WPF中依赖属性及附加属性的概念及用法

完全来源于十月的寒流，感谢大佬讲解

依赖属性

由依赖属性提供的属性功能

与字段支持的属性不同，依赖属性扩展了属性的功能。通常，添加的功能表示或支持以下功能之一：

资源
数据绑定
样式
动画
元数据重写
属性值继承
WPF 设计器集成

csharp 复制代码

    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            CustomTextBox customTextBox = new CustomTextBox();
            customTextBox.IsHightLighted = true;

            customTextBox.SetValue(CustomTextBox.IsHightLightedProperty, true);
        }
    }

    public class CustomTextBox : TextBox
    {
        public bool IsHightLighted
        {
            get { return (bool)GetValue(IsHightLightedProperty); }
            set { SetValue(IsHightLightedProperty, value); }
        }

        public static readonly DependencyProperty IsHightLightedProperty =
            DependencyProperty.Register("IsHightLighted", typeof(bool), typeof(CustomTextBox), new PropertyMetadata(false));
    }

csharp 复制代码

#region HasText
public bool HasText => (bool)GetValue(HasTextProperty);

public static readonly DependencyProperty HasTextProperty;
public static readonly DependencyPropertyKey HasTextPropertyKey;

static CustomTextBox()
{
    HasTextPropertyKey = DependencyProperty.RegisterReadOnly(
        "HasText",
        typeof(bool),
        typeof(CustomTextBox),
        new PropertyMetadata(false)
        );
    HasTextProperty = HasTextPropertyKey.DependencyProperty;
}
#endregion

csharp 复制代码

<Window x:Class="Test_05.MainWindow"
        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:Test_05"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">

    <Window.Resources>
        <Style TargetType="local:CustomTextBox">
            <Style.Triggers>
                <Trigger Property="IsHightLighted" Value="True">
                    <Setter Property="Background" Value="Yellow"></Setter>
                </Trigger>
                <Trigger Property="IsHightLighted" Value="False">
                    <Setter Property="Background" Value="Blue"></Setter>
                </Trigger>
            </Style.Triggers>
        </Style>
    </Window.Resources>
    <StackPanel>
        <local:CustomTextBox Text="Hello World!" FontSize="30" IsHightLighted="True"></local:CustomTextBox>
    </StackPanel>
</Window>

附加属性

csharp 复制代码

    <StackPanel>
        <!--<local:CustomTextBox Text="Hello World!" FontSize="30" IsHightLighted="True"></local:CustomTextBox>-->
        <local:CustomTextBox Text="Hello World!" FontSize="30">
            <local:CustomTextBox.IsHightLighted>
                true
            </local:CustomTextBox.IsHightLighted>
            <Grid.Row>1</Grid.Row>
        </local:CustomTextBox>
    </StackPanel>

复制代码

<StackPanel>
    <local:CustomTextBox x:Name="aoteman" local:TextBoxHelper.Title="this is test" FontSize="30"
                         Text="{Binding RelativeSource={RelativeSource self}, Path=(local:TextBoxHelper.Title)}"></local:CustomTextBox>

    <!--<local:CustomTextBox x:Name="aoteman" FontSize="30"
                         Text="{Binding RelativeSource={RelativeSource self}, Path=(local:TextBoxHelper.Title)}"></local:CustomTextBox>-->
</StackPanel>

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        //TextBoxHelper.SetTitle(aoteman, "this is aoteman");
    }
}

public class CustomTextBox : TextBox
{
    public bool IsHightLighted
    {
        get { return (bool)GetValue(IsHightLightedProperty); }
        set { SetValue(IsHightLightedProperty, value); }
    }

    public static readonly DependencyProperty IsHightLightedProperty =
        DependencyProperty.Register("IsHightLighted", typeof(bool), typeof(CustomTextBox), new PropertyMetadata(false));

    public bool HasText => (bool)GetValue(HasTextProperty);

    public static readonly DependencyProperty HasTextProperty;
    public static readonly DependencyPropertyKey HasTextPropertyKey;

    static CustomTextBox()
    {
        HasTextPropertyKey = DependencyProperty.RegisterReadOnly(
            "HasText",
            typeof(bool),
            typeof(CustomTextBox),
            new PropertyMetadata(false)
            );
        HasTextProperty = HasTextPropertyKey.DependencyProperty;
    }
}

public class TextBoxHelper
{
    public static string GetTitle(DependencyObject obj)
    {
        return (string)obj.GetValue(TitleProperty);
    }

    public static void SetTitle(DependencyObject obj, string value)
    {
        obj.SetValue(TitleProperty, value);
    }

    // Using a DependencyProperty as the backing store for Title.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty TitleProperty =
        DependencyProperty.RegisterAttached("Title", typeof(string), typeof(TextBoxHelper), new PropertyMetadata(""));
}

TextBox HasText