0

我会在标题中给出一些关于实际问题的指示,但我无法弄清楚它是什么。我只能说,在实现 appbar 时,表单在我尝试为变量赋值后不再响应,从而导致我不得不停止调试并重新启动机器以重新获得桌面工作区。错误的位置在下面的代码中注明,我只列出了错误点的代码。这里有什么我看不到的明显的东西吗?

static class Program
{
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new Form1());
    }
}

public partial class Form1 : AppBar
{
    public Form1() : base()
    {
        InitializeComponent();
    }

    //This is a button on the test form.
    //When clicked, the form should become a desktop application bar
    //docked to the top of the desktop.
    private void t_Click(object sender, EventArgs e)
    {
        base.SET_APPBAR();
    }
}

public class AppBar : Form
{
    protected internal Size appbarSize;
    protected internal Point appbarLocation;
    protected internal bool appbarMode;
    private EDGES appbarEdge;
    private RECT appbarRect;

    private uint ID { get; private set; }
    private IntPtr HANDLE { get; private set; }

    //constructor
    public AppBar() : base () //no issues here
    {
        appbarEdge = EDGES.ABE_TOP;
        appbarRect = new RECT();
        ID = 0;
        HANDLE = this.Handle;
        appbarMode = false;
    }

    protected internal void SET_APPBAR()
    {
        if (IS_NEW())
        {
            QUERY_AND_SET_POSITION(ref appbarRect); //Never get to here
        }
    }

    private bool IS_NEW()
    {
        if (appbarMode) //so far, so good
        {
            return false;
        }
        while (ID == 0) 
        {
            CREATE_ID(); //ID is created, I have verified this.
        }
        this.FormBorderStyle = FormBorderStyle.FixedToolWindow; //BorderStyle does change
        appbarSize = this.Size; //Size is correct
        appbarLocation = this.Location; //still no issues
        NEW(); //this is where the error begins (see code further down)
        return appbarMode; //Never get here
    }

    private void CREATE_ID()
    {
        ID = Hooks.RegisterWindowMessage(Guid.NewGuid().ToString());
    }

    private void QUERY_AND_SET_POSITION(ref RECT appbarRect)
    {
        SET_APPBAR_SIZE(ref appbarRect);
        QUERY_POS(ref appbarRect);
        APPBAR_RESIZE(ref appbarRect);
        SET_POS(ref appbarRect);
        this.Location = new Point(appbarRect.left, appbarRect.top);
        appbarSize = new Size(appbarRect.right - appbarRect.left, appbarRect.bottom - appbarRect.top);
        this.Size = appbarSize;
    }

    private void SET_APPBAR_SIZE(ref RECT appbarRect)
    {
        switch (appbarEdge)
        {
            case (EDGES.ABE_BOTTOM):
                appbarRect.left = 0;
                appbarRect.right = SystemInformation.PrimaryMonitorSize.Width;
                appbarRect.top = SystemInformation.PrimaryMonitorSize.Height - appbarSize.Height;
                appbarRect.bottom = SystemInformation.PrimaryMonitorSize.Height;
                break;
            case (EDGES.ABE_LEFT):
                appbarRect.left = 0;
                appbarRect.right = appbarSize.Width;
                appbarRect.top = 0;
                appbarRect.bottom = SystemInformation.PrimaryMonitorSize.Height;
                break;
            case (EDGES.ABE_RIGHT):
                appbarRect.left = SystemInformation.PrimaryMonitorSize.Width - appbarSize.Width;
                appbarRect.right = SystemInformation.PrimaryMonitorSize.Width;
                appbarRect.top = 0;
                appbarRect.bottom = SystemInformation.PrimaryMonitorSize.Height;
                break;
            default:
                appbarRect.left = 0;
                appbarRect.right = SystemInformation.PrimaryMonitorSize.Width;
                appbarRect.top = SystemInformation.WorkingArea.Top;
                appbarRect.bottom = appbarSize.Height;
                break;
        }
    }

