c# - 如何从其 Click 事件 WPF 中停止按钮命令的执行

Question

有什么方法可以根据点击事件的某些条件来停止 Button 命令的执行吗？

实际上，我想在我们的应用程序中点击某些按钮时弹出确认窗口。为了使其成为通用解决方案，我做了以下工作:

1. 我有 WPF 按钮类调用 AppBarButton 的扩展，它已经包含一些依赖属性。
2. 我还有 2 个属性，如下所示:IsActionConfirmationRequired 和 ConfirmationActionCommand。

如果 IsActionConfirmationRequired 然后在左键单击事件中我将打开确认弹出窗口。

有没有办法避免创建新的 ConfirmationActionCommand，并使用 Button 的相同 Command 属性？我遇到的问题是，如果我设置了 Command，然后在 Button 上单击，即使用户未确认操作仍然按钮命令执行。

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}" />

请提出一些建议。我找不到任何东西。已经尝试将 CanExecute 设置为 false，但是它的 make 按钮被禁用所以没有用。我只是不想创建另一个命令，使用此 AppBarButton 的开发人员需要将 ConfirmationActionCommand 设置为非正常的 Command。

Answer 1

如果我理解正确的话，你想要确认用户的操作并执行存储在 ButtonBase.Command 属性中的命令。

要实现这一点，请删除 ConfirmationActionCommand 属性并使用 OnClick 方法而不是 Click 事件。在覆盖的 OnClick 方法中调用基本方法，如果用户确认操作或不需要确认，该方法将执行来自 Command 属性的命令。

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();
        }
    }
}