var dialog = new OpenFileDialog();
dialog.Filter = "图片|*.png;*.jpg|文本|*.txt|walterlv 的自定义格式|*.lvyi";
dialog.ShowDialog(this);

using System;
using System.Linq;
using System.Runtime.CompilerServices;

namespace Walterlv.Demo
{
    class Program
    {
        static void Main(string[] args)
        {
            var table = new ConditionalWeakTable<string, Foo>
            {
                {"walterlv", new Foo("吕毅")},
                {"lindexi", new Foo("林德熙")},
            };
            var time = DateTime.Now.ToString("T");
            table.Add(time, new Foo("时间"));
            time = null;

            Console.WriteLine($"开始个数：{table.Count()}");
            GC.Collect();
            Console.WriteLine($"剩余个数：{table.Count()}");
        }
    }

    public class Foo
    {
        public string Value { get; }
        public Foo(string value) => Value = value;
    }
}

var a = "walterlv";
var b = "walterlv";
var c = "walterlv";

var a = "walterlv";
var b = new StringBuilder("walter").Append("lv").ToString();
var c = string.Intern(b);

Console.WriteLine(ReferenceEquals(a, b));
Console.WriteLine(ReferenceEquals(a, c));

[assembly: CompilationRelaxations(CompilationRelaxations.NoStringInterning)]

private Walterlv _foo;

[DebuggerBrowsable(DebuggerBrowsableState.Never)]
public Walterlv Walterlv => _foo ?? (_foo = new Walterlv());

public bool IsInitialized => !(_foo is null);

using System;
using System.Windows;

namespace Walterlv.Demo.DesktopDocking
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        protected override void OnSourceInitialized(EventArgs e)
        {
            base.OnSourceInitialized(e);
            DesktopAppBar.SetAppBar(this, AppBarEdge.Right);
        }
    }
}

DesktopAppBar.SetAppBar(this, AppBarEdge.None);

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
    {
        /// <summary>
        /// 标识 Window.AppBar 的附加属性。
        /// </summary>
        public static readonly DependencyProperty AppBarProperty = DependencyProperty.RegisterAttached(
            "AppBar", typeof(AppBarEdge), typeof(DesktopAppBar),
            new PropertyMetadata(AppBarEdge.None, OnAppBarEdgeChanged));

        /// <summary>
        /// 获取 <paramref name="window"/> 当前的停靠边缘。
        /// </summary>
        /// <param name="window">要获取停靠边缘的窗口。</param>
        /// <returns>停靠边缘。</returns>
        public static AppBarEdge GetAppBar(Window window) => (AppBarEdge)window.GetValue(AppBarProperty);

        /// <summary>
        /// 设置 <paramref name="window"/> 的停靠边缘方向。
        /// </summary>
        /// <param name="window">要设置停靠的窗口。</param>
        /// <param name="value">要设置的停靠边缘方向。</param>
        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);
        }
    }
}

class Foo
{
    // 请忽略这里公有字段带来的设计问题，只是为了演示。
    public string A;
}

class Foo
{
    public string A;
    public Bar Bar;
}

using System;
using System.Linq;
using System.Runtime.CompilerServices;

namespace Walterlv.Demo.Weak
{
    class Program
    {
        public static void Main()
        {
            var key1 = new Key("Key1");
            var key2 = new Key("Key2");
            var key3 = new Key("Key3");

            var table = new ConditionalWeakTable<Key, WalterlvValue>
            {
                {key1, new WalterlvValue()},
                {key2, new WalterlvValue()},
                {key3, new WalterlvValue()}
            };

            var weak2 = new WeakReference(key2);
            key2 = null;
            key3 = null;

            GC.Collect();

            Console.WriteLine($@"key1 = {key1?.ToString() ?? "null"}
key2 = {key2?.ToString() ?? "null"}, weak2 = {weak2.Target ?? "null"}
key3 = {key3?.ToString() ?? "null"}
Table = {{{string.Join(", ", table.Select(x => $"{x.Key} = {x.Value}"))}}}");
        }
    }

    public class Key
    {
        private readonly string _name;
        public Key(string name) => _name = name;
        public override string ToString() => _name;
    }

    public class WalterlvValue
    {
        public DateTime CreationTime = DateTime.Now;
        public override string ToString() => CreationTime.ToShortTimeString();
    }
}

if (DesignerProperties.GetIsInDesignMode(d))
{
    // 通常我们考虑在设计器中不做额外的任何事情是最偷懒不会出问题的代码了。
    return;
}

public static class WalterlvDesignTime
{
    /// <summary>
    /// 判断一个依赖对象是否是设计时的 <see cref="Window"/>。
    /// </summary>
    /// <param name="window">要被判断设计时的 <see cref="Window"/> 对象。</param>
    /// <returns>如果对象是设计时的 <see cref="Window"/>，则返回 true，否则返回 false。</returns>
    private static bool IsDesignTimeWindow(DependencyObject window)
    {
        const string vs201920172015Window =
            "Microsoft.VisualStudio.DesignTools.WpfDesigner.InstanceBuilders.WindowInstance";
        const string vs2013Window = "Microsoft.Expression.WpfPlatform.InstanceBuilders.WindowInstance";

        if (DesignerProperties.GetIsInDesignMode(window))
        {
            var typeName = window.GetType().FullName;
            if (Equals(vs201920172015Window, typeName) || Equals(vs2013Window, typeName))
            {
                return true;
            }
        }

        return false;
    }
}

if (WalterlvDesignTime.IsDesignTimeWindow(d))
{
    // 检测到如果是设计时的窗口，就跳过一些句柄等等一些真的需要一个窗口的代码调用。
}
else if (d is Window)
{
    // 检测到真的是窗口，做一些真实窗口初始化需要做的事情。
}
else
{
    // 这不是一个窗口，需要抛出异常。
}

var newTempFolder = @"C:\Walterlv\ApplicationTemp";
Environment.SetEnvironmentVariable("TEMP", newTempFolder);
Environment.SetEnvironmentVariable("TMP", newTempFolder);

var tempPath = Path.GetTempPath();

var tempPath = Path.GetTempFileName();