SafeNativeMethods.Gdip.GdipFillRectangleI(HandleRef graphics, HandleRef brush, Int32 x, Int32 y, Int32 width, Int32 height)
at System.Drawing.Graphics.FillRectangle(Brush brush, Int32 x, Int32 y, Int32 width, Int32 height)
at System.Drawing.Graphics.FillRectangle(Brush brush, Rectangle rect)
at System.Windows.Forms.ToolStripComboBox.ToolStripComboBoxControl.ToolStripComboBoxFlatComboAdapter.DrawFlatComboDropDown(ComboBox comboBox, Graphics g, Rectangle dropDownRect)
at System.Windows.Forms.ComboBox.FlatComboAdapter.DrawFlatCombo(ComboBox comboBox, Graphics g)
at System.Windows.Forms.ComboBox.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
...

有没有人有关于如何解决这个问题的建议，或者机器锁定/解锁或ctrl-alt-delete屏幕的意义是什么？

编辑：

我把它归结为一个粘贴在下面的简单应用程序，它在XP Pro上非常容易重现。这是非常简单的--几乎是我们所能得到的最简单的。一切都是在UI线程上创建/操作的。

namespace Test
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }
    }

    public class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, System.EventArgs e)
        {
            webBrowser2.Navigate("http://www.cnn.com");
        }

        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.toolStripContainer1 = new System.Windows.Forms.ToolStripContainer();
            this.webBrowser2 = new System.Windows.Forms.WebBrowser();
            this.toolStrip1 = new System.Windows.Forms.ToolStrip();
            this.toolStripLabel1 = new System.Windows.Forms.ToolStripLabel();
            this.toolStripComboBox1 = new System.Windows.Forms.ToolStripComboBox();
            this.toolStripContainer1.ContentPanel.SuspendLayout();
            this.toolStripContainer1.TopToolStripPanel.SuspendLayout();
            this.toolStripContainer1.SuspendLayout();
            this.toolStrip1.SuspendLayout();
            this.SuspendLayout();
            // 
            // toolStripContainer1
            // 
            this.toolStripContainer1.BottomToolStripPanelVisible = false;
            // 
            // toolStripContainer1.ContentPanel
            // 
            this.toolStripContainer1.ContentPanel.Controls.Add(this.webBrowser2);
            this.toolStripContainer1.ContentPanel.Size = new System.Drawing.Size(555, 268);
            this.toolStripContainer1.Dock = System.Windows.Forms.DockStyle.Fill;
            this.toolStripContainer1.LeftToolStripPanelVisible = false;
            this.toolStripContainer1.Location = new System.Drawing.Point(0, 0);
            this.toolStripContainer1.Name = "toolStripContainer1";
            this.toolStripContainer1.RightToolStripPanelVisible = false;
            this.toolStripContainer1.Size = new System.Drawing.Size(555, 296);
            this.toolStripContainer1.TabIndex = 1;
            this.toolStripContainer1.Text = "toolStripContainer1";
            // 
            // toolStripContainer1.TopToolStripPanel
            // 
            this.toolStripContainer1.TopToolStripPanel.Controls.Add(this.toolStrip1);
            // 
            // webBrowser2
            // 
            this.webBrowser2.Dock = System.Windows.Forms.DockStyle.Fill;
            this.webBrowser2.Location = new System.Drawing.Point(0, 0);
            this.webBrowser2.MinimumSize = new System.Drawing.Size(20, 20);
            this.webBrowser2.Name = "webBrowser2";
            this.webBrowser2.Size = new System.Drawing.Size(555, 268);
            this.webBrowser2.TabIndex = 0;
            // 
            // toolStrip1
            // 
            this.toolStrip1.Dock = System.Windows.Forms.DockStyle.None;
            this.toolStrip1.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.toolStripLabel1,
            this.toolStripComboBox1});
            this.toolStrip1.Location = new System.Drawing.Point(3, 0);
            this.toolStrip1.Name = "toolStrip1";
            this.toolStrip1.Size = new System.Drawing.Size(173, 28);
            this.toolStrip1.TabIndex = 0;
            // 
            // toolStripLabel1
            // 
            this.toolStripLabel1.Name = "toolStripLabel1";
            this.toolStripLabel1.Size = new System.Drawing.Size(38, 25);
            this.toolStripLabel1.Text = "blah";
            // 
            // toolStripComboBox1
            // 
            this.toolStripComboBox1.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;
            this.toolStripComboBox1.Items.AddRange(new object[] {
            "a b",
            "c",
            "d",
            "e",
            "f"});
            this.toolStripComboBox1.Name = "toolStripComboBox1";
            this.toolStripComboBox1.Size = new System.Drawing.Size(121, 28);
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(8F, 16F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(555, 296);
            this.Controls.Add(this.toolStripContainer1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.Load += new System.EventHandler(this.Form1_Load);
            this.toolStripContainer1.ContentPanel.ResumeLayout(false);
            this.toolStripContainer1.TopToolStripPanel.ResumeLayout(false);
            this.toolStripContainer1.TopToolStripPanel.PerformLayout();
            this.toolStripContainer1.ResumeLayout(false);
            this.toolStripContainer1.PerformLayout();
            this.toolStrip1.ResumeLayout(false);
            this.toolStrip1.PerformLayout();
            this.ResumeLayout(false);
        }
        #endregion

