基于WPF實(shí)現(xiàn)Message消息提醒控件

更新時(shí)間：2023年07月16日 08:47:41 作者：WPF開發(fā)者

這篇文章主要介紹了如何利用WPF實(shí)現(xiàn)Meesage消息提醒控件，文中的示例代碼講解詳細(xì)，對(duì)我們學(xué)習(xí)或工作有一定幫助，需要的可以參考一下

WPF 實(shí)現(xiàn) Message 消息提醒控件

框架使用.NET4 至 .NET6；
Visual Studio 2022;
接著上一篇

實(shí)現(xiàn)代碼

1）新增 MessageListBoxItem.cs 代碼如下:

新增了名為MessageType的依賴屬性，類型為MessageBoxImage，默認(rèn)值為MessageBoxImage.Information

新增了名為IsCenter的依賴屬性，默認(rèn)值為false，為true則內(nèi)容居中顯示。

using?System.Windows;
using?System.Windows.Controls;
namespace?WPFDevelopers.Controls
{
????public?class?MessageListBoxItem?:?ListBoxItem
????{
????????public?MessageBoxImage?MessageType
????????{
????????????get?{?return?(MessageBoxImage)GetValue(MessageTypeProperty);?}
????????????set?{?SetValue(MessageTypeProperty,?value);?}
????????}
????????public?static?readonly?DependencyProperty?MessageTypeProperty?=
????????????DependencyProperty.Register("MessageType",?typeof(MessageBoxImage),?typeof(MessageListBoxItem),?new?PropertyMetadata(MessageBoxImage.Information));
????????public?bool?IsCenter
????????{
????????????get?{?return?(bool)GetValue(IsCenterProperty);?}
????????????set?{?SetValue(IsCenterProperty,?value);?}
????????}
????????public?static?readonly?DependencyProperty?IsCenterProperty?=
????????????DependencyProperty.Register("IsCenter",?typeof(bool),?typeof(MessageListBoxItem),?new?PropertyMetadata(false));
????}
}

2）新增 MessageListBox.cs 代碼如下:

自定義MessageListBox繼承ListBox，其中重寫了兩個(gè)方法：IsItemItsOwnContainerOverride和GetContainerForItemOverride。

GetContainerForItemOverride方法用于創(chuàng)建并返回一個(gè)新的容器對(duì)象，用于承載列表框中的項(xiàng)。在這里，它創(chuàng)建并返回一個(gè)MessageListBoxItem的實(shí)例作為容器對(duì)象。

IsItemItsOwnContainerOverride方法用于確定給定的項(xiàng)是否應(yīng)該作為其自己的容器。在這里，它檢查傳入的item對(duì)象是否是MessageListBoxItem的實(shí)例。如果是，則返回true，表示該項(xiàng)是其自己的容器；否則，返回false。

using?System.Windows;
using?System.Windows.Controls;
namespace?WPFDevelopers.Controls
{
????public?class?MessageListBox?:?ListBox
????{
????????protected?override?bool?IsItemItsOwnContainerOverride(object?item)
????????{
????????????return?item?is?MessageListBoxItem;
????????}
????????protected?override?DependencyObject?GetContainerForItemOverride()
????????{
????????????return?new?MessageListBoxItem();
????????}
????}
}

3）新增 MessageAdorner.cs 代碼如下:

MessageAdorner是一個(gè)繼承自Adorner的自定義類。它用于在裝飾元素上顯示消息的附加裝飾器。

構(gòu)造函數(shù)MessageAdorner(UIElement adornedElement)接受一個(gè)UIElement類型的參數(shù)，作為要進(jìn)行裝飾的元素。

Push方法用于將消息添加到裝飾器中。它接受消息內(nèi)容、消息類型和是否居中顯示的參數(shù)。如果裝飾器尚未創(chuàng)建，則會(huì)創(chuàng)建一個(gè)MessageListBox并將其設(shè)置為裝飾器的子元素。然后，根據(jù)傳入的參數(shù)創(chuàng)建一個(gè)新的MessageListBoxItem，并將其插入到列表框的頂部。

