C# toggle window by clicking NotifyIcon (taskbar i

问题:

My C# application consists of a taskbar icon (NotifyIcon) and an overhead window initially hidden. I want the user to be able to toggle the window visibility by clicking on the NotifyIcon (left, single click). Also the window is being hidden when loosing focus.

This is what I have so far, a subclassed System.Windows.Forms.Form:

Initialization:

this.ControlBox = false;
this.ShowIcon = false;
this.ShowInTaskbar = false;

// Instance variables: bool allowVisible;
//                     System.Windows.Forms.NotifyIcon notifyIcon;

this.allowVisible = false;
this.notifyIcon = new NotifyIcon();
this.notifyIcon.MouseUp += new MouseEventHandler(NotifyIconClicked);
this.Deactivate += new EventHandler(HideOnEvent);

Instance methods:

private void NotifyIconClicked(object sender, MouseEventArgs e)
{
    if (e.Button == System.Windows.Forms.MouseButtons.Left)
    {
        if (this.Visible)
            this.Hide();
        else
            this.Show();
    }
}

new public void Show()
{
    this.allowVisible = true;
    this.Visible = true;
    this.Activate();
}

new public void Hide()
{
    this.allowVisible = false;
    this.Visible = false;
}

private void HideOnEvent(object sender, EventArgs e)
{
    this.Hide();
}

protected override void SetVisibleCore(bool visible)
{
    base.SetVisibleCore(this.allowVisible ? visible : this.allowVisible);
}

Clicking the icon reveals the window like it should. But clicking it again hides it for as long as the mouse is being pressed, then resets it to visible.

My guess is that the mouse down event steals the focus from the window so it disappears. Then the mouse up event is triggered, showing the window as it is hidden.

My next idea was to read the window visibility at mouse down event, so I tested three events and logged the UNIX time as they are called:

notifyIcon.MouseDown
notifyIcon.MouseUp
this.LostFocus

The result is pretty weird: Let's say the window is visible. This happens when I click the icon: Focus lost is called immediately. Mouse down is called as soon as I release the mouse, right before the mouse up event.

1312372231 focus lost
1312372235 mouse down
1312372235 mouse up

Why is the mouse down event delayed?
How can I toggle the window?

回答1:

I think this may work for you.

I found an expert exchange post which contains a class which provides a method for checking whether the cursor is currently over the tray.

NotifyIcon - Detect MouseOut

Using this class I modified your HideOnEvent method like so:

    private void HideOnEvent(object sender, EventArgs e)
    {
        if (!WinAPI.GetTrayRectangle().Contains(Cursor.Position))
        {
            this.Hide();
        }
    }

Which seems to do what you need.

I have included the class below:

using System.Runtime.InteropServices;
using System.Drawing;

public class WinAPI
{
    public struct RECT
    {
        public int left;
        public int top;
        public int right;
        public int bottom;

        public override string ToString()
        {
            return "(" + left + ", " + top + ") --> (" + right + ", " + bottom + ")";
        }
    }

    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    public static extern IntPtr FindWindow(string strClassName, string strWindowName);

    [DllImport("user32.dll", SetLastError = true)]
    public static extern IntPtr FindWindowEx(IntPtr parentHandle, IntPtr childAfter, string className, IntPtr windowTitle);

    [DllImport("user32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    static extern bool GetWindowRect(IntPtr hWnd, out RECT lpRect);


    public static IntPtr GetTrayHandle()
    {
        IntPtr taskBarHandle = WinAPI.FindWindow("Shell_TrayWnd", null);
        if (!taskBarHandle.Equals(IntPtr.Zero))
        {
            return WinAPI.FindWindowEx(taskBarHandle, IntPtr.Zero, "TrayNotifyWnd", IntPtr.Zero);
        }
        return IntPtr.Zero;
    }

    public static Rectangle GetTrayRectangle()
    {
        WinAPI.RECT rect;
        WinAPI.GetWindowRect(WinAPI.GetTrayHandle(), out rect);
        return new Rectangle(new Point(rect.left, rect.top), new Size((rect.right - rect.left) + 1, (rect.bottom - rect.top) + 1));
    }
}

It is not a perfect solution but I hope this helps.