C# wpf利用附加属性实现界面上定义装饰器

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2023-07-06
基于C#实现鼠标设置功能
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标签   C# WPF
目录
  • 前言
  • 一、如何实现
  • 1、实现装饰器
  • 2、定义附加属性
  • 3、加入装饰层
  • 二、完整代码
  • 三、使用示例
  • 总结

前言

装饰器是wpf中可以浮在控件上面的一种组件，我们通常可以用来实现一些诸如控件拖动点、提示框、自定义鼠标等界面功能。装饰器的用法其实还是比较复杂的，几乎需要完全再cs中编写所有代码，对于样式要求较高的情况下，完全在cs中些控件的样式是比较困难的。为了改变这种状况，我们可以使用附加属性将装饰器的逻辑封装，提供一个可以在界面上定义的属性。

一、如何实现

1、实现装饰器

由于Adorner是一个抽象类不能直接实现，所有我们需要定义一个子类实现并它。

class NormalAdorner : Adorner
{
    /// <summary>
    /// 构造方法
    /// </summary>
    /// <param name="adornedElement">被添加装饰器的元素</param>
    /// <param name="child">放到装饰器中的元素</param>
    public NormalAdorner(UIElement adornedElement, UIElement child) : base(adornedElement);
    protected override Visual GetVisualChild(int index);
    protected override int VisualChildrenCount;
    protected override Size ArrangeOverride(Size finalSize);
}

2、定义附加属性

通过propa快捷定义一个名称为AdornerContent的附加属性其类型UIElement。

public static UIElementGetAdornerContent(DependencyObject obj)
{
    return (UIElement)obj.GetValue(AdornerContent);
}
public static void SetAdornerContent(DependencyObject obj, Control value)
{
    obj.SetValue(AdornerContent, value);
}
// Using a DependencyProperty as the backing store for MyProperty.  This enables animation, styling, binding, etc...
public static readonly DependencyProperty AdornerContent =
    DependencyProperty.RegisterAttached("AdornerContent", typeof(UIElement), typeof(AdornerHelper), new PropertyMetadata(null));

3、加入装饰层

在附加属性改变事件中，进行装饰层的添加。

public void PropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
    var c = d as UIElement;
    //获取装饰层
    var layer = AdornerLayer.GetAdornerLayer(c);
    //添加装饰器
     layer.Add(new NormalAdorner(c, (UIElement)e.NewValue));
}

二、完整代码

AdornerHelper.cs

using System;
using System.Windows;
using System.Windows.Documents;
using System.Windows.Media;
namespace AC
{
    internal class AdornerHelper
    {
        public static UIElement GetAdornerContent(DependencyObject obj)
        {
            return (UIElement)obj.GetValue(AdornerContent);
        }
        public static void SetAdornerContent(DependencyObject obj, UIElement value)
        {
            obj.SetValue(AdornerContent, value);
        }
        // Using a DependencyProperty as the backing store for MyProperty.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty AdornerContent =
            DependencyProperty.RegisterAttached("AdornerContent", typeof(UIElement), typeof(AdornerHelper), new PropertyMetadata(null, (d, e) =>
            {
                var c = d as FrameworkElement;
                if (c == null)
                    return;
                var adronerContent = e.NewValue as UIElement;
                if (!c.IsLoaded)
                {
                    if (adronerContent != null)
                    {
                        RoutedEventHandler l = null;
                        l = (s, E) =>
                        {
                            var content = GetAdornerContent(c);
                            if (content != null)
                            {
                                var layer = AdornerLayer.GetAdornerLayer(c);
                                if (layer == null)
                                    throw new Exception("获取控件装饰层失败，控件可能没有装饰层！");
                                layer.Add(new NormalAdorner((UIElement)c, (UIElement)e.NewValue));
                            }
                            c.Loaded -= l;
                        };
                        c.Loaded += l;
                    }
                }
                else
                {
                    var layer = AdornerLayer.GetAdornerLayer(d as Visual);
                    if (layer == null)
                        throw new Exception("获取控件装饰层失败，控件可能没有装饰层！");
                    if (e.OldValue != null)
                    {
 
