<Style x:Key="for_noresize_window" TargetType="{x:Type Window}">

        <Setter Property="AllowsTransparency" Value="true"/>

        <Setter Property="Background" Value="Transparent"/>

        <Setter Property="FontFamily" Value="Consolas, Microsoft YaHei"/>

        <Setter Property="ResizeMode" Value="NoResize"/>

        <Setter Property="WindowStyle" Value="None"/>

        <Setter Property="Template">

            <Setter.Value>

                <ControlTemplate TargetType="{x:Type Window}">

                    <Grid Margin="10">

                        <Rectangle Fill="{DynamicResource {x:Static SystemColors.WindowBrushKey}}"

                               RadiusX="5" RadiusY="5">

                            <Rectangle.Effect>

                                <DropShadowEffect BlurRadius="10" ShadowDepth="0"/>

                            </Rectangle.Effect>

                        </Rectangle>

                        <Border Background="{TemplateBinding Background}"

                            BorderBrush="{TemplateBinding BorderBrush}"

                            BorderThickness="{TemplateBinding BorderThickness}"

                            Padding="{TemplateBinding Margin}"

                            SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"

                            CornerRadius="5">

                            <ContentPresenter />

                        </Border>

                    </Grid>

                </ControlTemplate>

            </Setter.Value>

        </Setter>

    </Style>

<Window x:Class="WpfTest.Window1"

        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:WpfTest"

        mc:Ignorable="d"

        Title="Window1"   Height="400" Width="500" WindowStyle="None" ResizeMode="NoResize" AllowsTransparency="True" BorderThickness="0" Style="{StaticResource for_noresize_window}">

    <Grid>

        <Grid.ColumnDefinitions>

            <ColumnDefinition/>

        </Grid.ColumnDefinitions>

        <Grid.RowDefinitions>

            <RowDefinition Height="43" />

            <RowDefinition />

        </Grid.RowDefinitions>

        <Border Grid.Row="0" Grid.Column="0" Background="#FF005BAE" CornerRadius="5,5,0,0" >

            <Grid HorizontalAlignment="Stretch" VerticalAlignment="Stretch" >

                <Grid.ColumnDefinitions>

                    <ColumnDefinition Width="250*" />

                    <ColumnDefinition Width="48*" />

                </Grid.ColumnDefinitions>

                <Label Grid.Row="0" Grid.Column="0" Content="窗口1" HorizontalContentAlignment="Left" VerticalContentAlignment="Center" Padding="20 0 0 0" FontSize="20" Foreground="White" Background="Transparent"/>

                <Button Grid.Row="0" Grid.Column="1" Width="23" Height="23" HorizontalAlignment="Right" VerticalAlignment="Center" Click="btn_close_Click" Margin="0,10,10,8">

                    <Button.Template>

                        <ControlTemplate>

                            <Label Foreground="White" FontSize="20" HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Cursor="Hand" Margin="-9,-9,-9,-6">

                                <Label.Background>

                                    <ImageBrush ImageSource="Images/cancel.png"></ImageBrush>

                                </Label.Background>

                            </Label>

                        </ControlTemplate>

                    </Button.Template>

                </Button>

            </Grid>

        </Border>

        <Grid Grid.Row="1" Grid.Column="0">

        </Grid>

    </Grid>

</Window>

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

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 WpfTest

{

    /// <summary>

    /// Window1.xaml 的交互逻辑

    /// </summary>

    public partial class Window1 : Window

    {

        public Window1()

        {

            InitializeComponent();

        }

        private void btn_close_Click(object sender, RoutedEventArgs e)

        {

            this.Close();

        }

    }

}