如何找出我按下了哪个按钮？

Question

想象一下 Facebook 的通知下拉菜单。 我想实现类似的东西。单击“Slet”时，应该从列表中删除该通知。

private void AddNotificationsToPanel(List<Notification> notifications, StackPanel panel)
{
    panel.Children.Clear();


    foreach (var notification in notifications)
    {
        //We want every message to have text, a delete button and a postpone button
        //So we need a nested stackpanel:
        var horizontalStackPanel = new StackPanel();
        horizontalStackPanel.Orientation = Orientation.Horizontal;
        panel.Children.Add(horizontalStackPanel);

        //Display the message:
        var text = new TextBlock();
        text.Text = notification.Message;
        text.Foreground = Brushes.Black;
        text.Background = Brushes.White;
        text.FontSize = 24;
        horizontalStackPanel.Children.Add(text);

        //Add a delete button:
        var del = new Button();
        del.Content = "Slet";
        del.FontSize = 24;
        del.Command = DeleteNotificationCommand;
        horizontalStackPanel.Children.Add(del);

        //Add a postpone button:
        var postpone = new Button();
        postpone.Content = "Udskyd";
        postpone.FontSize = 24;
        postpone.IsEnabled = false;
        horizontalStackPanel.Children.Add(postpone);
    }
    panel.Children.Add(new Button { Content = "Luk", FontSize = 24, Command = ClosePopupCommand });
}

基本上，我有一个垂直堆栈面板，其中有 x 个水平堆栈面板。每个都有一个文本框和两个按钮。 我怎么知道我点击了哪个按钮？这些按钮都绑定到一个删除命令，但我有点不确定它们是如何工作的：

public ICommand DeleteNotificationCommand
{
    get{
        return new RelayCommand(o => DeleteNotification());
    }
}

然后创建这个方法：

private void DeleteNotification()
{
    Notifications.Remove(NotificationForDeletion);
    AddNotificationsToPanel(Notifications, Panel);
}

问题是我们不知道要删除哪个通知，因为我不知道如何查看单击了哪个按钮。有什么想法吗？

Answer 1

您应该使用按钮的CommandParameter 属性，将每个通知的唯一标识符分配给它。我假设您的通知具有唯一的整数 id：

 //Add a delete button:
 var del = new Button();
 del.Content = "Slet";
 del.FontSize = 24;
 del.Command = DeleteNotificationCommand;
 del.CommandParameter = notification.Id; // <-- unique id
 horizontalStackPanel.Children.Add(del);

然后在DeleteNotification方法中，需要为key指定一个参数。

public ICommand DeleteNotificationCommand
{
    get{
        return new RelayCommand(DeleteNotification);
    }
}     
private void DeleteNotification(object parameter)
{
    int notificationId = (int)parameter;
    var NotificationForDeletion = ...;  // <--- Get notification by id
    Notifications.Remove(NotificationForDeletion);
    AddNotificationsToPanel(Notifications, Panel);
}

现在，您可以在 DeleteNotification 中识别与按钮相关的通知。