tôi cảm thấy tôi chỉ tìm thấy một khá tốt đẹp Giải pháp MVVM cho vấn đề này. Tôi đã viết một hành vi phơi bày thuộc tính loại WindowType và thuộc tính boolean Open. DataBinding thứ hai cho phép ViewModel mở và đóng các cửa sổ một cách dễ dàng, mà không biết gì về View.
Gotta yêu hành vi ...:)
XAML:
<UserControl x:Class="WpfApplication1.OpenCloseWindowDemo"
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:WpfApplication1"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<UserControl.DataContext>
<local:ViewModel />
</UserControl.DataContext>
<i:Interaction.Behaviors>
<!-- TwoWay binding is necessary, otherwise after user closed a window directly, it cannot be opened again -->
<local:OpenCloseWindowBehavior WindowType="local:BlackWindow" Open="{Binding BlackOpen, Mode=TwoWay}" />
<local:OpenCloseWindowBehavior WindowType="local:YellowWindow" Open="{Binding YellowOpen, Mode=TwoWay}" />
<local:OpenCloseWindowBehavior WindowType="local:PurpleWindow" Open="{Binding PurpleOpen, Mode=TwoWay}" />
</i:Interaction.Behaviors>
<UserControl.Resources>
<Thickness x:Key="StdMargin">5</Thickness>
<Style TargetType="Button" >
<Setter Property="MinWidth" Value="60" />
<Setter Property="Margin" Value="{StaticResource StdMargin}" />
</Style>
<Style TargetType="Border" >
<Setter Property="Margin" Value="{StaticResource StdMargin}" />
</Style>
</UserControl.Resources>
<Grid>
<StackPanel>
<StackPanel Orientation="Horizontal">
<Border Background="Black" Width="30" />
<Button Content="Open" Command="{Binding OpenBlackCommand}" CommandParameter="True" />
<Button Content="Close" Command="{Binding OpenBlackCommand}" CommandParameter="False" />
</StackPanel>
<StackPanel Orientation="Horizontal">
<Border Background="Yellow" Width="30" />
<Button Content="Open" Command="{Binding OpenYellowCommand}" CommandParameter="True" />
<Button Content="Close" Command="{Binding OpenYellowCommand}" CommandParameter="False" />
</StackPanel>
<StackPanel Orientation="Horizontal">
<Border Background="Purple" Width="30" />
<Button Content="Open" Command="{Binding OpenPurpleCommand}" CommandParameter="True" />
<Button Content="Close" Command="{Binding OpenPurpleCommand}" CommandParameter="False" />
</StackPanel>
</StackPanel>
</Grid>
</UserControl>
YellowWindow (Black/Tím như nhau):
<Window x:Class="WpfApplication1.YellowWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="YellowWindow" Height="300" Width="300">
<Grid Background="Yellow" />
</Window>
ViewModel, ActionCommand:
using System;
using System.ComponentModel;
using System.Windows.Input;
namespace WpfApplication1
{
public class ViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
if (this.PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
private bool _blackOpen;
public bool BlackOpen { get { return _blackOpen; } set { _blackOpen = value; OnPropertyChanged("BlackOpen"); } }
private bool _yellowOpen;
public bool YellowOpen { get { return _yellowOpen; } set { _yellowOpen = value; OnPropertyChanged("YellowOpen"); } }
private bool _purpleOpen;
public bool PurpleOpen { get { return _purpleOpen; } set { _purpleOpen = value; OnPropertyChanged("PurpleOpen"); } }
public ICommand OpenBlackCommand { get; private set; }
public ICommand OpenYellowCommand { get; private set; }
public ICommand OpenPurpleCommand { get; private set; }
public ViewModel()
{
this.OpenBlackCommand = new ActionCommand<bool>(OpenBlack);
this.OpenYellowCommand = new ActionCommand<bool>(OpenYellow);
this.OpenPurpleCommand = new ActionCommand<bool>(OpenPurple);
}
private void OpenBlack(bool open) { this.BlackOpen = open; }
private void OpenYellow(bool open) { this.YellowOpen = open; }
private void OpenPurple(bool open) { this.PurpleOpen = open; }
}
public class ActionCommand<T> : ICommand
{
public event EventHandler CanExecuteChanged;
private Action<T> _action;
public ActionCommand(Action<T> action)
{
_action = action;
}
public bool CanExecute(object parameter) { return true; }
public void Execute(object parameter)
{
if (_action != null)
{
var castParameter = (T)Convert.ChangeType(parameter, typeof(T));
_action(castParameter);
}
}
}
}
Mở CloseWindowBehavior:
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Interactivity;
namespace WpfApplication1
{
public class OpenCloseWindowBehavior : Behavior<UserControl>
{
private Window _windowInstance;
public Type WindowType { get { return (Type)GetValue(WindowTypeProperty); } set { SetValue(WindowTypeProperty, value); } }
public static readonly DependencyProperty WindowTypeProperty = DependencyProperty.Register("WindowType", typeof(Type), typeof(OpenCloseWindowBehavior), new PropertyMetadata(null));
public bool Open { get { return (bool)GetValue(OpenProperty); } set { SetValue(OpenProperty, value); } }
public static readonly DependencyProperty OpenProperty = DependencyProperty.Register("Open", typeof(bool), typeof(OpenCloseWindowBehavior), new PropertyMetadata(false, OnOpenChanged));
/// <summary>
/// Opens or closes a window of type 'WindowType'.
/// </summary>
private static void OnOpenChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var me = (OpenCloseWindowBehavior)d;
if ((bool)e.NewValue)
{
object instance = Activator.CreateInstance(me.WindowType);
if (instance is Window)
{
Window window = (Window)instance;
window.Closing += (s, ev) =>
{
if (me.Open) // window closed directly by user
{
me._windowInstance = null; // prevents repeated Close call
me.Open = false; // set to false, so next time Open is set to true, OnOpenChanged is triggered again
}
};
window.Show();
me._windowInstance = window;
}
else
{
// could check this already in PropertyChangedCallback of WindowType - but doesn't matter until someone actually tries to open it.
throw new ArgumentException(string.Format("Type '{0}' does not derive from System.Windows.Window.", me.WindowType));
}
}
else
{
if (me._windowInstance != null)
me._windowInstance.Close(); // closed by viewmodel
}
}
}
}
Bạn cũng có thể đặt DataContext của UserControl thành ViewModel, loại bỏ thuộc tính công khai ViewModel. Điều này sẽ yêu cầu một số đúc trên đăng ký sự kiện nhưng là một thực hành tốt kể từ trong MVVM bạn cần phải thiết lập UserControl.DataContext để ViewModel anyways. Ngoài ra, hãy chắc chắn để thực hiện một số xác nhận rằng ChildWindowsCloseRequested của bạn không phải là null trước khi gọi nó, hoặc bạn sẽ nhận được một ngoại lệ. –
True, tôi sẽ cập nhật câu trả lời của tôi, cổ vũ. –