[英]Save and Close in Current Window in WPF-MVVM
我的窗口中有兩個按鈕,保存,保存和關閉。 如果用戶單擊“保存”,則可以成功保存詳細信息。 當用戶單擊“保存並關閉”時,我無法弄清楚如何關閉窗口。 這是我保存的代碼
<telerik:RadButton x:Name="button_Save" Content="Save" Command="{Binding SaveProductCommand}" CommandParameter="{Binding ElementName=ProductName, Path=Text}" />
這是我的中繼命令。
public ICommand SaveProductCommand
{
get
{
return new RelayCommand<string>(SaveProductExecute);
}
}
我的第一個問題:
我們可以為Save和Save&Close再傳遞一個參數True或false嗎? 這樣我們就只能對兩者使用一個中繼命令?
第二個問題:
保存后如何關閉當前窗口?
很好的問題..這里的關鍵是使用Action
。看看我的示例
我們將盡量減少編碼。
我們可以為Save和Save&Close再傳遞一個參數True或false嗎? 這樣我們就只能對兩者使用一個中繼命令?
由於您還沒有提到如何傳遞true或false,所以我包括了一個列表框,其中包含兩個字符串項True
和False
。
如果選擇true
則僅執行命令的一部分;如果選擇false
則將執行命令中的兩種方法。
使用按鈕和列表框創建視圖
<ListBox x:Name="items"> <System:String>True</System:String> <System:String>False</System:String> </ListBox> <Button Content="MyButton" Command="{Binding Path=MyCustomCommand}" CommandParameter="{Binding SelectedItem,ElementName=items}"/>
創建ViewModel即MyViewModel.cs
public class MyViewModel : INotifyPropertyChanged { public Action CloseAction { get; set; } public ICommand MyCustomCommand { get; set; } public MyViewModel() { MyCustomCommand = new RelayCommand(new Action<object>(MyFunction)); } private void MyFunction(object MyCommandParameter) { if (Convert.ToString(MyCommandParameter) == "True") { MessageBox.Show("Save Executed"); } else { MessageBox.Show("Save Execcuted"); CloseAction(); } }
在代碼背后
public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); MyViewModel mv = new MyViewModel(); this.DataContext = mv; if (mv.CloseAction == null) mv.CloseAction = new Action(() => this.Close()); } }
考慮利用帶參數的消息傳遞在對象之間傳遞數據。
您可以使用EventAggregator或MessageBus 。
想法是讓您的用戶控件訂閱他們想要響應的事件。
注意:
我用viewmodels做到這一點。 但是,我認為在將此代碼添加到旨在具有普遍用途的用戶控件時,這是一種代碼氣味,而與使用它們的應用程序無關。
我將“ 發布訂閱”模式用於復雜的類相關性:
視圖模型:
public class ViewModel : ViewModelBase
{
public ViewModel()
{
CloseComand = new DelegateCommand((obj) =>
{
MessageBus.Instance.Publish(Messages.REQUEST_DEPLOYMENT_SETTINGS_CLOSED, null);
});
}
}
窗口:
public partial class SomeWindow : Window
{
Subscription _subscription = new Subscription();
public SomeWindow()
{
InitializeComponent();
_subscription.Subscribe(Messages.REQUEST_DEPLOYMENT_SETTINGS_CLOSED, obj =>
{
this.Close();
});
}
}
您可以利用Bizmonger.Patterns獲取MessageBus。
MessageBus
public class MessageBus
{
#region Singleton
static MessageBus _messageBus = null;
private MessageBus() { }
public static MessageBus Instance
{
get
{
if (_messageBus == null)
{
_messageBus = new MessageBus();
}
return _messageBus;
}
}
#endregion
#region Members
List<Observer> _observers = new List<Observer>();
List<Observer> _oneTimeObservers = new List<Observer>();
List<Observer> _waitingSubscribers = new List<Observer>();
List<Observer> _waitingUnsubscribers = new List<Observer>();
int _publishingCount = 0;
#endregion
public void Subscribe(string message, Action<object> response)
{
Subscribe(message, response, _observers);
}
public void SubscribeFirstPublication(string message, Action<object> response)
{
Subscribe(message, response, _oneTimeObservers);
}
public int Unsubscribe(string message, Action<object> response)
{
var observers = new List<Observer>(_observers.Where(o => o.Respond == response).ToList());
observers.AddRange(_waitingSubscribers.Where(o => o.Respond == response));
observers.AddRange(_oneTimeObservers.Where(o => o.Respond == response));
if (_publishingCount == 0)
{
observers.ForEach(o => _observers.Remove(o));
}
else
{
_waitingUnsubscribers.AddRange(observers);
}
return observers.Count;
}
public int Unsubscribe(string subscription)
{
var observers = new List<Observer>(_observers.Where(o => o.Subscription == subscription).ToList());
observers.AddRange(_waitingSubscribers.Where(o => o.Subscription == subscription));
observers.AddRange(_oneTimeObservers.Where(o => o.Subscription == subscription));
if (_publishingCount == 0)
{
observers.ForEach(o => _observers.Remove(o));
}
else
{
_waitingUnsubscribers.AddRange(observers);
}
return observers.Count;
}
public void Publish(string message, object payload)
{
_publishingCount++;
Publish(_observers, message, payload);
Publish(_oneTimeObservers, message, payload);
Publish(_waitingSubscribers, message, payload);
_oneTimeObservers.RemoveAll(o => o.Subscription == message);
_waitingUnsubscribers.Clear();
_publishingCount--;
}
private void Publish(List<Observer> observers, string message, object payload)
{
Debug.Assert(_publishingCount >= 0);
var subscribers = observers.Where(o => o.Subscription.ToLower() == message.ToLower());
foreach (var subscriber in subscribers)
{
subscriber.Respond(payload);
}
}
public IEnumerable<Observer> GetObservers(string subscription)
{
var observers = new List<Observer>(_observers.Where(o => o.Subscription == subscription));
return observers;
}
public void Clear()
{
_observers.Clear();
_oneTimeObservers.Clear();
}
#region Helpers
private void Subscribe(string message, Action<object> response, List<Observer> observers)
{
Debug.Assert(_publishingCount >= 0);
var observer = new Observer() { Subscription = message, Respond = response };
if (_publishingCount == 0)
{
observers.Add(observer);
}
else
{
_waitingSubscribers.Add(observer);
}
}
#endregion
}
}
訂閱
public class Subscription
{
#region Members
List<Observer> _observerList = new List<Observer>();
#endregion
public void Unsubscribe(string subscription)
{
var observers = _observerList.Where(o => o.Subscription == subscription);
foreach (var observer in observers)
{
MessageBus.Instance.Unsubscribe(observer.Subscription, observer.Respond);
}
_observerList.Where(o => o.Subscription == subscription).ToList().ForEach(o => _observerList.Remove(o));
}
public void Subscribe(string subscription, Action<object> response)
{
MessageBus.Instance.Subscribe(subscription, response);
_observerList.Add(new Observer() { Subscription = subscription, Respond = response });
}
public void SubscribeFirstPublication(string subscription, Action<object> response)
{
MessageBus.Instance.SubscribeFirstPublication(subscription, response);
}
}
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