Prism.Avalonia - MessageDialogView

MessageDialogView.axaml

<UserControl xmlns="https://github.com/avaloniaui"
             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"
             MaxHeight="{Binding MaxHeight}"
             MaxWidth="{Binding MaxWidth}"
             mc:Ignorable="d" d:DesignWidth="500" d:DesignHeight="150"
             x:Class="SampleApp.Views.MessageDialogView">
  <UserControl.Styles>
    <Style Selector="TextBox">
      <Setter Property="BorderThickness" Value="0" />
      <Setter Property="Background" Value="Transparent" />
      <Setter Property="Margin" Value="15" />
      <Setter Property="TextWrapping" Value="Wrap" />
      <Setter Property="AcceptsReturn" Value="True" />
      <Setter Property="IsReadOnly" Value="True" />
      <Setter Property="CaretBrush" Value="Transparent" />
      <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto" />
      <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Disabled" />
    </Style>
    <Style Selector="TextBox:pointerover /template/ Border#border">
      <Setter Property="Background" Value="Transparent" />
    </Style>
    <Style Selector="TextBox:pointerover /template/ Border#PART_BorderElement">
      <Setter Property="Background" Value="Transparent" />
    </Style>
    <Style Selector="TextBox:focus /template/ Border#border">
      <Setter Property="BorderThickness" Value="0" />
      <Setter Property="Background" Value="Transparent" />
    </Style>
    <Style Selector="TextBox:focus /template/ Border#PART_BorderElement">
      <Setter Property="BorderThickness" Value="0" />
      <Setter Property="Background" Value="Transparent" />
    </Style>
    <Style Selector="TextBox.header">
      <Setter Property="FontWeight" Value="Bold" />
      <Setter Property="Margin" Value="0,0,0,10" />
    </Style>
    <Style Selector="Button">
      <Setter Property="HorizontalContentAlignment" Value="Center" />
      <Setter Property="Margin" Value="15" />
      <Setter Property="MinHeight" Value="24" />
      <Setter Property="MinWidth" Value="75" />
    </Style>
  </UserControl.Styles>
  <Grid ColumnDefinitions="Auto,*" RowDefinitions="*,15,Auto">

    <TextBox Grid.Row="0"
             Grid.Column="1"
             Text="{Binding CustomMessage}" />

    <!-- ButtonResult 1=OK -->
    <Button Content="OK"
            Command="{Binding CmdResult}"
            CommandParameter="1"
            Grid.Column="0"
            Grid.ColumnSpan="2"
            Grid.Row="2"
            HorizontalAlignment="Right"/>
  </Grid>

  <!--
    <Button Content="None" Command="{Binding CmdResult}" CommandParameter="0" />
    <Button Content="OK" Command="{Binding CmdResult}" CommandParameter="1" />
    <Button Content="Cancel" Command="{Binding CmdResult}" CommandParameter="2" />
    <Button Content="Abort" Command="{Binding CmdResult}" CommandParameter="3" />
    <Button Content="Retry" Command="{Binding CmdResult}" CommandParameter="4" />
    <Button Content="Ignore" Command="{Binding CmdResult}" CommandParameter="5" />
    <Button Content="Yes" Command="{Binding CmdResult}" CommandParameter="6" />
    <Button Content="No" Command="{Binding CmdResult}" CommandParameter="7" />
  -->
</UserControl>

MessageDialogViewModel.cs

using System;
using Prism.Commands;
using Prism.Mvvm;
using Prism.Services.Dialogs;

namespace SampleApp.ViewModels;

public class MessageDialogViewModel : BindableBase, IDialogAware
{
    private string _customMessage = string.Empty;
    private string _title = "Notification";
    private int _maxHeight;
    private int _maxWidth;

    public MessageDialogViewModel()
    {
        // Since this is a basic ShellWindow, there's nothing
        // to do here.
        // For enterprise apps, you could register up subscriptions
        // or other startup background tasks so that they get triggered
        // on startup, rather than putting them in the DashboardViewModel.
        //
        // For example, initiate the pulling of News Feeds, etc.
        Title = "Alert!";

        MaxHeight = 800;
        MaxWidth = 600;
    }

    public event Action<IDialogResult>? RequestClose;

    public string Title
    {
        get => _title;
        set => SetProperty(ref _title, value);
    }

    public int MaxHeight
    {
        get => _maxHeight;
        set => SetProperty(ref _maxHeight, value);
    }

    public int MaxWidth
    {
        get => _maxWidth;
        set => SetProperty(ref _maxWidth, value);
    }

    public DelegateCommand<string> CmdResult => new DelegateCommand<string>((param) =>
    {
        // None = 0
        // OK = 1
        // Cancel = 2
        // Abort = 3
        // Retry = 4
        // Ignore = 5
        // Yes = 6
        // No = 7
        ButtonResult result = ButtonResult.None;

        if (int.TryParse(param, out int intResult))
            result = (ButtonResult)intResult;

        RaiseRequestClose(new DialogResult(result));
    });

    public string CustomMessage
    {
        get => _customMessage;
        set => SetProperty(ref _customMessage, value);
    }

    public virtual bool CanCloseDialog()
    {
        // Allow the dialog to close
        return true;
    }

    public virtual void OnDialogClosed()
    {
        // Detatch custom eventhandlers here, etc.
    }

    public void OnDialogOpened(IDialogParameters parameters)
    {
        var title = parameters.GetValue<string>("title");
        if (!string.IsNullOrEmpty(title))
            Title = title;

        CustomMessage = parameters.GetValue<string>("message");
    }

    public virtual void RaiseRequestClose(IDialogResult dialogResult)
    {
        RequestClose?.Invoke(dialogResult);
    }
}