消息對(duì)話框是UI界面中不可或缺的組成部分，用于給用戶一些提示，警告或者詢問的窗口。在WPF中，消息對(duì)話框是系統(tǒng)原生（user32.dll）的MessageBox，無法通過Style或者Template來修改消息對(duì)話框的外觀。因此，當(dāng)需要一個(gè)與應(yīng)用程序主題風(fēng)格一致的消息對(duì)話框時(shí)，只能自己動(dòng)手造輪子了。
確定“輪子”的功能
消息對(duì)話框的核心功能是向用戶顯示信息，并在用戶對(duì)消息進(jìn)行處理前中斷用戶的操作。根據(jù)常見的應(yīng)用場(chǎng)景，可以梳理出以下幾點(diǎn)功能：
- 支持的消息類型：提示信息、警告信息、錯(cuò)誤信息、詢問信息
- 支持的對(duì)話框類型：迷你模式（顯示簡(jiǎn)要信息并自動(dòng)關(guān)閉）、普通模式、完整模式（適用于消息內(nèi)容分層級(jí)顯示）
- 設(shè)置消息對(duì)話框是否將觸發(fā)源作為父窗體并顯示遮罩層
主要功能如下圖所示：![[WPF]動(dòng)手寫一個(gè)簡(jiǎn)單的消息對(duì)話框](https://imgs.yssmx.com/Uploads/2023/11/747173-1.gif)
開始造“輪子”
消息對(duì)話框本質(zhì)也是一個(gè)窗體，因此首先要做的是自定義一個(gè)彈窗的樣式，然后根據(jù)消息類型以及對(duì)話框類型定義相應(yīng)的模板。
自定義窗口外觀
標(biāo)準(zhǔn)的窗口由兩個(gè)重疊的矩形組成。外部矩形是非工作區(qū)，其中包括標(biāo)題欄按鈕(最小化、最大化和關(guān)閉) 、窗口邊框、調(diào)整大小和移動(dòng)行為、應(yīng)用程序圖標(biāo)和標(biāo)題以及系統(tǒng)菜單。它由操作系統(tǒng)的窗口管理器繪制和管理。其尺寸由標(biāo)準(zhǔn)操作系統(tǒng)設(shè)置決定。內(nèi)部矩形是工作區(qū)，也就是應(yīng)用程序的內(nèi)容。
自定義窗口外觀主要是針對(duì)非工作區(qū)，可以通過設(shè)置屬性WindowStyle為None，或者使用 WindowChrome類來自定義。這里我們使用前一種方法。
<!-- 彈出提示窗體模板 -->
<ControlTemplate x:Key="AlertDialogBaseTemplate" TargetType="{x:Type Window}">
<Border x:Name="border" Margin="0"
Background="White" CornerRadius="3"
RenderTransformOrigin="0.5,0.5">
<i:Interaction.Triggers>
<i:EventTrigger EventName="Loaded">
<helper:EventToCommand Command="{Binding LoadedCommand}" CommandParameter="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Window}}}" />
</i:EventTrigger>
</i:Interaction.Triggers>
<Border.RenderTransform>
<TransformGroup>
<ScaleTransform />
</TransformGroup>
</Border.RenderTransform>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<toolkit:ImageButton Grid.Row="0" Width="16" Height="16"
Margin="0,16,16,0"
HorizontalAlignment="Right"
VerticalAlignment="Bottom"
Command="{Binding CloseWinCommand}"
CommandParameter="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Window}}}"
DownImage="Images/AlterDialog/btnclose_hover.png"
HoverImage="Images/AlterDialog/btnclose_hover.png"
NormalImage="Images/AlterDialog/btnclose.png"
ToolTip="關(guān)閉"
Visibility="{Binding DialogMode, Converter={helper:EnumExcludeConverter}, ConverterParameter='Mini'}" />
<ContentPresenter Grid.Row="1" />
</Grid>
</Border>
</ControlTemplate>
<!-- 彈出提示窗體樣式 -->
<Style x:Key="AlterDailogBaseStyle" TargetType="{x:Type view:AlterDialogWindow}" BasedOn="{StaticResource BaseWindowStyle}">
<Setter Property="AllowsTransparency" Value="True" />
<Setter Property="Height" Value="180" />
<Setter Property="MaxHeight" Value="240" />
<Setter Property="MaxWidth" Value="400" />
<Setter Property="OverridesDefaultStyle" Value="True" />
<Setter Property="Template" Value="{StaticResource AlertDialogBaseTemplate}" />
<Setter Property="Topmost" Value="False" />
<Setter Property="Width" Value="400" />
<Setter Property="WindowState" Value="Normal" />
<Setter Property="WindowStyle" Value="None" />
</Style>
<Style TargetType="{x:Type view:AlterDialogWindow}" BasedOn="{StaticResource AlterDailogBaseStyle}" />
上述代碼中，通過把WindowStyle屬性設(shè)置為None來隱藏默認(rèn)的非工作區(qū)（控制區(qū)），然后再窗口的Template中定義一個(gè)兩行的Grid，第一行模擬窗口非工作區(qū)的標(biāo)題欄，本例中僅放一個(gè)關(guān)閉按鈕。第二行則是工作區(qū)。