Child屬性用于獲取或設(shè)置裝飾器的子元素。當(dāng)設(shè)置子元素時(shí)，會(huì)將子元素添加到裝飾器的可視化子元素集合中；當(dāng)子元素為null時(shí)，會(huì)從可視化子元素集合中移除子元素。

VisualChildrenCount屬性返回裝飾器的可視化子元素?cái)?shù)量。

ArrangeOverride方法用于調(diào)整裝飾器的布局。在這里，根據(jù)裝飾元素的寬度和子元素的期望大小，計(jì)算出子元素的水平位置，并將其排列在裝飾器的頂部。

GetVisualChild方法用于獲取指定索引處的可視化子元素。在這里，如果索引為0且子元素不為null，則返回子元素；否則，調(diào)用基類的方法返回對(duì)應(yīng)索引的可視化子元素。

using?System.Windows;
using?System.Windows.Documents;
using?System.Windows.Media;
namespace?WPFDevelopers.Controls
{
????public?class?MessageAdorner?:?Adorner
????{
????????private?MessageListBox?listBox;
????????private?UIElement?_child;
????????private?FrameworkElement?adornedElement;
????????public?MessageAdorner(UIElement?adornedElement)?:?base(adornedElement)
????????{
????????????this.adornedElement?=?adornedElement?as?FrameworkElement;
????????}
????????public?void?Push(string?message,?MessageBoxImage?type?=?MessageBoxImage.Information,?bool?center?=?false)
????????{
????????????if?(listBox?==?null)
????????????{
????????????????listBox?=?new?MessageListBox();
????????????????Child?=?listBox;
????????????}
????????????var?mItem?=?new?MessageListBoxItem?{?Content?=?message,?MessageType?=?type,?IsCenter?=?center?};
????????????listBox.Items.Insert(0,?mItem);
????????}
????????public?UIElement?Child
????????{
????????????get?=>?_child;
????????????set
????????????{
????????????????if?(value?==?null)
????????????????{
????????????????????RemoveVisualChild(_child);
????????????????????_child?=?value;
????????????????????return;
????????????????}
????????????????AddVisualChild(value);
????????????????_child?=?value;
????????????}
????????}
????????protected?override?int?VisualChildrenCount
????????{
????????????get
????????????{
????????????????return?_child?!=?null???1?:?0;
????????????}
????????}
????????protected?override?Size?ArrangeOverride(Size?finalSize)
????????{
????????????var?x?=?(adornedElement.ActualWidth?-?_child.DesiredSize.Width)?/?2;
????????????_child.Arrange(new?Rect(new?Point(x,?0),?_child.DesiredSize));
????????????return?finalSize;
????????}
????????protected?override?Visual?GetVisualChild(int?index)
????????{
????????????if?(index?==?0?&&?_child?!=?null)?return?_child;
????????????return?base.GetVisualChild(index);
????????}
????}
}

4）新增 Message.cs 代碼如下:

CreateMessageAdorner方法用于創(chuàng)建消息裝飾器MessageAdorner。它接受一些參數(shù)，如窗口所有者Window owner、消息內(nèi)容string message、消息類型MessageBoxImage type和是否居中顯示bool center。在方法內(nèi)部，它首先檢查是否已經(jīng)存在消息裝飾器實(shí)例messageAdorner，如果存在，則調(diào)用裝飾器的Push方法將新的消息添加到裝飾器中，并直接返回。如果不存在消息裝飾器實(shí)例，則根據(jù)提供的窗口所有者或獲取默認(rèn)窗口ControlsHelper.GetDefaultWindow()，然后獲取對(duì)應(yīng)的裝飾層AdornerLayer。如果裝飾層為空，則拋出異常。接著，創(chuàng)建一個(gè)新的消息裝飾器實(shí)例，并將其添加到裝飾層中。最后，調(diào)用裝飾器的Push方法將消息添加到裝飾器中。