        private ToolStripContainer toolStripContainer1;
        private ToolStrip toolStrip1;
        private ToolStripLabel toolStripLabel1;
        private ToolStripComboBox toolStripComboBox1;
        private WebBrowser webBrowser2;
    }
}

编辑2：

到目前为止，我无法在Windows XP Media Center版本上重现这段视频，只能在XP Pro上重现。

Answer 1

我们遇到这个问题已经有一段时间了。相同的调用堆栈，当用户执行ctrl-alt-del并换行时会发生这种情况。场景有点不同，因为它发生在我们的WinForm应用程序中，它是WinForm和WPF控件的混合。在应用程序中，我们有一个驻留在ElementHost中的WPF UserControl，当此组件位于浮动窗口中时，将鼠标悬停在正在重新绘制的WinForm控件上，屏幕被锁定和解锁，AccessViolationException被引发，应用程序崩溃。值得一提的是，我们也在使用UltraDockWorkspace。

我们还没有找到解决方案，但最近在使用MS源代码进行调试时，我在抛出异常的方法中注意到了以下注释(在System.Drawing中的Graphics.cs中)：

         /// <devdoc>
    ///     GDI+ will return a 'generic error' with specific win32 last error codes when
    ///     a terminal server session has been closed, minimized, etc...  We don't want 
    ///     to throw when this happens, so we'll guard against this by looking at the
    ///     'last win32 error code' and checking to see if it is either 1) access denied 
    ///     or 2) proc not found and then ignore it. 
    ///
    ///     The problem is that when you lock the machine, the secure desktop is enabled and 
    ///     rendering fails which is expected (since the app doesn't have permission to draw
    ///     on the secure desktop). Not sure if there's anything you can do, short of catching
    ///     the desktop switch message and absorbing all the exceptions that get thrown while
    ///     it's the secure desktop. 
    /// </devdoc>
    private void CheckErrorStatus(int status) { 
        if (status != SafeNativeMethods.Gdip.Ok) { 
            // Generic error from GDI+ can be GenericError or Win32Error.
            if (status == SafeNativeMethods.Gdip.GenericError || status == SafeNativeMethods.Gdip.Win32Error) { 
                int error = Marshal.GetLastWin32Error();
                if (error == SafeNativeMethods.ERROR_ACCESS_DENIED || error == SafeNativeMethods.ERROR_PROC_NOT_FOUND ||
                        //here, we'll check to see if we are in a term. session...
                        (((UnsafeNativeMethods.GetSystemMetrics(NativeMethods.SM_REMOTESESSION) & 0x00000001) != 0) && (error == 0))) { 
                        return;
                    } 
                } 

            //legitimate error, throw our status exception 
            throw SafeNativeMethods.Gdip.StatusException(status);
        }
    }

根据我在这里的理解，由于在安全桌面模式下的渲染，AccessViolationException应该在这里被抑制，但在某些情况下，这个异常会被传播。

很抱歉，我不能提供解决方案，但希望这些信息是有用的。