D23_05_改变形状窗口的尺寸（自定义窗体大小改变）

<Window x:Class="demo.ModernWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="ModernWindow" Height="300" Width="300"
AllowsTransparency="True"
WindowStyle="None"
ResizeMode="CanResizeWithGrip"
Background="Transparent">
<Border Width="Auto" Height="Auto" Name="windowFrame"

BorderBrush="#395984"
BorderThickness="1"
CornerRadius="0,20,30,40" >
<Border.Background>
<LinearGradientBrush >
<GradientBrush.GradientStops>
<GradientStopCollection>
<GradientStop Color="#E7EBF7" Offset="0.0"/>
<GradientStop Color="#CEE3FF" Offset="0.5"/>

</GradientStopCollection>
</GradientBrush.GradientStops>
</LinearGradientBrush>
</Border.Background>
<Grid>

<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
</Grid.RowDefinitions>

<TextBlock Text="Title Bar" Margin="1" Padding="5" MouseLeftButtonDown="titleBar_MouseLeftButtonDown"></TextBlock>
<Grid Background="#B5CBEF" Grid.Row="1">
<Grid.RowDefinitions>
<RowDefinition></RowDefinition>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>

<TextBlock VerticalAlignment="Center" HorizontalAlignment="Center" Foreground="White" FontSize="20">Content Goes Here</TextBlock>
<Button VerticalAlignment="Top" HorizontalAlignment="Center" Padding="10" Grid.Row="1" Click="cmdClose_Click">Close</Button>
</Grid>
<TextBlock HorizontalAlignment="Center" Grid.Row="2" Text="Footer" Margin="1,10,1,1" Padding="5"></TextBlock>
<Rectangle Grid.RowSpan="3" Cursor="SizeWE" Fill="Transparent" Width="5" VerticalAlignment="Stretch"
HorizontalAlignment="Right" MouseLeftButtonDown="window_initateWiden"
MouseLeftButtonUp="window_endWiden"
MouseMove="window_Widen">
</Rectangle>
</Grid>

</Border>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
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 demo
{
/// <summary>
/// ModernWindow.xaml 的交互逻辑
/// </summary>
public partial class ModernWindow : Window
{
public ModernWindow()
{
InitializeComponent();
}

bool isWiden = false;
private void window_initateWiden(object sender, System.Windows.Input.MouseEventArgs e)
{
isWiden = true;
}

private void window_Widen(object sender,System.Windows.Input.MouseEventArgs e)
{
Rectangle rect=(Rectangle)sender;
if(isWiden)
{
rect.CaptureMouse();
double newWidth = e.GetPosition(this).X + 5;
if (newWidth > 0) this.Width = newWidth;
}
}

private void window_endWiden(object sender,System.Windows.Input.MouseEventArgs e)
{
isWiden=false;
Rectangle rect=(Rectangle)sender;
rect.ReleaseMouseCapture();
}

private void cmdClose_Click(object sender,RoutedEventArgs e)
{
this.Close();
}

private void titleBar_MouseLeftButtonDown(object sender,MouseButtonEventArgs e)
{
this.DragMove();
}
}
}