Push方法是一個(gè)擴(kuò)展方法，用于在指定的窗口上顯示消息。它接受窗口對(duì)象Window owner作為第一個(gè)參數(shù)，以及其他參數(shù)，如消息內(nèi)容string message、消息類型MessageBoxImage type和是否居中顯示bool center。在方法內(nèi)部，它調(diào)用CreateMessageAdorner方法，并傳遞相應(yīng)的參數(shù)。

另一個(gè)重載的Push方法是直接在靜態(tài)上下文中調(diào)用的。它接受消息內(nèi)容string message、消息類型MessageBoxImage type和是否居中顯示bool center作為參數(shù)，并調(diào)用CreateMessageAdorner方法。

using?System;
using?System.Linq;
using?System.Windows;
using?WPFDevelopers.Helpers;
namespace?WPFDevelopers.Controls
{
????public?static?class?Message
????{
????????private?static?MessageAdorner?messageAdorner;
????????static?void?CreateMessageAdorner(Window?owner?=?null,?string?message?=?null,?MessageBoxImage?type?=?MessageBoxImage.Information,?bool?center?=?false)
????????{
????????????try
????????????{
????????????????if?(messageAdorner?!=?null)
????????????????{
????????????????????messageAdorner.Push(message,?type,?center);
????????????????????return;
????????????????}
????????????????if?(owner?==?null)
????????????????????owner?=?ControlsHelper.GetDefaultWindow();
????????????????var?layer?=?ControlsHelper.GetAdornerLayer(owner);
????????????????if?(layer?==?null)
????????????????????throw?new?Exception("not?AdornerLayer?is?null");
????????????????messageAdorner?=?new?MessageAdorner(layer);
????????????????layer.Add(messageAdorner);
????????????????messageAdorner.Push(message,?type,?center);
????????????}
????????????catch?(Exception)
????????????{
????????????????throw;
????????????}
????????}
????????public?static?void?Push(this?Window?owner,?string?message,?MessageBoxImage?type?=?MessageBoxImage.Information,?bool?center?=?false)
????????{
????????????CreateMessageAdorner(owner,?message,?type,?center);
????????}
????????public?static?void?Push(string?message,?MessageBoxImage?type?=?MessageBoxImage.Information,?bool?center?=?false)
????????{
????????????CreateMessageAdorner(message:?message,?type:?type,?center:?center);
????????}
????}
}

5）新增 MessageListBoxItem.xaml 代碼如下:

XAML 代碼定義一個(gè)名為Storyboard_Loaded的故事板（Storyboard），其中包含了四個(gè)DoubleAnimation 動(dòng)畫

第一個(gè)DoubleAnimation動(dòng)畫將目標(biāo)元素PART_SmallPanel的Y軸縮放屬性ScaleTransform.ScaleY 從 0 變化到 1，持續(xù)時(shí)間為0.2秒。這會(huì)使PART_SmallPanel在加載時(shí)以漸變的方式顯示出來(lái)。
第二個(gè)DoubleAnimation動(dòng)畫將目標(biāo)元素PART_SmallPanel的不透明度屬性Opacity從0.1變化到1，持續(xù)時(shí)間為0.2秒。這也是為了使PART_SmallPanel在加載時(shí)以漸變的方式顯示出來(lái)。
第三個(gè)DoubleAnimation動(dòng)畫將目標(biāo)元素PART_SmallPanel的Y軸縮放屬性ScaleTransform.ScaleY從1變化到0，持續(xù)時(shí)間為0.2秒。這個(gè)動(dòng)畫在10秒后開始執(zhí)行，會(huì)使PART_SmallPanel以漸變的方式從可見(jiàn)狀態(tài)變?yōu)椴豢梢?jiàn)狀態(tài)。
第四個(gè)DoubleAnimation動(dòng)畫將目標(biāo)元素PART_SmallPanel的不透明度屬性Opacity從1變化到0，持續(xù)時(shí)間為0.2秒。同樣地，在10秒后開始執(zhí)行，使PART_SmallPanel以漸變的方式從可見(jiàn)狀態(tài)變?yōu)椴豢梢?jiàn)狀態(tài)。

