WPF实现背景透明磨砂，并通过HandyControl组件实现弹出等待框

前言：上一个版本的Winform需要改成WPF来做界面，第一次接触WPF，在转换过程中遇到的需求就是一个背景透明模糊，一个是类似于 加载中…… 这样的等待窗口，等后台执行完毕后再关掉。在Winform中是通过一个类指定等待窗口的parent为调用者，并指定topmost为最顶层来实现。在WPF中这个方法不太灵光，通过这几天的摸索，找到一个WPF下的UI利器--HandyControl（https://github.com/HandyOrg/HandyControl）感谢作者分享。通过它来实现一些界面的效果，它里面带的有个顶部弹出对话框的功能（带遮罩），但没找到后台代码关闭的方法。所以我就单独从里面把这个功能提取出来，实现了弹出提示框，后台可以关闭的模式。

先看一下HandyControl提供的Demo中的这种对话框。

由于我需要的是弹出后，后台会执行代码，代码执行完后主动关闭对话框的操作。于是我把里面的这块代码单独提取出来改造了一下，实现效果如下。

这是在新接触WPF开发中，学习到的，如何让主窗体背景磨砂透明、如何Grid背景透明模糊、如何让Grid的控件不随Grid来模糊。

下面进入代码：

首先新建一个WPF项目，然后通过Nuget引用HandyControl。

在App.xaml中添加以下内容，来引用HandyControl的样式效果。

    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary>
                    <ResourceDictionary.MergedDictionaries>
                        <ResourceDictionary Source="pack://application:,,,/HandyControl;component/Themes/SkinDefault.xaml"/>
                        <ResourceDictionary Source="pack://application:,,,/HandyControl;component/Themes/Theme.xaml"/>
                    </ResourceDictionary.MergedDictionaries>
                </ResourceDictionary>
                <ResourceDictionary>
                    <viewModel:ViewModelLocator x:Key="Locator" />
                </ResourceDictionary>
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>

　　添加一个类文件BlurBehind.cs，用来实现主窗体透明磨砂感。

using System;
using System.Runtime.InteropServices;

namespace WpfApp1
{
    /// <summary>
    /// 背景磨砂
    /// </summary>
    public class BlurBehind
    {
        internal enum AccentState
        {
            ACCENT_DISABLED = 1,
            ACCENT_ENABLE_GRADIENT = 0,
            ACCENT_ENABLE_TRANSPARENTGRADIENT = 2,
            ACCENT_ENABLE_BLURBEHIND = 3,
            ACCENT_INVALID_STATE = 4,
            ACCENT_ENABLE_ACRYLICBLURBEHIND = 5
        }

        [StructLayout(LayoutKind.Sequential)]
        internal struct AccentPolicy
        {
            public AccentState AccentState;
            public int AccentFlags;
            public int GradientColor;
            public int AnimationId;
        }

        [StructLayout(LayoutKind.Sequential)]
        internal struct WindowCompositionAttributeData
        {
            public WindowCompositionAttribute Attribute;
            public IntPtr Data;
            public int SizeOfData;
        }

        internal enum WindowCompositionAttribute
        {
            // ...
            WCA_ACCENT_POLICY = 19
            // ...
        }
    }
}

然后新建两个目录：ViewModel和Images

在Images中放入一张图片，并设置生成时自动复制

在ViewModel中新建三个类文件

DialogDemoViewModel.cs 用来实现弹出框

using System;
using GalaSoft.MvvmLight;
using GalaSoft.MvvmLight.Command;
using HandyControl.Controls;

namespace WpfApp1.ViewModel
{
    public class DialogDemoViewModel : ViewModelBase
    {
        private string _dialogResult;
        public string DialogResult
        {
            get => _dialogResult;
#if netle40
            set => Set(nameof(DialogResult), ref _dialogResult, value);
#else
            set => Set(ref _dialogResult, value);
#endif
        }
        public RelayCommand<TextDialog> ShowTextCmd => new Lazy<RelayCommand<TextDialog>>(() =>
            new RelayCommand<TextDialog>(ShowText)).Value;

        private static void ShowText(TextDialog d)
        {
            Dialog.Show(d);
            //获得句柄
            //var dialogShow = Dialog.Show(d);
            //var dialogShowHwnd = (HwndSource)PresentationSource.FromVisual(dialogShow);
            //if (dialogShowHwnd == null) return;
            //var hwnd = dialogShowHwnd.Handle;
        }
    }
}

