.NET Core 3 WPF MVVM框架 Prism系列之对话框服务

 本文将介绍如何在.NET Core3环境下使用MVVM框架Prism的对话框服务,这也是prism系列的最后一篇完结文章,下面是Prism系列文章的索引:
.NET Core 3 WPF MVVM框架 Prism系列之文章索引

一.对话框服务

在Prism中,通过一个IDialogAware接口来实现对话框服务:

public interface IDialogAware
{
    bool CanCloseDialog();
    void OnDialogClosed();
    void OnDialogOpened(IDialogParameters parameters);
    string Title { get; set; }
    event Action<IDialogResult> RequestClose;
}
  • CanCloseDialog()函数是决定窗体是否关闭
  • OnDialogClosed()函数是窗体关闭时触发,触发条件取决于CanCloseDialog()函数
  • OnDialogOpened()函数时窗体打开时触发,比窗体Loaded事件早触发
  • Title为窗体的标题
  • RequestClose为关闭事件,可由此控制窗体的关闭

1.创建对话框的View和ViewModel

AlertDialog.xaml:

<UserControl x:Class="PrismMetroSample.Shell.Views.Dialogs.AlertDialog"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:PrismMetroSample.Shell.Views.Dialogs"
             mc:Ignorable="d"  
             xmlns:prism="http://prismlibrary.com/"
             Width="350" Height="120" prism:ViewModelLocator.AutoWireViewModel="True">
    <Grid  Margin="5">
        <Grid.RowDefinitions>
            <RowDefinition />
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>
        <Grid Margin="0,0,0,10">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="70"/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
            <Image Source="pack://application:,,,/PrismMetroSample.Infrastructure;Component/Assets/Photos/alter.png" Height="40" UseLayoutRounding="True" RenderOptions.BitmapScalingMode="HighQuality"/>
            <TextBlock  Grid.Column="1" Text="{Binding Message}" HorizontalAlignment="Left" VerticalAlignment="Center" Grid.Row="0" TextWrapping="Wrap"  FontSize="15" FontFamily="Open Sans"/>
        </Grid>
        <Grid Grid.Row="1">
            <Grid.ColumnDefinitions>
                <ColumnDefinition/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
            <Button Margin="5"  Foreground="White"  FontSize="12" Background="#5cb85c" Command="{Binding CloseDialogCommand}" CommandParameter="true" Content="Yes" Width="64" Height="28" HorizontalAlignment="Right" Grid.Row="1"/>
            <Button Grid.Column="1" Margin="5"  Foreground="White"  FontSize="12" Background="#d9534f" Command="{Binding CloseDialogCommand}" CommandParameter="false" Content="No" Width="64" Height="28" HorizontalAlignment="Left" Grid.Row="1"/>
        </Grid>
       
    </Grid>
</UserControl>

AlertDialogViewModel.cs:

public class AlertDialogViewModel : BindableBase, IDialogAware
{
    private DelegateCommand<string> _closeDialogCommand;
    public DelegateCommand<string> CloseDialogCommand =>
        _closeDialogCommand ?? (_closeDialogCommand = new DelegateCommand<string>(ExecuteCloseDialogCommand));

    void ExecuteCloseDialogCommand(string parameter)
    {
        ButtonResult result = ButtonResult.None;
        if (parameter?.ToLower() == "true")
            result = ButtonResult.Yes;
        else if (parameter?.ToLower() == "false")
            result = ButtonResult.No;
         RaiseRequestClose(new DialogResult(result));
     }

     //触发窗体关闭事件
     public virtual void RaiseRequestClose(IDialogResult dialogResult)
     {
         RequestClose?.Invoke(dialogResult);
     }

     private string _message;
     public string Message
     {
         get { return _message; }
         set { SetProperty(ref _message, value); }
     }

     private string _title = "Notification";
     public string Title
     {
         get { return _title; }
         set { SetProperty(ref _title, value); }
     }

     public event Action<IDialogResult> RequestClose;

     public bool CanCloseDialog()
     {
         return true;
     }

     public void OnDialogClosed()
     {
            
     }

     public void OnDialogOpened(IDialogParameters parameters)
     {
         Message = parameters.GetValue<string>("message");
     }
 }

2.注册对话框

App.cs:

protected override void RegisterTypes(IContainerRegistry containerRegistry)
{
     containerRegistry.RegisterDialog<AlertDialog, AlertDialogViewModel>();
}

还可以注册时起名字:

containerRegistry.RegisterDialog<AlertDialog, AlertDialogViewModel>(“alertDialog”);