定義一個(gè)名為Storyboard_Close的故事板Storyboard，其中包含了兩個(gè)DoubleAnimation動(dòng)畫。

第一個(gè)DoubleAnimation動(dòng)畫將目標(biāo)元素PART_SmallPanel的Y軸縮放屬性(UIElement.RenderTransform).(ScaleTransform.ScaleY)從1變化到0，持續(xù)時(shí)間為0.2秒。這會(huì)使PART_SmallPanel以漸變的方式從可見(jiàn)狀態(tài)變?yōu)椴豢梢?jiàn)狀態(tài)。
第二個(gè)DoubleAnimation動(dòng)畫將目標(biāo)元素PART_SmallPanel的不透明度屬性(Opacity)從1變化到0，持續(xù)時(shí)間為0秒。該動(dòng)畫在0.2秒后開始執(zhí)行，使PART_SmallPanel以立即消失的方式從可見(jiàn)狀態(tài)變?yōu)椴豢梢?jiàn)狀態(tài)。

?<ResourceDictionary
????xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
????xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
????xmlns:controls="clr-namespace:WPFDevelopers.Controls"
????xmlns:helpers="clr-namespace:WPFDevelopers.Helpers">
????<ResourceDictionary.MergedDictionaries>
????????<ResourceDictionary?Source="Basic/ControlBasic.xaml"?/>
????</ResourceDictionary.MergedDictionaries>
????<Style
????????x:Key="WD.MessageListBoxItem"
????????BasedOn="{StaticResource?WD.ControlBasicStyle}"
????????TargetType="{x:Type?controls:MessageListBoxItem}">
????????<Setter?Property="FontSize"?Value="{DynamicResource?WD.NormalFontSize}"?/>
????????<Setter?Property="Foreground"?Value="{DynamicResource?WD.RegularTextSolidColorBrush}"?/>
????????<Setter?Property="Background"?Value="{DynamicResource?WD.BackgroundSolidColorBrush}"?/>
????????<Setter?Property="helpers:ListBoxItemExtensions.AutoRemoveOnOpacityZero"?Value="True"?/>
????????<Setter?Property="Width"?Value="300"?/>
????????<Setter?Property="Height"?Value="Auto"?/>
????????<Setter?Property="Padding"?Value="10"?/>
????????<Setter?Property="Margin"?Value="4,2"?/>
????????<Setter?Property="Template">
????????????<Setter.Value>
????????????????<ControlTemplate?TargetType="{x:Type?controls:MessageListBoxItem}">
????????????????????<ControlTemplate.Resources>
????????????????????????<Storyboard?x:Key="Storyboard_Close">
????????????????????????????<DoubleAnimation
????????????????????????????????Storyboard.TargetName="PART_SmallPanel"
????????????????????????????????Storyboard.TargetProperty="(UIElement.RenderTransform).(ScaleTransform.ScaleY)"
????????????????????????????????From="1"
????????????????????????????????To="0"
????????????????????????????????Duration="0:0:0.2"?/>
????????????????????????????<DoubleAnimation
????????????????????????????????BeginTime="0:0:0.2"
????????????????????????????????Storyboard.TargetProperty="Opacity"
????????????????????????????????From="1"
????????????????????????????????To="0"
????????????????????????????????Duration="0:0:0"?/>
????????????????????????</Storyboard>
????????????????????????<Storyboard?x:Key="Storyboard_Loaded">
????????????????????????????<DoubleAnimation
????????????????????????????????Storyboard.TargetName="PART_SmallPanel"
????????????????????????????????Storyboard.TargetProperty="(UIElement.RenderTransform).(ScaleTransform.ScaleY)"
????????????????????????????????From="0"
????????????????????????????????To="1"
????????????????????????????????Duration="0:0:0.2"?/>
????????????????????????????<DoubleAnimation
????????????????????????????????Storyboard.TargetName="PART_SmallPanel"
????????????????????????????????Storyboard.TargetProperty="Opacity"
????????????????????????????????From=".1"
????????????????????????????????To="1"
????????????????????????????????Duration="0:0:0.2"?/>
????????????????????????????<DoubleAnimation
????????????????????????????????BeginTime="0:0:10"
????????????????????????????????Storyboard.TargetName="PART_SmallPanel"
????????????????????????????????Storyboard.TargetProperty="(UIElement.RenderTransform).(ScaleTransform.ScaleY)"
????????????????????????????????From="1"
????????????????????????????????To="0"
????????????????????????????????Duration="0:0:0.2"?/>
????????????????????????????<DoubleAnimation
????????????????????????????????BeginTime="0:0:10"