    private void APPBAR_RESIZE(ref RECT appbarRect)
    {
        switch (appbarEdge)
        {
            case (EDGES.ABE_TOP):
                appbarRect.bottom = appbarRect.top + appbarSize.Height;
                break;
            case (EDGES.ABE_BOTTOM):
                appbarRect.top = appbarRect.bottom - appbarSize.Height;
                break;
            case (EDGES.ABE_LEFT):
                appbarRect.right = appbarRect.left + appbarSize.Width;
                break;
            case (EDGES.ABE_RIGHT):
                appbarRect.left = appbarRect.right - appbarSize.Width;
                break;
        }
    }

    private void APPBAR_CALLBACK(ref Message apiMessage)
    {
        switch ((NOTIFICATIONS)(uint)apiMessage.WParam)//? on int vs uint here
        {
            case (NOTIFICATIONS.ABN_STATECHANGE):
                STATE_CHANGE();
                break;
            case (NOTIFICATIONS.ABN_POSCHANGED):
                QUERY_AND_SET_POSITION(ref appbarRect);
                break;
            case (NOTIFICATIONS.ABN_FULLSCREENAPP):
                if ((int)apiMessage.LParam != 0)
                {
                    this.SendToBack();
                    this.TopMost = false;
                }
                else
                {
                    STATE_CHANGE();
                }
                break;
            case (NOTIFICATIONS.ABN_WINDOWARRANGE):
                //first call
                if ((int)apiMessage.LParam != 0)
                {
                    this.Visible = false;
                }
                //second call
                else
                {
                    this.Visible = true;
                }
                break;
        }
    }

    protected override void WndProc(ref Message apiMessage)
    {
        if (appbarMode)
        {
            if (HANDLE == apiMessage.HWnd)
            {
                APPBAR_CALLBACK(ref apiMessage);
            }
            else if (apiMessage.Msg == (int)API_MESSAGES.WM_ACTIVATE)
            {
                ACTIVATE();
            }
            else if (apiMessage.Msg == (int)API_MESSAGES.WM_WINDOWPOSCHANGED)
            {
                WINDOW_POS_CHANGED();
            }
        }
        base.WndProc(ref apiMessage);
    }

    private void NEW()
    {
        APPBARDATA data = new APPBARDATA(); //no apparent issue
        data.cbSize = (uint)Marshal.SizeOf(data); //no apparent issue
        data.hWnd = HANDLE; //no apparent issue
        data.uCallbackMessage = ID; //no apparent issue
        if (Hooks.SHAppBarMessage((uint)DWORD.ABM_NEW, ref data) != 0) //SHAppBar returns 1 (true)
        {
            //no issue if I were to place a MessageBox here
            appbarMode = true; // why in the world is this causing an issue?????
            //can't do anything from this point
        }
    }
}

public static class Hooks
{
    [DllImport("shell32.dll", EntryPoint = "SHAppBarMessage")]
    public static extern uint SHAppBarMessage(uint dwMessage, ref APPBARDATA pData);

    [DllImport("user32.dll", EntryPoint = "RegisterWindowMessage")]
    public static extern uint RegisterWindowMessage(
        [MarshalAs(UnmanagedType.LPTStr)]
        string lpString);
}

无论发生什么问题,我都无法单击任何按钮或关闭表单。桌面工作区总是适当调整大小。希望所有这些对某人有意义。感谢您提前查看。

4

1 回答 1

3

问题是您正在 UI 线程中执行长时间运行的操作。这会阻塞 UI 线程并阻止它执行任何其他操作(从绘制更改、响应按钮单击或鼠标移动事件等)。

您需要在后台线程中执行长时间运行的操作。虽然您可以手动执行此操作,BackgroundWorker但最好使用 a,因为它正是为这个应用程序设计的。它不仅会为您创建/配置后台线程,而且还提供简单易用的机制,用于在后台任务完成时更新 UI,在任务运行时更新 UI 进度等。

请注意,在后台线程中,您无法访问 UI 元素;它们需要从 UI 线程访问。您应该将所有从 UI 获取信息的代码移动到开始后台任务之前(将其保存在本地变量或字段中以供以后使用),并且您应该将所有代码移动到最后,以根据结果更新 UI,(在RunWorkerCompleted事件,如果使用BackgroundWorker)。DoWork除了for之外的所有事件BackgroundWorker都在 UI 线程中执行,因此可以访问您的 UI 控件。

于 2012-12-07T18:35:29.037 回答