　　DialogInfo.cs 用来实现数据绑定给弹出框，比如指定显示文字

using System.Windows.Automation.Peers;
using System.Windows.Automation.Provider;
using System.ComponentModel;

namespace WpfApp1.ViewModel
{
  public class DialogInfo : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        public DialogInfo()
        {
            MyTxt = "加载中，请稍后。";
        }
        private string myTxt;
        public string MyTxt
        {
            get => myTxt;
            set
            {
                myTxt = value;
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("MyTxt"));
            }
        }
    }
}

　　ViewModelLocator.cs用来实现构建弹出框实例

using System;
using System.Windows;
using CommonServiceLocator;
using GalaSoft.MvvmLight.Ioc;

namespace WpfApp1.ViewModel
{
    public class ViewModelLocator
    {
        public ViewModelLocator()
        {
            ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default);
            SimpleIoc.Default.Register<DialogDemoViewModel>();

        }

        public static ViewModelLocator Instance => new Lazy<ViewModelLocator>(() =>
            Application.Current.TryFindResource("Locator") as ViewModelLocator).Value;
        #region Vm
        public DialogDemoViewModel DialogDemo => ServiceLocator.Current.GetInstance<DialogDemoViewModel>();
        #endregion
    }
}

　　MainWindow.xaml 主窗体的内容

<Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    x:Class="WpfApp1.MainWindow"
    mc:Ignorable="d"
    Title="MainWindow" Height="450" Width="800"
    DataContext="{Binding DialogDemo,Source={StaticResource Locator}}"
    Loaded="MainWindow_OnLoaded"
    Background="#727A7A7A"
    AllowsTransparency="True"
    WindowStyle="None"
    MouseDown="MainWindow_OnMouseDown"
    >
    <Grid HorizontalAlignment="Left" Height="397" Margin="10,10,0,0" VerticalAlignment="Top" Width="790" ZIndex="0" >
        <Grid Margin="0,10,10,97">
            <Grid.Background>
                <ImageBrush ImageSource="/WpfApp1;component/Images/wow_cataclysm_artwork-wallpaper-960x540.jpg"></ImageBrush>
            </Grid.Background>
            <Grid.Effect>
                <BlurEffect Radius="8"></BlurEffect>
            </Grid.Effect>
        </Grid>
        <Button x:Name="Btn_Show" Content="Button" HorizontalAlignment="Left" Margin="430,185,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click"  />
        <TextBlock x:Name="txtBlock" HorizontalAlignment="Left" Margin="614,120,0,0" TextWrapping="Wrap" Text="" VerticalAlignment="Top" Height="120" Width="145" Foreground="White"/>
    </Grid>
</Window>

　　MainWindow.xaml.cs

using System;
using System.Linq;
using System.Runtime.InteropServices;
using System.Timers;
using System.Windows;
using System.Windows.Input;
using System.Windows.Interop;
using WpfApp1.ViewModel;
namespace WpfApp1
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow
    {
        [DllImport("user32.dll")]
        private static extern int SetWindowCompositionAttribute(IntPtr hwnd, ref BlurBehind.WindowCompositionAttributeData data);
        private uint _blurOpacity;
        public double BlurOpacity
        {
            get { return _blurOpacity; }
            set { _blurOpacity = (uint)value; EnableBlur(); }
        }

        private uint _blurBackgroundColor = 0x990000; /* BGR color format */
        public MainWindow()
        {
            InitializeComponent();
        }
        private void Button_Click(object sender, RoutedEventArgs e)
        {
            var newWindow = new TextDialog();
            var dialog = new DialogDemoViewModel();
            if (dialog.ShowTextCmd.CanExecute(newWindow))
            {
                dialog.ShowTextCmd.Execute(newWindow);
            }
            newWindow.info.MyTxt="加载中";
            //if (DataContext is DialogDemoViewModel MyVM && MyVM.ShowTextCmd.CanExecute(newWindow))
            //    MyVM.ShowTextCmd.Execute(newWindow);

            var i = 0;
            var timer = new Timer(1000);

            timer.Elapsed+=delegate
            {
                Dispatcher.BeginInvoke(new Action(() =>
                {
                    if (i < 5)
                    {
                        txtBlock.Text +=$"{5 - i}秒后关闭"+ Environment.NewLine;
                        i++;
                    }
                    else
                    {
                        newWindow.CloseMe();
                    }
                }));