????????????????????????????????Storyboard.TargetProperty="Opacity"
????????????????????????????????From="1"
????????????????????????????????To="0"
????????????????????????????????Duration="0:0:0.2"?/>
????????????????????????</Storyboard>
????????????????????</ControlTemplate.Resources>
????????????????????<controls:SmallPanel
????????????????????????x:Name="PART_SmallPanel"
????????????????????????Margin="{TemplateBinding?Margin}"
????????????????????????RenderTransformOrigin=".5,0">
????????????????????????<controls:SmallPanel.RenderTransform>
????????????????????????????<ScaleTransform?/>
????????????????????????</controls:SmallPanel.RenderTransform>
????????????????????????<Border
????????????????????????????x:Name="PART_Border"
????????????????????????????Background="{TemplateBinding?Background}"
????????????????????????????BorderBrush="{TemplateBinding?BorderBrush}"
????????????????????????????BorderThickness="{TemplateBinding?BorderThickness}"
????????????????????????????CornerRadius="{Binding?Path=(helpers:ElementHelper.CornerRadius),?RelativeSource={RelativeSource?TemplatedParent}}"
????????????????????????????Effect="{StaticResource?WD.NormalShadowDepth}"
????????????????????????????SnapsToDevicePixels="True"
????????????????????????????UseLayoutRounding="True"?/>
????????????????????????<Border?Padding="{TemplateBinding?Padding}">
????????????????????????????<Grid>
????????????????????????????????<Grid.ColumnDefinitions>
????????????????????????????????????<ColumnDefinition?Width="*"?/>
????????????????????????????????????<ColumnDefinition?Width="Auto"?/>
????????????????????????????????</Grid.ColumnDefinitions>
????????????????????????????????<DockPanel?x:Name="PART_DockPanel"?Grid.Column="0">
????????????????????????????????????<Path
????????????????????????????????????????x:Name="PART_Path"
????????????????????????????????????????Width="15"
????????????????????????????????????????Height="15"
????????????????????????????????????????Data="{StaticResource?WD.InformationGeometry}"
????????????????????????????????????????Fill="{DynamicResource?WD.PrimaryNormalSolidColorBrush}"
????????????????????????????????????????Stretch="Fill"?/>
????????????????????????????????????<TextBlock
????????????????????????????????????????Grid.Column="1"
????????????????????????????????????????Margin="5,0,0,0"
????????????????????????????????????????VerticalAlignment="Center"
????????????????????????????????????????FontSize="{TemplateBinding?FontSize}"
????????????????????????????????????????Foreground="{TemplateBinding?Foreground}"
????????????????????????????????????????Text="{TemplateBinding?Content}"
????????????????????????????????????????TextWrapping="Wrap"?/>
????????????????????????????????</DockPanel>
????????????????????????????????<Button
????????????????????????????????????x:Name="PART_CloseButton"
????????????????????????????????????Grid.Column="2"
????????????????????????????????????Width="30"
????????????????????????????????????Height="28"
????????????????????????????????????Padding="0"
????????????????????????????????????HorizontalAlignment="Right"
????????????????????????????????????Style="{StaticResource?WD.PathButton}">
????????????????????????????????????<Path
????????????????????????????????????????Width="10"
????????????????????????????????????????Height="10"
????????????????????????????????????????HorizontalAlignment="Center"
????????????????????????????????????????VerticalAlignment="Center"
????????????????????????????????????????Data="{DynamicResource?WD.WindowCloseGeometry}"
????????????????????????????????????????Fill="{DynamicResource?WD.SecondaryTextSolidColorBrush}"
????????????????????????????????????????Stretch="Fill"?/>
????????????????????????????????</Button>
????????????????????????????</Grid>
????????????????????????</Border>
