public partial class BaseWindow : Window

    {

        public BaseWindow() : base()

        {

            this.Closed += Window_Closed;

            this.WindowStartupLocation = WindowStartupLocation.CenterOwner;

            this.ResizeMode = ResizeMode.NoResize;

        }

        public void SyncComplete()

        {

            this.Dispatcher.Invoke(() =>

            {

                MessageBox.Show(this, "操作完成！", "提示");

            });

        }

        private void Window_Closed(object sender, EventArgs e)

        {

            //容器Grid

            Grid grid = this.Owner.Content as Grid;

            //父级窗体原来的内容

            UIElement original = VisualTreeHelper.GetChild(grid, ) as UIElement;

            //将父级窗体原来的内容在容器Grid中移除

            grid.Children.Remove(original);

            //赋给父级窗体

            this.Owner.Content = original;

        }

        public bool? ShowDialog(Window owner)

        {

            //蒙板

            Grid layer = new Grid() { Background = new SolidColorBrush(Color.FromArgb(, , , )) };

            //父级窗体原来的内容

            UIElement original = owner.Content as UIElement;

            owner.Content = null;

            //容器Grid

            Grid container = new Grid();

            container.Children.Add(original);//放入原来的内容

            container.Children.Add(layer);//在上面放一层蒙板

                                          //将装有原来内容和蒙板的容器赋给父级窗体

            owner.Content = container;

            this.Owner = owner;

            return this.ShowDialog();

        }

    }

<local:BaseWindow x:Class="Modules.wnd_TimeSync"

        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

        xmlns:local="clr-namespace:Modules"

        mc:Ignorable="d" WindowStyle="None" AllowsTransparency="True" Background="Transparent"

        Title="wnd_TimeSync" Height="20" Width="220" Closed="Window_Closed" >

    <StackPanel>

        <ProgressBar Name="pb" Height="20" Width="200" Maximum="100"></ProgressBar>

    </StackPanel>

</local:BaseWindow>

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading;

using System.Threading.Tasks;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Data;

using System.Windows.Documents;

using System.Windows.Input;

using System.Windows.Media;

using System.Windows.Media.Imaging;

using System.Windows.Shapes;

namespace Modules

{

    /// <summary>

    /// wnd_TimeSync.xaml 的交互逻辑

    /// </summary>

    public partial class wnd_TimeSync : BaseWindow

    {

        public wnd_TimeSync()

        {

            InitializeComponent();

        }

        public static void ShowDialog(Window owner)

        {

            //弹出消息框

            wnd_TimeSync box = new wnd_TimeSync();

            box.ShowDialog(owner);

        }

    }

}