分享一個(gè)小小的經(jīng)驗(yàn)：在定義
AlterDialogWindow樣式的時(shí)候，最后一行代碼僅僅是定義了一個(gè)TargetType為view:AlterDialogWindow的樣式，并且通過BasedOn繼承自x:Key="AlterDailogBaseStyle"的樣式。這樣做并非多此一舉，而是為了方便局部需要個(gè)性化樣式時(shí)最大限度地復(fù)用默認(rèn)的全局樣式。
自定義消息對(duì)話框模板
消息對(duì)話框整體可以劃分為信息區(qū)域和交互區(qū)域兩部分。信息區(qū)域呈現(xiàn)消息類型和消息內(nèi)容，交互區(qū)域用于呈現(xiàn)確定和取消按鈕。信息區(qū)域的布局及大小與對(duì)話框類型相關(guān)。交互區(qū)域則與消息類型以及對(duì)話框類型都有關(guān)。提示、警告、錯(cuò)誤這三類消息是通知警示的作用，不需要用戶做出YES or NO的處理，僅需要顯示確定按鈕即可，詢問類信息則需要顯示確定和取消兩個(gè)按鈕。迷你模式的對(duì)話框則不需顯示確定和取消按鈕，因此整個(gè)交互區(qū)都不顯示。
根據(jù)三種類型的對(duì)話框定義三個(gè)信息區(qū)域的模板：
<DataTemplate x:Key="TemplateMini">
<StackPanel Margin="40,15,40,15" HorizontalAlignment="Center" Orientation="Horizontal">
<StackPanel.Resources>
<Style TargetType="{x:Type TextBlock}">
<Setter Property="FontSize" Value="18" />
<Setter Property="VerticalAlignment" Value="Center" />
</Style>
<Style TargetType="{x:Type toolkit:SelectableTextBlock}">
<Setter Property="FontSize" Value="18" />
<Setter Property="VerticalAlignment" Value="Center" />
</Style>
</StackPanel.Resources>
<Image Width="32" Height="34"
HorizontalAlignment="Right"
RenderOptions.BitmapScalingMode="LowQuality"
RenderOptions.CachingHint="Cache"
SnapsToDevicePixels="False"
Source="{Binding DialogType, Converter={StaticResource AlterDialogWindow_IconConverter}}"
Stretch="UniformToFill" />
<ScrollViewer MaxWidth="300" HorizontalScrollBarVisibility="Disabled" VerticalScrollBarVisibility="Auto">
<toolkit:SelectableTextBlock Margin="0,0,0,0"
HorizontalAlignment="Left" FontSize="18"
Foreground="#333333"
Text="{Binding Content}"
TextWrapping="Wrap" />
</ScrollViewer>
</StackPanel>
</DataTemplate>
<DataTemplate x:Key="TemplateNormal">
<StackPanel Margin="40,18,40,0" HorizontalAlignment="Center" VerticalAlignment="Top" Orientation="Horizontal">
<StackPanel.Resources>
<Style TargetType="{x:Type TextBlock}">
<Setter Property="FontSize" Value="18" />
<Setter Property="VerticalAlignment" Value="Center" />
</Style>
<Style TargetType="{x:Type toolkit:SelectableTextBlock}">
<Setter Property="FontSize" Value="18" />
<Setter Property="VerticalAlignment" Value="Center" />
</Style>
</StackPanel.Resources>
<Image Width="40" Height="42"
HorizontalAlignment="Right"
RenderOptions.BitmapScalingMode="LowQuality"
RenderOptions.CachingHint="Cache"
SnapsToDevicePixels="False"
Source="{Binding DialogType, Converter={StaticResource AlterDialogWindow_IconConverter}}"
Stretch="UniformToFill" />
<ScrollViewer MaxWidth="280" HorizontalScrollBarVisibility="Disabled" VerticalScrollBarVisibility="Auto">
<toolkit:SelectableTextBlock Margin="0,0,0,0"
HorizontalAlignment="Left" FontSize="18"
Foreground="#333333"
Text="{Binding Content}"
TextWrapping="Wrap" />
</ScrollViewer>
</StackPanel>
</DataTemplate>
<DataTemplate x:Key="TemplateFull">
<Grid Margin="40,10,40,0" HorizontalAlignment="Center" VerticalAlignment="Top">
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition />
</Grid.RowDefinitions>
<Image Width="54" Height="56"
HorizontalAlignment="Center"