3.使用对话框服务

CreateAccountViewModel.cs(修改部分):

public CreateAccountViewModel(IRegionManager regionManager, IDialogService dialogService)
{
     _regionManager = regionManager;
     _dialogService = dialogService;
}

 public void ConfirmNavigationRequest(NavigationContext navigationContext, Action<bool> continuationCallback)
 {
     if (!string.IsNullOrEmpty(RegisteredLoginId) && this.IsUseRequest)
     {
          _dialogService.ShowDialog("AlertDialog", new DialogParameters($"message={"是否需要用当前注册的用户登录?"}"), r =>
           {
                 if (r.Result == ButtonResult.Yes)
                     navigationContext.Parameters.Add("loginId", RegisteredLoginId);
           });
      }
      continuationCallback(true);

 }

效果如下:

我们是通过调用IDialogService接口的ShowDialog函数来调用,下面是该接口的定义:

public interface IDialogService : Object
{
    Void Show(String name, IDialogParameters parameters, Action<IDialogResult> callback);
    Void ShowDialog(String name, IDialogParameters parameters, Action<IDialogResult> callback);
    
 }

我们可以发现show和ShowDialog函数都是一样形参,无非就是使用场景不一样

  • name:所要调用对话框view的名字,当注册别名时,只能使用别名来调用
  • parameters:IDialogParameters接口类型参数,传入的提示消息,通常是$"message={xxxx}"格式,然后再ViewModel的OnDialogOpened函数通过IDialogParameters接口的GetValue函数来获取
  • callback:用于传入无返回值回调函数

二.自定义对话框窗体

 我们在上述可以看到,对话框的窗体时一个WPF自带的窗体,但是当我们要用自己自定义窗体,例如,去掉window的Icon,保留最大化,最小化和关闭,或者使用一些第三方的窗体控件,prism支持通过注册一个对话框窗体,然后通过再不同对话框的View指定其对话框窗体的style,则可以很灵活的实现不一样的对话框,下面让我们来看看如何操作:

1.注册自定义对话框窗体

新建一个窗体,DialogWindow.xaml:

<Window x:Class="PrismMetroSample.Shell.Views.Dialogs.DialogWindow"
        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:PrismMetroSample.Shell.Views.Dialogs"
        mc:Ignorable="d"  
        xmlns:prism="http://prismlibrary.com/"
         >
    <Grid>
        
    </Grid>
</Window>

DialogWindow.xaml.cs:

public partial class DialogWindow : Window, IDialogWindow
{
    public DialogWindow()
    {
        InitializeComponent();
    }

    protected override void OnSourceInitialized(EventArgs e)
    {
        WindowHelp.RemoveIcon(this);//使用win32函数去除Window的Icon部分
    }

    public IDialogResult Result { get; set; }
}

App.cs:

protected override void RegisterTypes(IContainerRegistry containerRegistry)
{
     containerRegistry.RegisterDialogWindow<DialogWindow>();//注册自定义对话框窗体
}

2.自定义对话框窗体Style

AlertDialog.xaml:

 <prism:Dialog.WindowStyle>
     <Style TargetType="Window">
          <Setter Property="prism:Dialog.WindowStartupLocation" Value="CenterScreen" />
          <Setter Property="ShowInTaskbar" Value="False"/>
          <Setter Property="SizeToContent" Value="WidthAndHeight"/>
     </Style>
 </prism:Dialog.WindowStyle>

效果如下:

如何我们要将窗体样式全部去掉,改动AlertDialog.xaml:

 <prism:Dialog.WindowStyle>
     <Style TargetType="Window">
          <Setter Property="prism:Dialog.WindowStartupLocation" Value="CenterScreen" />
          <Setter Property="ShowInTaskbar" Value="False"/>
          <Setter Property="SizeToContent" Value="WidthAndHeight"/>
          <Setter Property="WindowStyle" Value="None"/>
     </Style>
 </prism:Dialog.WindowStyle>

那么就变成了下面这样:

最终,我们的最后效果为这样:

三.小结

 通过Prism的对话框服务,我们可以很好的通过一个IDialogService接口来统一管理对话框的弹出逻辑,而且可以使用依赖注入的模式,如果换成之前要定义一些自定义的对话框,那么也要强依赖View部分,而且可以通过自定义不同对话框的窗体样式,达到一定的灵活性(例如最终效果演示,用了两个不同的对话框样式),至此, .NET Core3.x Prism系列文章已经全部写完

四.源码

 最后,附上整个demo的源代码:PrismDemo源码

posted @ 2020-04-26 09:05  RyzenAdorer  阅读(1934)  评论(12编辑  收藏