????????????????????</controls:SmallPanel>
????????????????????<ControlTemplate.Triggers>
????????????????????????<Trigger?Property="MessageType"?Value="Warning">
????????????????????????????<Setter?TargetName="PART_Path"?Property="Data"?Value="{StaticResource?WD.WarningGeometry}"?/>
????????????????????????????<Setter?TargetName="PART_Path"?Property="Fill"?Value="{StaticResource?WD.WarningSolidColorBrush}"?/>
????????????????????????????<Setter?Property="Foreground"?Value="{StaticResource?WD.WarningSolidColorBrush}"?/>
????????????????????????</Trigger>
????????????????????????<Trigger?Property="MessageType"?Value="Error">
????????????????????????????<Setter?TargetName="PART_Path"?Property="Data"?Value="{StaticResource?WD.ErrorGeometry}"?/>
????????????????????????????<Setter?TargetName="PART_Path"?Property="Fill"?Value="{StaticResource?WD.DangerSolidColorBrush}"?/>
????????????????????????????<Setter?Property="Foreground"?Value="{StaticResource?WD.DangerSolidColorBrush}"?/>
????????????????????????</Trigger>
????????????????????????<Trigger?Property="MessageType"?Value="Information">
????????????????????????????<Setter?TargetName="PART_Path"?Property="Data"?Value="{StaticResource?WD.InformationGeometry}"?/>
????????????????????????????<Setter?TargetName="PART_Path"?Property="Fill"?Value="{StaticResource?WD.SuccessSolidColorBrush}"?/>
????????????????????????????<Setter?Property="Foreground"?Value="{StaticResource?WD.SuccessSolidColorBrush}"?/>
????????????????????????</Trigger>
????????????????????????<Trigger?Property="MessageType"?Value="Question">
????????????????????????????<Setter?TargetName="PART_Path"?Property="Data"?Value="{StaticResource?WD.QuestionGeometry}"?/>
????????????????????????????<Setter?TargetName="PART_Path"?Property="Fill"?Value="{StaticResource?WD.NormalSolidColorBrush}"?/>
????????????????????????????<Setter?Property="Foreground"?Value="{StaticResource?WD.NormalSolidColorBrush}"?/>
????????????????????????</Trigger>
????????????????????????<Trigger?Property="IsCenter"?Value="True">
????????????????????????????<Setter?TargetName="PART_DockPanel"?Property="HorizontalAlignment"?Value="Center"?/>
????????????????????????</Trigger>
????????????????????????<EventTrigger?RoutedEvent="Button.Click"?SourceName="PART_CloseButton">
????????????????????????????<BeginStoryboard?x:Name="BeginStoryboardClose"?Storyboard="{StaticResource?Storyboard_Close}"?/>
????????????????????????</EventTrigger>
????????????????????????<EventTrigger?RoutedEvent="Loaded">
????????????????????????????<BeginStoryboard?x:Name="BeginStoryboardLoaded"?Storyboard="{StaticResource?Storyboard_Loaded}"?/>
????????????????????????</EventTrigger>
????????????????????????<EventTrigger?RoutedEvent="Unloaded">
????????????????????????????<StopStoryboard?BeginStoryboardName="BeginStoryboardLoaded"?/>
????????????????????????????<StopStoryboard?BeginStoryboardName="BeginStoryboardClose"?/>
????????????????????????</EventTrigger>
????????????????????????<Trigger?Property="Opacity"?Value="0">
????????????????????????????<Setter?Property="Visibility"?Value="Collapsed"?/>
????????????????????????</Trigger>
????????????????????</ControlTemplate.Triggers>
????????????????</ControlTemplate>
????????????</Setter.Value>
????????</Setter>
????</Style>
????<Style?x:Key="WD.MessageListBox"?TargetType="{x:Type?controls:MessageListBox}">
????????<Setter?Property="BorderThickness"?Value="0"?/>
????????<Setter?Property="Background"?Value="Transparent"?/>
????????<Setter?Property="ScrollViewer.VerticalScrollBarVisibility"?Value="Hidden"?/>
????</Style>
????<Style?BasedOn="{StaticResource?WD.MessageListBoxItem}"?TargetType="{x:Type?controls:MessageListBoxItem}"?/>
????<Style?BasedOn="{StaticResource?WD.MessageListBox}"?TargetType="{x:Type?controls:MessageListBox}"?/>
</ResourceDictionary>