RenderOptions.BitmapScalingMode="LowQuality"
RenderOptions.CachingHint="Cache"
SnapsToDevicePixels="False"
Source="{Binding DialogType, Converter={StaticResource AlterDialogWindow_IconConverter}}"
Stretch="UniformToFill" />
<ScrollViewer Grid.Row="1" MaxWidth="300"
Margin="0,12,0,0"
HorizontalScrollBarVisibility="Disabled"
VerticalScrollBarVisibility="Auto">
<StackPanel>
<toolkit:SelectableTextBlock Margin="0,0,0,0"
HorizontalAlignment="Center"
FontSize="18" Foreground="#333333"
Text="{Binding Content}"
TextWrapping="Wrap" />
<toolkit:SelectableTextBlock HorizontalAlignment="Center" FontSize="14" Foreground="#999999" Text="{Binding SubContent}" />
</StackPanel>
</ScrollViewer>
</Grid>
</DataTemplate>
交互區(qū)域可定義兩個(gè)模板：僅顯示確定按鈕，顯示確定和取消按鈕。
<DataTemplate x:Key="Template0">
<StackPanel Orientation="Horizontal">
<toolkit:ImageButton Width="108" Height="56"
Command="{Binding YesCommand}"
DownImage="{Binding DialogType, Converter={StaticResource AlterDialogWindow_ButtonConverter}, ConverterParameter='0|2'}"
Foreground="{Binding DialogType, Converter={StaticResource AlterDialogWindow_ButtonConverter}, ConverterParameter='0|3'}"
HoverImage="{Binding DialogType, Converter={StaticResource AlterDialogWindow_ButtonConverter}, ConverterParameter='0|1'}"
NormalImage="{Binding DialogType, Converter={StaticResource AlterDialogWindow_ButtonConverter}, ConverterParameter='0|0'}">
<Grid>
<TextBlock FontSize="16" Foreground="White" Text="{Binding YesButtonText}" Visibility="{Binding IsCountdown, Converter={StaticResource VisibilityConverter}, ConverterParameter='!'}" />
<StackPanel Orientation="Horizontal" TextBlock.Foreground="White" Visibility="{Binding IsCountdown, Converter={StaticResource VisibilityConverter}}">
<TextBlock FontSize="16" Text="{Binding YesButtonText}" />
<TextBlock FontSize="14" Text="{Binding Countdown, StringFormat={}({0}s)}" />
</StackPanel>
</Grid>
</toolkit:ImageButton>
<toolkit:ImageButton Width="108" Height="32"
Margin="29,0,0,0"
Command="{Binding NoCommand}"
DownImage="{Binding DialogType, Converter={StaticResource AlterDialogWindow_ButtonConverter}, ConverterParameter='1|2'}"
Foreground="#366d85"
HoverImage="{Binding DialogType, Converter={StaticResource AlterDialogWindow_ButtonConverter}, ConverterParameter='1|1'}"
IsDefault="True"
NormalImage="{Binding DialogType, Converter={StaticResource AlterDialogWindow_ButtonConverter}, ConverterParameter='1|0'}">
<TextBlock FontSize="16" Foreground="#0099ff" Text="{Binding NoButtonText}" />
</toolkit:ImageButton>
</StackPanel>
</DataTemplate>
<DataTemplate x:Key="Template1">
<StackPanel Orientation="Horizontal">
<toolkit:ImageButton Width="108" Height="56"
Command="{Binding YesCommand}"
DownImage="{Binding DialogType, Converter={StaticResource AlterDialogWindow_ButtonConverter}, ConverterParameter='0|2'}"
FontSize="18"
Foreground="{Binding DialogType, Converter={StaticResource AlterDialogWindow_ButtonConverter}, ConverterParameter='0|3'}"
HoverImage="{Binding DialogType, Converter={StaticResource AlterDialogWindow_ButtonConverter}, ConverterParameter='0|1'}"
IsDefault="True"
NormalImage="{Binding DialogType, Converter={StaticResource AlterDialogWindow_ButtonConverter}, ConverterParameter='0|0'}">
<Grid>
<TextBlock FontSize="16" Foreground="White" Text="{Binding YesButtonText}" Visibility="{Binding IsCountdown, Converter={StaticResource VisibilityConverter}, ConverterParameter='!'}" />
<StackPanel Orientation="Horizontal" TextBlock.Foreground="White" Visibility="{Binding IsCountdown, Converter={StaticResource VisibilityConverter}}">
<TextBlock FontSize="16" Text="{Binding YesButtonText}" />
<TextBlock FontSize="14" Text="{Binding Countdown, StringFormat={}({0}s)}" />
</StackPanel>
</Grid>
</toolkit:ImageButton>
</StackPanel>
</DataTemplate>
定義好了信息區(qū)域和交互區(qū)域的幾種模板后，AlterDialogWindow聲明兩個(gè)ContentPresenter表示信息區(qū)域和交互區(qū)域，通過模板選擇器選擇相應(yīng)模板。其中交互區(qū)域通過綁定對(duì)話框類型來判斷是否顯示該區(qū)域。
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="auto" />
</Grid.RowDefinitions>
<ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Top" Content="{Binding}">
<ContentPresenter.ContentTemplateSelector>
<local:AlterDialogWindowContentTemplateSelector Template0="{StaticResource TemplateMini}" Template1="{StaticResource TemplateNormal}" Template2="{StaticResource TemplateFull}" />
</ContentPresenter.ContentTemplateSelector>
</ContentPresenter>
<ContentPresenter Grid.Row="1" Margin="0,0,0,16"
HorizontalAlignment="center"
VerticalAlignment="Top"
Content="{Binding}"
Visibility="{Binding DialogMode, Converter={helper:EnumExcludeConverter}, ConverterParameter='Mini'}">
<ContentPresenter.ContentTemplateSelector>
<local:AlterDialogWindowButtonDataTemplateSelector Template0="{StaticResource Template0}" Template1="{StaticResource Template1}" />
</ContentPresenter.ContentTemplateSelector>
</ContentPresenter>
</Grid>
至此，一個(gè)消息對(duì)話框就基本完成了。前邊確定功能時(shí)提到調(diào)用消息對(duì)話框的窗口顯示遮罩層。針對(duì)這個(gè)功能，我們可以在AlterDialogWindow中定義一個(gè)ShowDialog方法，參數(shù)是調(diào)用消息對(duì)話框的窗口對(duì)象，然后在該窗口中加上一個(gè)半透明的Grid作為遮罩層，并在AlterDialogWindow的OnClosed事件處理邏輯中刪除遮罩層。
public bool? ShowDialog(DependencyObject parent)
{
if (this.Parent == null && parent != null)
{
Grid layer = new Grid() { Name = "maskLayer", Background = new SolidColorBrush(Color.FromArgb(128, 0, 0, 0)) };
_grid = Window.GetWindow(parent).FindFirstVisualChild<Grid>();
if (_grid.FindAllVisualChilds<Grid>().FirstOrDefault(r => r.Name == "maskLayer") == null)
_grid.Children.Add(layer);
if (_grid.RowDefinitions.Count > 0)
Grid.SetRowSpan(layer, _grid.RowDefinitions.Count);
if (_grid.ColumnDefinitions.Count > 0)
Grid.SetColumnSpan(layer, _grid.ColumnDefinitions.Count);
this.Owner = Window.GetWindow(parent);
this.WindowStartupLocation = WindowStartupLocation.CenterOwner;
}
return ShowDialog();
}
小結(jié)
本文介紹了自定義消息對(duì)話框的主要思路和代碼，通過造輪子，重新溫習(xí)了樣式、主題、控件模板、數(shù)據(jù)模板、模板選擇器、觸發(fā)器、值轉(zhuǎn)換器等技術(shù)。這也是MaterialDesign、HandyControl等控件珠玉在前，還要自己造輪子的原因之一。文章來源：http://www.zghlxwxcb.cn/news/detail-747173.html
代碼示例
https://github.com/czwy/AlertDialogWindow文章來源地址http://www.zghlxwxcb.cn/news/detail-747173.html
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