                        var adorners = layer.GetAdorners(c);
                        foreach (var i in adorners)
                        {
                            if (i is NormalAdorner)
                            {
                                var na = i as NormalAdorner;
                                if (na.Child == e.OldValue)
                                {
                                    layer.Remove(i);
                                    break;
                                }
                            }
                        }
                    }
                    if (adronerContent != null)
                    {
                        layer.Add(new NormalAdorner((UIElement)c, (UIElement)e.NewValue));
                    }
                }
            }));
 
        class NormalAdorner : Adorner
        {
            UIElement _child;
            /// <summary>
            /// 构造方法
            /// </summary>
            /// <param name="adornedElement">被添加装饰器的元素</param>
            /// <param name="child">放到装饰器中的元素</param>
            public NormalAdorner(UIElement adornedElement, UIElement child) : base(adornedElement)
            {
                _child = child;
                AddVisualChild(child);
            }
            public UIElement Child { get { return _child; } }
            protected override Visual GetVisualChild(int index)
            {
                return _child;
            }
            protected override int VisualChildrenCount
            {
                get
                {
                    return;
                }
            }
            protected override Size ArrangeOverride(Size finalSize)
            {
                _child.Arrange(new Rect(new Point(, 0), finalSize));
                return finalSize;
            }
        }
    }
}

三、使用示例

<Window x:Class="WpfApp.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx//xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx//xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/"
        xmlns:local="clr-namespace:WpfApp"
        xmlns:ac="clr-namespace:AC"
        mc:Ignorable="d"
        Title="MainWindow" Height="" Width="800"
        >
    <Grid>
        <Border Background="RoyalBlue" Width="" Height="180" CornerRadius="10">
             <!--添加装饰器-->
            <ac:AdornerHelper.AdornerContent>
                <Grid >
                    <Grid.Resources>
                        <Style TargetType="Thumb">
                            <Setter Property="Template">
                                <Setter.Value>
                                    <ControlTemplate TargetType="Thumb">
                                        <Border BorderBrush="Gray" BorderThickness="" CornerRadius="8"  Background="White"></Border>
                                    </ControlTemplate>
                                </Setter.Value>
                            </Setter>
                        </Style>
                    </Grid.Resources>
                    <!--左-->
                    <Thumb  Margin="-,0,0,0" Width="16" Height="16" HorizontalAlignment="Left" VerticalAlignment="Center" Cursor="SizeWE"/>
                    <!--上-->
                    <Thumb  Margin=",-8,0,0" Width="16" Height="16" HorizontalAlignment="Center" VerticalAlignment="Top" Cursor="SizeNS"/>
                    <!--右-->
                    <Thumb  Margin=",0,-8,0" Width="16" Height="16" HorizontalAlignment="Right" VerticalAlignment="Center" Cursor="SizeWE"/>
                    <!--下-->
                    <Thumb  Margin=",0,0,-8" Width="16" Height="16" HorizontalAlignment="Center" VerticalAlignment="Bottom" Cursor="SizeNS"/>
                    <!--左上-->
                    <Thumb  Margin="-,-8,0,0" Width="16" Height="16" HorizontalAlignment="Left" VerticalAlignment="Top" Cursor="SizeNWSE"/>
                    <!--右上-->
                    <Thumb  Margin=",-8,-8,0" Width="16" Height="16" HorizontalAlignment="Right" VerticalAlignment="Top"  Cursor="SizeNESW"/>
                    <!--右下-->
                    <Thumb  Margin=",0,-8,-8" Width="16" Height="16" HorizontalAlignment="Right" VerticalAlignment="Bottom"  Cursor="SizeNWSE"/>
                    <!--左下-->
                    <Thumb  Margin="-,0,0,-8" Width="16" Height="16" HorizontalAlignment="Left" VerticalAlignment="Bottom" Cursor="SizeNESW"/>
                </Grid>
            </ac:AdornerHelper.AdornerContent>
        </Border>
    </Grid>
</Window>

效果预览

基于C#实现鼠标设置功能
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C#实现带行数和标尺的RichTextBox
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