maui-linux/Xamarin.Forms.Platform.WPF/Themes/FormsContentDialog.xaml

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:System="clr-namespace:System;assembly=mscorlib"
                    xmlns:controls="clr-namespace:Xamarin.Forms.Platform.WPF.Controls">

    <ResourceDictionary.MergedDictionaries>
        <ResourceDictionary Source="/Xamarin.Forms.Platform.WPF;component/Assets/Converters.xaml" />
    </ResourceDictionary.MergedDictionaries>

    <DataTemplate x:Key="TitleDefaultTemplate" >
        <TextBlock DataContext="{Binding}" 
                   Text="{Binding}"
                   FontFamily="Segoe UI"
                   FontSize="26"
                   TextOptions.TextFormattingMode="Ideal"
                   TextWrapping="WrapWithOverflow"
                   Foreground="Black"/>
    </DataTemplate>

    <Style TargetType="controls:FormsContentDialog">
        <Setter Property="IsTabStop" Value="False" />
        <Setter Property="Width" Value="500" />
        <Setter Property="Height" Value="Auto" />
        <Setter Property="TitleTemplate" Value="{StaticResource TitleDefaultTemplate}" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="controls:FormsContentDialog">
                    <Border BorderBrush="{DynamicResource AccentColor}" Background="#FFF2F2F2" BorderThickness="2">

                        <Grid Margin="24">
                            <Grid.RowDefinitions>
                                <RowDefinition Height="Auto" />
                                <RowDefinition Height="*" MinHeight="150" />
                                <RowDefinition Height="Auto" />
                            </Grid.RowDefinitions>

                            <!-- title -->
                            <ContentControl x:Name="Title"
                                        Content="{TemplateBinding Title}"
                                        ContentTemplate="{TemplateBinding TitleTemplate}"
                                        IsTabStop="False">
                            </ContentControl>

                            <!-- content -->
                            <ContentPresenter x:Name="Content" Margin="0,20" 
                                    Content="{TemplateBinding Content}"
                                    ContentTemplate="{TemplateBinding ContentTemplate}"
                                    Grid.Row="1" >
                                <ContentPresenter.Resources>
                                    <DataTemplate DataType="{x:Type System:String}" >
                                        <TextBlock Text="{Binding}"
                                                       FontFamily="Segoe UI"
                                                       FontSize="16"
                                                       TextOptions.TextFormattingMode="Ideal"
                                                       TextTrimming="CharacterEllipsis" 
                                                       Foreground="Black"/>
                                    </DataTemplate>
                                </ContentPresenter.Resources>
                            </ContentPresenter>

                            <!-- buttons -->
                            <StackPanel Grid.Row="2" Orientation="Horizontal" HorizontalAlignment="Right">
                                <Button x:Name="PART_PrimaryButton" Content="{TemplateBinding PrimaryButtonText}" 
                                            Height="50"
                                            MinWidth="140"
                                            Margin="4,0,0,0" 
                                            BorderBrush="Transparent" 
                                            Command="{x:Static controls:FormsContentDialog.PrimaryButtonRoutedCommand}">
                                </Button>
                                <Button x:Name="PART_SecondaryButton" Content="{TemplateBinding SecondaryButtonText}"  
                                            Height="50"
                                            MinWidth="140"
                                            Margin="4,0,0,0" 
                                            BorderBrush="Transparent" 
                                            Command="{x:Static controls:FormsContentDialog.SecondaryButtonRoutedCommand}"/>
                            </StackPanel>
                        </Grid>
                    </Border>

                    <ControlTemplate.Triggers>
                        <Trigger Property="IsPrimaryButtonEnabled" Value="false">
                            <Setter TargetName="PART_PrimaryButton" Property="Visibility" Value="Collapsed" />
                        </Trigger>
                        <Trigger Property="PrimaryButtonText" Value="{x:Static System:String.Empty}">
                            <Setter TargetName="PART_PrimaryButton" Property="Visibility" Value="Collapsed" />
                        </Trigger>
                        <Trigger Property="PrimaryButtonText" Value="{x:Null}">
                            <Setter TargetName="PART_PrimaryButton" Property="Visibility" Value="Collapsed" />
                        </Trigger>

                        <Trigger Property="IsSecondaryButtonEnabled" Value="false">
                            <Setter TargetName="PART_SecondaryButton" Property="Visibility" Value="Collapsed" />
                        </Trigger>
                        <Trigger Property="SecondaryButtonText" Value="{x:Static System:String.Empty}">
                            <Setter TargetName="PART_SecondaryButton" Property="Visibility" Value="Collapsed" />
                        </Trigger>
                        <Trigger Property="SecondaryButtonText" Value="{x:Null}">
                            <Setter TargetName="PART_SecondaryButton" Property="Visibility" Value="Collapsed" />
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>