6）新增 ListBoxItemExtensions 代碼如下：

在方法內(nèi)部，首先將sender轉(zhuǎn)換為ListBoxItem類型，并進(jìn)行空引用檢查。然后，創(chuàng)建一個(gè)綁定對(duì)象binding，將其源設(shè)置為當(dāng)前的item，并將綁定模式設(shè)置為單向。

接下來(lái)，使用DependencyPropertyDescriptor從UIElement.OpacityProperty屬性獲取一個(gè)依賴屬性描述符dpd。通過(guò)調(diào)用AddValueChanged方法，將一個(gè)值更改事件的處理程序添加到item上。當(dāng)item的不透明度Opacity小于0.1時(shí)，該處理程序?qū)?zhí)行以下操作：

獲取父級(jí)ItemsControl，即包含item的列表框。
如果找到了父級(jí)ItemsControl，則使用ItemContainerGenerator從item獲取關(guān)聯(lián)的數(shù)據(jù)項(xiàng)（selectedItem）。
從父級(jí)ItemsControl的Items集合中移除selectedItem。
調(diào)用父級(jí)ItemsControl的Refresh方法，以刷新列表框的顯示。

using?System.ComponentModel;
using?System.Windows;
using?System.Windows.Controls;
using?System.Windows.Data;
namespace?WPFDevelopers.Helpers
{
????public?static?class?ListBoxItemExtensions
????{
????????public?static?readonly?DependencyProperty?AutoRemoveOnOpacityZeroProperty?=
????????DependencyProperty.RegisterAttached("AutoRemoveOnOpacityZero",?typeof(bool),?typeof(ListBoxItemExtensions),?new?PropertyMetadata(false,?OnAutoRemoveOnOpacityZeroChanged));
????????public?static?bool?GetAutoRemoveOnOpacityZero(DependencyObject?obj)
????????{
????????????return?(bool)obj.GetValue(AutoRemoveOnOpacityZeroProperty);
????????}
????????public?static?void?SetAutoRemoveOnOpacityZero(DependencyObject?obj,?bool?value)
????????{
????????????obj.SetValue(AutoRemoveOnOpacityZeroProperty,?value);
????????}
????????private?static?void?OnAutoRemoveOnOpacityZeroChanged(DependencyObject?obj,?DependencyPropertyChangedEventArgs?e)
????????{
????????????ListBoxItem?item?=?obj?as?ListBoxItem;
????????????if?(item?!=?null)
????????????{
????????????????if?((bool)e.NewValue)
????????????????????item.Loaded?+=?Item_Loaded;
????????????????else
????????????????????item.Loaded?-=?Item_Loaded;
????????????}
????????}
????????private?static?void?Item_Loaded(object?sender,?RoutedEventArgs?e)
????????{
????????????var?item?=?sender?as?ListBoxItem;
????????????if?(item?!=?null)
????????????{
????????????????var?binding?=?new?Binding("Opacity");
????????????????binding.Source?=?item;
????????????????binding.Mode?=?BindingMode.OneWay;
????????????????var?dpd?=?DependencyPropertyDescriptor.FromProperty(UIElement.OpacityProperty,?typeof(UIElement));
????????????????dpd.AddValueChanged(item,?(s,?args)?=>
????????????????{
????????????????????if?(item.Opacity?<?0.1)
????????????????????{
????????????????????????var?parent?=?ItemsControl.ItemsControlFromItemContainer(item);
????????????????????????if?(parent?!=?null)
????????????????????????{
????????????????????????????object?selectedItem?=?parent.ItemContainerGenerator.ItemFromContainer(item);
????????????????????????????parent.Items.Remove(selectedItem);
????????????????????????????parent.Items.Refresh();
????????????????????????}
????????????????????}
????????????????});
????????????}
????????}
????}
}

