WPF:依赖属性的应用

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依赖属性与一般属性相比，提供了对资源引用、样式、动画、数据绑定、属性值继承、元数据重载以及WPF设计器的继承支持功能的支持。

下面的这个Demo来自《葵花宝典--WPF自学手册》。

1、MainWindow.xaml

<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:sys="clr-namespace:System;assembly=mscorlib"
xmlns:local="clr-namespace:WpfApplication1"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<SolidColorBrush x:Key="MyBrush" Color="Gold"/>
<Style x:Key="GreenButtonStyle">
<Setter Property="Control.Background" Value="Green"/>
</Style>
<local:BindingData x:Key="myDataSource"> </local:BindingData>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions> <Label HorizontalAlignment="Center" VerticalAlignment="Center">
资源支持
</Label>

<Button Grid.Row="0" Grid.Column="1" Name="resourceBtn" Background="{DynamicResource MyBrush}">
金色按钮
</Button>
<Label Grid.Row="0" Grid.Column="2" HorizontalAlignment="Center" VerticalAlignment="Center">
样式支持
</Label>

<Button Grid.Row="0" Grid.Column="3" Name="typeBtn" Style="{StaticResource GreenButtonStyle}">
绿色按钮
</Button>
<Label Grid.Row="1" Grid.Column="0" HorizontalAlignment="Center" VerticalAlignment="Center">
动画支持
</Label>

<Button Grid.Row="1" Grid.Column="1" Name="animationBtn">
动画按钮
<Button.Background>
<SolidColorBrush x:Name="AnimBrush"/>
</Button.Background>
<Button.Triggers>
<EventTrigger RoutedEvent="Button.Loaded">
<BeginStoryboard>
<Storyboard>
<ColorAnimation Storyboard.TargetName="AnimBrush"
Storyboard.TargetProperty="(SolidColorBrush.Color)"
From="Red" To="Green" Duration="0:0:5"
AutoReverse="True" RepeatBehavior="Forever"/>
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</Button.Triggers>
</Button>
<Label Grid.Row="1" Grid.Column="2" HorizontalAlignment="Center" VerticalAlignment="Center">
数据绑定支持
</Label>

<Button Grid.Row="1" Grid.Column="3" Name="bindingBtn" Background="{Binding Source={StaticResource myDataSource},Path=ColorName}">
被绑定为红色!
</Button>

<Label Grid.Row="2" Grid.Column="0" HorizontalAlignment="Center" VerticalAlignment="Center">
属性继承支持
</Label>
<Button Grid.Row="2" Grid.Column="1" Name="FontSizeWinBtn" Click="FontSizeWinBtn_Click">
设置窗口字体:16
</Button>
<Button Grid.Row="2" Grid.Column="2" Name="FontSizeBtn" Click="FontSizeBtn_Click">
设置按钮字体:8
</Button>
<Button Grid.Row="2" Grid.Column="3" Name="ResetFontSizeBtn" Click="ResetFontSizeBtn_Click">
重置窗口字体:12
</Button>
</Grid> </Window>

2、BindingData.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks; namespace WpfApplication1
{
class BindingData
{
public BindingData()
{
ColorName = "Red";
} private string name = "Red";
public string ColorName
{
get { return name; }
set
{
name = value; }
}
}
}

3、MainWindow.xaml.cs

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.Navigation;
using System.Windows.Shapes; namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
private double _oldFontSize = 0;
public MainWindow()
{
InitializeComponent(); _oldFontSize = FontSize;
}
//改变窗体所有元素的字体大小
private void FontSizeWinBtn_Click(object sender, RoutedEventArgs e)
{
FontSize = 16;
}
//仅改变该按钮的字体大小
private void FontSizeBtn_Click(object sender, RoutedEventArgs e)
{
this.FontSizeBtn.FontSize = 8;
}
//恢复字体大小
private void ResetFontSizeBtn_Click(object sender, RoutedEventArgs e)
{
FontSize = _oldFontSize;
this.FontSizeBtn.FontSize = _oldFontSize;
} }
}