            };
            timer.AutoReset = true;
            timer.Enabled = true;
        }
        /// <summary>
        ///     获取当前应用中处于激活的一个窗口
        /// </summary>
        /// <returns></returns>
        private static Window GetActiveWindow() => Application.Current.Windows.OfType<Window>().SingleOrDefault(x => x.IsActive);

        private void MainWindow_OnLoaded(object sender, RoutedEventArgs e)
        {
            EnableBlur();
        }

        private void EnableBlur()
        {
            var windowHelper = new WindowInteropHelper(this);

            var accent = new BlurBehind.AccentPolicy
            {
                AccentState = BlurBehind.AccentState.ACCENT_ENABLE_BLURBEHIND,
                //GradientColor = (int) ((_blurOpacity << 24) | (_blurBackgroundColor & 0xFFFFFF))
            };

            var accentStructSize = Marshal.SizeOf(accent);

            var accentPtr = Marshal.AllocHGlobal(accentStructSize);
            Marshal.StructureToPtr(accent, accentPtr, false);

            var data = new BlurBehind.WindowCompositionAttributeData
            {
                Attribute = BlurBehind.WindowCompositionAttribute.WCA_ACCENT_POLICY,
                SizeOfData = accentStructSize,
                Data = accentPtr
            };

            SetWindowCompositionAttribute(windowHelper.Handle, ref data);

            Marshal.FreeHGlobal(accentPtr);
        }

        private void MainWindow_OnMouseDown(object sender, MouseButtonEventArgs e)
        {
            if (e.ChangedButton == MouseButton.Left)
                DragMove();
        }
    }

}

　　TextDialog.xaml 对话框

<Border x:Class="WpfApp1.TextDialog"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:hc="https://handyorg.github.io/handycontrol"
        CornerRadius="10"
        Width="400"
        Height="247"
        Background="{DynamicResource RegionBrush}"
        >
    <hc:SimplePanel>
        <TextBlock x:Name="TextBlock" Style="{StaticResource TextBlockLargeBold}" Text="{Binding MyTxt,UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Left" Margin="100,0,0,119" VerticalAlignment="Bottom" Height="68" Width="100"/>
        <Button x:Name="BtnClose" Width="22" Height="22" Command="hc:ControlCommands.Close" Style="{StaticResource ButtonIcon}" Foreground="{DynamicResource PrimaryBrush}" hc:IconElement.Geometry="{StaticResource ErrorGeometry}" Padding="0" HorizontalAlignment="Right" VerticalAlignment="Top" Margin="0,4,4,0" Visibility="Hidden" />
    </hc:SimplePanel>
</Border>

　　TextDialog.xaml.cs 新增了一个CloseMe 用来后台调用关闭它

 using System.Windows.Automation.Peers;
 using System.Windows.Automation.Provider;
 using WpfApp1.ViewModel;

 namespace WpfApp1
 {
     /// <summary>
     /// TextDialog_.xaml 的交互逻辑
     /// </summary>
     public partial class TextDialog
     {
         public DialogInfo info = new DialogInfo { MyTxt = "加载中……" };
         public TextDialog()
         {
             DataContext = info;
             InitializeComponent();
         }
         public void CloseMe()
         {
             try
             {
                 BtnClose.Visibility = Visibility.Visible;
                 BtnClose.OnClick();
             }
             catch
             {
                 //
             }

         }
     }
     /// <summary>
     /// ButtonBase 扩展
     /// </summary>
     public static class ButtonBaseExtension
     {
         /// <summary>
         /// 引发 <see>
         /// <cref>Primitives.ButtonBase.Click</cref>
         /// </see>
         /// 路由事件。
         /// </summary>
         /// <param name="buttonBase">要引发路由事件的按钮</param>
         public static void OnClick(this System.Windows.Controls.Primitives.ButtonBase buttonBase)
         {
             buttonBase.GetType().GetMethod(nameof(OnClick), BindingFlags.Instance | BindingFlags.NonPublic)?.Invoke(buttonBase, null);
         }
     }

 }