Question

有没有办法根据Click事件的某些条件停止执行Button命令？

实际上我想在我们的应用程序中点击一些按钮确认弹出窗口。为了使其成为一般解决方案，我做了以下工作：

我有WPF按钮类调用AppBarButton的扩展，它已经包含一些依赖属性。
我还有以下两个属性：IsActionConfirmationRequired和ConfirmationActionCommand。

如果IsActionConfirmationRequired然后左按钮cick事件我打开确认弹出窗口。

有没有办法避免创建新的ConfirmationActionCommand，并使用Command的相同Button属性？如果我设置Command，然后在Button点击即使用户未确认操作仍然按钮命令执行，我会遇到问题。

C＃：

public class AppBarButton : Button
{
    public AppBarButton()
    {
        this.Click += AppBarButton_Click;
    }

    private void AppBarButton_Click(object sender, RoutedEventArgs e)
    {
        Button button = sender as Button;
        if (button == null || IsActionConfirmationRequired == false || ConfirmationActionCommand == null)
            return;

        const string defaultMessage = "Do you really want to {0}";

        string confirmationPopUpMessage = string.IsNullOrEmpty(ActionConfirmationMessage)
          ? DebugFormat.Format(defaultMessage, button.Content)
          : ActionConfirmationMessage;

        ConfirmationDailogDetails confirmationDailogDetails = new ConfirmationDailogDetails
        {
            Message = confirmationPopUpMessage,
            ActionName = button.Content.ToString(),
            Template = button.Template,
            ActionCommand = ConfirmationActionCommand
        };

        //instead of ConfirmationActionCommand want to use base.Command
        ConfirmationDailog dialog = new ConfirmationDailog(confirmationDailogDetails)
        {
            PlacementTarget = button,
            IsOpen = true
        };
    }

    public static readonly DependencyProperty IsActionConfirmationRequiredProperty =
        DependencyProperty.Register("IsActionConfirmationRequired", typeof(bool), typeof(AppBarButton));

    public static readonly DependencyProperty ActionConfirmationMessageProperty =
        DependencyProperty.Register("ActionConfirmationMessage", typeof(string), typeof(AppBarButton));

    public static readonly DependencyProperty ConfirmationActionCommandProperty =
       DependencyProperty.Register("ConfirmationActionCommand", typeof(ICommand), typeof(AppBarButton));

    /// <summary>
    /// Gets or sets the flag to show the confirmation popup on before taking any action on App Bar button click.
    /// Also its required to set the command in Tag Property of the App Bar button not in the Command Property, then only required command will fire only when user
    /// confirms and click on the action button on confirmation popup.
    /// </summary>
    public bool IsActionConfirmationRequired
    {
        get { return (bool)GetValue(IsActionConfirmationRequiredProperty); }
        set { SetValue(IsActionConfirmationRequiredProperty, value); }
    }

    /// <summary>
    /// Gets or sets the confirmation message in confirmation popup  before taking any action on App Bar button click.
    /// </summary>
    public ICommand ConfirmationActionCommand
    {
        get { return (ICommand)GetValue(ConfirmationActionCommandProperty); }
        set { SetValue(ConfirmationActionCommandProperty, value); }
    }
}

XAML：

<controls:AppBarButton x:Key="WithdrawAll"
                       AppBarOrder="1"
                       PageIndex="1"
                       AppBarOrientation="Left"
                       Content="Withdraw" IsActionConfirmationRequired="True"
                       ConfirmationActionCommand="{Binding WithdrawAllCommand}"
                       Template="{StaticResource DeleteCircleIcon}" />

请提出建议。我找不到任何东西。已经尝试CanExecute为false，但其make按钮禁用，因此没有用。我只是简单地想要发出另一个命令，而使用此AppBarButton的开发人员需要将ConfirmationActionCommand设置为不正常Command。

Answer 1

如果我正确理解，您要确认用户的操作并执行存储在ButtonBase.Command属性中的命令。

要实现此目的，请删除ConfirmationActionCommand属性并使用OnClick方法而不是Click事件。在重写OnClick方法中，调用基本方法，如果用户确认某个操作或者不需要确认，则该方法将从Command属性执行命令。

public class AppBarButton : Button
{
    public static readonly DependencyProperty IsActionConfirmationRequiredProperty =
        DependencyProperty.Register("IsActionConfirmationRequired", typeof(bool), typeof(AppBarButton));

    public static readonly DependencyProperty ActionConfirmationMessageProperty =
        DependencyProperty.Register("ActionConfirmationMessage", typeof(string), typeof(AppBarButton));

    public bool IsActionConfirmationRequired
    {
        get { return (bool)GetValue(IsActionConfirmationRequiredProperty); }
        set { SetValue(IsActionConfirmationRequiredProperty, value); }
    }

    public string ActionConfirmationMessage
    {
        get { return (string)GetValue(ActionConfirmationMessageProperty ); }
        set { SetValue(ActionConfirmationMessageProperty , value); }
    }

    protected override void OnClick()
    {
        bool confirmed = true;

        if (IsActionConfirmationRequired)
        {
            ConfirmationDailogDetails confirmationDailogDetails = new ConfirmationDailogDetails
            {
                Message = confirmationPopUpMessage,
                ActionName = button.Content.ToString(),
                Template = button.Template,
                ActionCommand = ConfirmationActionCommand
            };

            ConfirmationDailog dialog = new ConfirmationDailog(confirmationDailogDetails)
            {
                PlacementTarget = button,
                IsOpen = true
            };

            // Set confirmed here

            // If you set the DialogResult property in the ConfirmationDailog class then
            // confirmed = dialog.ShowDialog().Value;
        }

        // If there is no confirmation requred or if an user have confirmed an action
        // then call base method which will execute a command if it exists.
        if (confirmed)
        {
            base.OnClick();
        }
    }
}

Answer 2

代替click事件，处理PreviewMouseLeftButtonDown事件。这在命令执行之前发生。在处理程序中请求确认并将Handled的{{1}}属性设置为true或false 如果将其设置为true，则不会执行该命令。

event

以下是您的代码的外观（我完全不知道，因为我没有private void btn_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e) { var confirmed = true; //use your confirmation instead e.Handled = confirmed; }的代码：

ConfirmationDailog

如何从Click事件WPF

2 个答案: