也许下面的代码会有所帮助:

using Windows.UI.Popups;
namespace something.MyViewModels
{
    public class TestViewModel
    {
        public void aRandonMethode()
        {
            MyMessageBox("aRandomMessage");
        }

        public async void MyMessageBox(string mytext)
        {
            var dialog = new MessageDialog(mytext);
            await dialog.ShowAsync();
        }
    }
}

WPF中与WinForms的MessageBox等价的是System.Windows.MessageBox。

WPF扩展工具包中的MessageBox非常好。它在Microsoft.Windows.Controls.MessageBox中，在引用工具箱DLL之后。当然，这是2011年8月9日发布的，所以它本来就不是你的选择。每个人都可以在Github上找到它。

如果你想拥有自己漂亮的wpf消息框: 创建新的Wpf窗口

下面是xaml:

<Window x:Class="popup.MessageboxNew"
        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:popup"
        mc:Ignorable="d"
        Title="" SizeToContent="WidthAndHeight" WindowStartupLocation="CenterScreen" WindowStyle="None" ResizeMode="NoResize" AllowsTransparency="True" Background="Transparent" Opacity="1"
        >
    <Window.Resources>

    </Window.Resources>
    <Border x:Name="MainBorder" Margin="10" CornerRadius="8" BorderThickness="0" BorderBrush="Black" Padding="0" >
        <Border.Effect>
            <DropShadowEffect x:Name="DSE" Color="Black" Direction="270" BlurRadius="20" ShadowDepth="3" Opacity="0.6" />
        </Border.Effect>
        <Border.Triggers>
            <EventTrigger RoutedEvent="Window.Loaded">
                <BeginStoryboard>
                    <Storyboard>
                        <DoubleAnimation Storyboard.TargetName="DSE" Storyboard.TargetProperty="ShadowDepth" From="0" To="3" Duration="0:0:1" AutoReverse="False" />
                        <DoubleAnimation Storyboard.TargetName="DSE" Storyboard.TargetProperty="BlurRadius" From="0" To="20" Duration="0:0:1" AutoReverse="False" />
                    </Storyboard>
                </BeginStoryboard>
            </EventTrigger>
        </Border.Triggers>
        <Grid Loaded="FrameworkElement_OnLoaded">
            <Grid.RowDefinitions>
                <RowDefinition Height="Auto"/>
            </Grid.RowDefinitions>
            <Border Name="Mask" CornerRadius="8" Background="White" />
            <Grid x:Name="Grid" Background="White">
                <Grid.OpacityMask>
                    <VisualBrush Visual="{Binding ElementName=Mask}"/>
                </Grid.OpacityMask>
                <StackPanel Name="StackPanel" >
                    <TextBox Style="{DynamicResource MaterialDesignTextBox}" Name="TitleBar" IsReadOnly="True" IsHitTestVisible="False" Padding="10" FontFamily="Segui" FontSize="14" 
                             Foreground="Black" FontWeight="Normal"
                             Background="Yellow" HorizontalAlignment="Stretch" VerticalAlignment="Center" Width="Auto" HorizontalContentAlignment="Center" BorderThickness="0"/>
                    <DockPanel Name="ContentHost" Margin="0,10,0,10" >
                        <TextBlock Margin="10" Name="Textbar"></TextBlock>
                    </DockPanel>
                    <DockPanel Name="ButtonHost" LastChildFill="False" HorizontalAlignment="Center" >
                        <Button Margin="10" Click="ButtonBase_OnClick" Width="70">Yes</Button>
                        <Button Name="noBtn" Margin="10" Click="cancel_Click" Width="70">No</Button>
                    </DockPanel>
                </StackPanel>
            </Grid>
        </Grid>
    </Border>
</Window>

对于这个文件的cs:

public partial class MessageboxNew : Window
    {
        public MessageboxNew()
        {
            InitializeComponent();
            //second time show error solved
            if (Application.Current == null) new Application();
                    Application.Current.ShutdownMode = ShutdownMode.OnExplicitShutdown;
        }

        private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
        {
            DialogResult = true;
        }

        private void cancel_Click(object sender, RoutedEventArgs e)
        {
            DialogResult = false;
        }

        private void FrameworkElement_OnLoaded(object sender, RoutedEventArgs e)
        {
            this.MouseDown += delegate { DragMove(); };
        }
    }

然后创建一个类来使用它:

public class Mk_MessageBox
{
    public static bool? Show(string title, string text)
    {
        MessageboxNew msg = new MessageboxNew
        {
            TitleBar = {Text = title},
            Textbar = {Text = text}
        };
        msg.noBtn.Focus();
        return msg.ShowDialog();
    }
}

现在你可以像这样创建你的消息框:

var result = Mk_MessageBox.Show("Remove Alert", "This is gonna remove directory from host! Are you sure?");
            if (result == true)
            {
                // whatever
            }

把这个拷贝到App.xaml里面

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <!-- MahApps.Metro resource dictionaries. Make sure that all file names are Case Sensitive! -->
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Controls.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Fonts.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Colors.xaml" />
            <!-- Accent and AppTheme setting -->
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/Blue.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/BaseLight.xaml" />

            <!--two new guys-->
            <ResourceDictionary Source="pack://application:,,,/MaterialDesignColors;component/Themes/Recommended/Primary/MaterialDesignColor.LightBlue.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MaterialDesignColors;component/Themes/Recommended/Accent/MaterialDesignColor.Green.xaml" />

            <ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.Light.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.Defaults.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MaterialDesignColors;component/Themes/Recommended/Primary/MaterialDesignColor.DeepPurple.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MaterialDesignColors;component/Themes/Recommended/Accent/MaterialDesignColor.Lime.xaml" />
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Application.Resources>

-------------------------------

推荐人: https://www.red-gate.com/simple-talk/dotnet/net-development/using-c-to-create-powershell-cmdlets-the-basics/

对于逻辑，我如何制作自己的消息框

正如其他人所说，在WPF命名空间(System.Windows)中有一个MessageBox。

问题是，它是相同的旧消息框与确定，取消等。Windows Vista和Windows 7转而使用任务对话框。

不幸的是，任务对话框没有简单的标准界面。我使用来自CodeProject KB的实现。

也许下面的代码会有所帮助:

using Windows.UI.Popups;
namespace something.MyViewModels
{
    public class TestViewModel
    {
        public void aRandonMethode()
        {
            MyMessageBox("aRandomMessage");
        }

        public async void MyMessageBox(string mytext)
        {
            var dialog = new MessageDialog(mytext);
            await dialog.ShowAsync();
        }
    }
}