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using System;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Runtime.InteropServices;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Interop;
// ReSharper disable IdentifierTypo
// ReSharper disable InconsistentNaming
// ReSharper disable EnumUnderlyingTypeIsInt
// ReSharper disable MemberCanBePrivate.Local
// ReSharper disable UnusedMember.Local
// ReSharper disable UnusedMember.Global
namespace Walterlv.Demo.DesktopDocking
{
/// <summary>
/// 表示窗口停靠到桌面上时的边缘方向。
/// </summary>
public enum AppBarEdge
{
/// <summary>
/// 窗口停靠到桌面的左边。
/// </summary>
Left = 0,
/// <summary>
/// 窗口停靠到桌面的顶部。
/// </summary>
Top,
/// <summary>
/// 窗口停靠到桌面的右边。
/// </summary>
Right,
/// <summary>
/// 窗口停靠到桌面的底部。
/// </summary>
Bottom,
/// <summary>
/// 窗口不停靠到任何方向,而是成为一个普通窗口占用剩余的可用空间(工作区)。
/// </summary>
None
}
/// <summary>
/// 提供将窗口停靠到桌面某个方向的能力。
/// </summary>
public class DesktopAppBar
{
public static readonly DependencyProperty AppBarProperty = DependencyProperty.RegisterAttached(
"AppBar", typeof(AppBarEdge), typeof(DesktopAppBar),
new PropertyMetadata(AppBarEdge.None, OnAppBarEdgeChanged));
public static AppBarEdge GetAppBar(Window window) => (AppBarEdge) window.GetValue(AppBarProperty);
public static void SetAppBar(Window window, AppBarEdge value) => window.SetValue(AppBarProperty, value);
private static readonly DependencyProperty AppBarProcessorProperty = DependencyProperty.RegisterAttached(
"AppBarProcessor", typeof(AppBarWindowProcessor), typeof(DesktopAppBar), new PropertyMetadata(null));
[SuppressMessage("ReSharper", "ConditionIsAlwaysTrueOrFalse")]
private static void OnAppBarEdgeChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (DesignerProperties.GetIsInDesignMode(d))
{
return;
}
var oldValue = (AppBarEdge) e.OldValue;
var newValue = (AppBarEdge) e.NewValue;
var oldEnabled = oldValue is AppBarEdge.Left
|| oldValue is AppBarEdge.Top
|| oldValue is AppBarEdge.Right
|| oldValue is AppBarEdge.Bottom;
var newEnabled = newValue is AppBarEdge.Left
|| newValue is AppBarEdge.Top
|| newValue is AppBarEdge.Right
|| newValue is AppBarEdge.Bottom;
if (oldEnabled && !newEnabled)
{
var processor = (AppBarWindowProcessor) d.GetValue(AppBarProcessorProperty);
processor.Detach();
}
else if (!oldEnabled && newEnabled)
{
var processor = new AppBarWindowProcessor((Window) d);
d.SetValue(AppBarProcessorProperty, processor);
processor.Attach(newValue);
}
else if (oldEnabled && newEnabled)
{
var processor = (AppBarWindowProcessor) d.GetValue(AppBarProcessorProperty);
processor.Update(newValue);
}
}
/// <summary>
/// 包含对 <see cref="Window"/> 进行操作以便使其成为一个桌面停靠窗口的能力。
/// </summary>
private class AppBarWindowProcessor
{
/// <summary>
/// 创建 <see cref="AppBarWindowProcessor"/> 的新实例。
/// </summary>
/// <param name="window">需要成为停靠窗口的 <see cref="Window"/> 的实例。</param>
public AppBarWindowProcessor(Window window)
{
_window = window;
_callbackId = RegisterWindowMessage("AppBarMessage");
_hwndSourceTask = new TaskCompletionSource<HwndSource>();
var source = (HwndSource) PresentationSource.FromVisual(window);
if (source == null)
{
window.SourceInitialized += OnSourceInitialized;
}
else
{
_hwndSourceTask.SetResult(source);
}
_window.Closed += OnClosed;
}
private readonly Window _window;
private readonly TaskCompletionSource<HwndSource> _hwndSourceTask;
private readonly int _callbackId;
private WindowStyle _restoreStyle;
private Rect _restoreBounds;
private ResizeMode _restoreResizeMode;
private bool _restoreTopmost;
private AppBarEdge Edge { get; set; }
/// <summary>
/// 在可以获取到窗口句柄的时候,给窗口句柄设置值。
/// </summary>
private void OnSourceInitialized(object sender, EventArgs e)
{
_window.SourceInitialized -= OnSourceInitialized;
var source = (HwndSource) PresentationSource.FromVisual(_window);
_hwndSourceTask.SetResult(source);
}
/// <summary>
/// 在窗口关闭之后,需要恢复窗口设置过的停靠属性。
/// </summary>
private void OnClosed(object sender, EventArgs e)
{
_window.Closed -= OnClosed;
_window.ClearValue(AppBarProperty);
}
/// <summary>
/// 将窗口属性设置为停靠所需的属性。
/// </summary>
private void ForceWindowProperties()
{
_window.WindowStyle = WindowStyle.None;
_window.ResizeMode = ResizeMode.NoResize;
_window.Topmost = true;
}
/// <summary>
/// 备份窗口在成为停靠窗口之前的属性。
/// </summary>
private void BackupWindowProperties()
{
_restoreStyle = _window.WindowStyle;
_restoreBounds = _window.RestoreBounds;
_restoreResizeMode = _window.ResizeMode;
_restoreTopmost = _window.Topmost;
}
/// <summary>
/// 使一个窗口开始成为桌面停靠窗口,并开始处理窗口停靠消息。
/// </summary>
/// <param name="value">停靠方向。</param>
public async void Attach(AppBarEdge value)
{
var hwndSource = await _hwndSourceTask.Task;
BackupWindowProperties();
var data = new APPBARDATA();
data.cbSize = Marshal.SizeOf(data);
data.hWnd = hwndSource.Handle;
data.uCallbackMessage = _callbackId;
SHAppBarMessage((int) ABMsg.ABM_NEW, ref data);
hwndSource.AddHook(WndProc);
Update(value);
}
/// <summary>
/// 更新一个窗口的停靠方向。
/// </summary>
/// <param name="value">停靠方向。</param>
public async void Update(AppBarEdge value)
{
var hwndSource = await _hwndSourceTask.Task;
Edge = value;
var bounds = TransformToAppBar(hwndSource.Handle, _window.RestoreBounds, value);
ForceWindowProperties();
Resize(_window, bounds);
}
/// <summary>
/// 使一个窗口从桌面停靠窗口恢复成普通窗口。
/// </summary>
public async void Detach()
{
var hwndSource = await _hwndSourceTask.Task;
var data = new APPBARDATA();
data.cbSize = Marshal.SizeOf(data);
data.hWnd = hwndSource.Handle;
SHAppBarMessage((int) ABMsg.ABM_REMOVE, ref data);
_window.WindowStyle = _restoreStyle;
_window.ResizeMode = _restoreResizeMode;
_window.Topmost = _restoreTopmost;
Resize(_window, _restoreBounds);
}
private IntPtr WndProc(IntPtr hwnd, int msg,
IntPtr wParam, IntPtr lParam, ref bool handled)
{
if (msg == _callbackId)
{
if (wParam.ToInt32() == (int) ABNotify.ABN_POSCHANGED)
{
var hwndSource = _hwndSourceTask.Task.Result;
var bounds = TransformToAppBar(hwndSource.Handle, _window.RestoreBounds, Edge);
Resize(_window, bounds);
handled = true;
}
}
return IntPtr.Zero;
}
private static void Resize(Window window, Rect bounds)
{
window.Left = bounds.Left;
window.Top = bounds.Top;
window.Width = bounds.Width;
window.Height = bounds.Height;
}
private Rect TransformToAppBar(IntPtr hWnd, Rect area, AppBarEdge edge)
{
var data = new APPBARDATA();
data.cbSize = Marshal.SizeOf(data);
data.hWnd = hWnd;
data.uEdge = (int) edge;
if (data.uEdge == (int) AppBarEdge.Left || data.uEdge == (int) AppBarEdge.Right)
{
data.rc.top = 0;
data.rc.bottom = (int) SystemParameters.PrimaryScreenHeight;
if (data.uEdge == (int) AppBarEdge.Left)
{
data.rc.left = 0;
data.rc.right = (int) Math.Round(area.Width);
}
else
{
data.rc.right = (int) SystemParameters.PrimaryScreenWidth;
data.rc.left = data.rc.right - (int) Math.Round(area.Width);
}
}
else
{
data.rc.left = 0;
data.rc.right = (int) SystemParameters.PrimaryScreenWidth;
if (data.uEdge == (int) AppBarEdge.Top)
{
data.rc.top = 0;
data.rc.bottom = (int) Math.Round(area.Height);
}
else
{
data.rc.bottom = (int) SystemParameters.PrimaryScreenHeight;
data.rc.top = data.rc.bottom - (int) Math.Round(area.Height);
}
}
SHAppBarMessage((int) ABMsg.ABM_QUERYPOS, ref data);
SHAppBarMessage((int) ABMsg.ABM_SETPOS, ref data);
return new Rect(data.rc.left, data.rc.top,
data.rc.right - data.rc.left, data.rc.bottom - data.rc.top);
}
[StructLayout(LayoutKind.Sequential)]
private struct RECT
{
public int left;
public int top;
public int right;
public int bottom;
}
[StructLayout(LayoutKind.Sequential)]
private struct APPBARDATA
{
public int cbSize;
public IntPtr hWnd;
public int uCallbackMessage;
public int uEdge;
public RECT rc;
public readonly IntPtr lParam;
}
private enum ABMsg : int
{
ABM_NEW = 0,
ABM_REMOVE,
ABM_QUERYPOS,
ABM_SETPOS,
ABM_GETSTATE,
ABM_GETTASKBARPOS,
ABM_ACTIVATE,
ABM_GETAUTOHIDEBAR,
ABM_SETAUTOHIDEBAR,
ABM_WINDOWPOSCHANGED,
ABM_SETSTATE
}
private enum ABNotify : int
{
ABN_STATECHANGE = 0,
ABN_POSCHANGED,
ABN_FULLSCREENAPP,
ABN_WINDOWARRANGE
}
[DllImport("SHELL32", CallingConvention = CallingConvention.StdCall)]
private static extern uint SHAppBarMessage(int dwMessage, ref APPBARDATA pData);
[DllImport("User32.dll", CharSet = CharSet.Auto)]
private static extern int RegisterWindowMessage(string msg);
}
}
}
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