7）新增示例代碼如下:

<wd:Window
????x:Class="MessageSample.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:local="clr-namespace:MessageSample"
????xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
????xmlns:wd="https://github.com/WPFDevelopersOrg/WPFDevelopers"
????Title="WPFDevelopers?-?Message"
????Width="800"
????Height="450"
????mc:Ignorable="d">
????<Grid>
????????<StackPanel
????????????Grid.Row="1"
????????????HorizontalAlignment="Center"
????????????VerticalAlignment="Bottom"
????????????Orientation="Horizontal">
????????????<Button
????????????????Click="AddButton_Click"
????????????????Content="Info?Message"
????????????????Style="{StaticResource?WD.SuccessPrimaryButton}"
????????????????Tag="Info"?/>
????????????<Button
????????????????Click="AddButton_Click"
????????????????Content="Error?Message"
????????????????Style="{StaticResource?WD.DangerPrimaryButton}"
????????????????Tag="Error"?/>
????????????<Button
????????????????Click="AddButton_Click"
????????????????Content="Warning?Message"
????????????????Style="{StaticResource?WD.WarningPrimaryButton}"
????????????????Tag="Warning"?/>
????????????<Button
????????????????Click="AddButton_Click"
????????????????Content="Question?Message"
????????????????Style="{StaticResource?WD.PrimaryButton}"
????????????????Tag="Question"?/>
????????????<Button
????????????????Click="AddButton_Click"
????????????????Content="Long?Message"
????????????????Style="{StaticResource?WD.SuccessPrimaryButton}"
????????????????Tag="Long"?/>
????????</StackPanel>
????</Grid>
</wd:Window>

8）示例代碼如下:

private?void?AddButton_Click(object?sender,?RoutedEventArgs?e)
????????{
????????????var?btn?=?sender?as?Button;
????????????switch?(btn.Tag)
????????????{
????????????????case?"Info":
????????????????????Message.Push(App.Current.MainWindow,?"This?is?a?info?message",?MessageBoxImage.Information);
????????????????????break;
????????????????case?"Error":
????????????????????Message.Push("This?is?a?error?message",?MessageBoxImage.Error,?true);
????????????????????break;
????????????????case?"Warning":
????????????????????Message.Push("This?is?a?warning?message",?MessageBoxImage.Warning,?true);
????????????????????break;
????????????????case?"Question":
????????????????????Message.Push("This?is?a?question?message",?MessageBoxImage.Question);
????????????????????break;
????????????????default:
????????????????????Message.Push("這是一條很長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)長(zhǎng)消息",?MessageBoxImage.Information);
????????????????????break;
????????????}
????????}

效果圖