以编程方式调用 WPF TargetedTriggerAction

我有一个来自第 3 方库的 TargetedTriggerAction，它希望在不将其附加到按钮的情况下进行调用/调用。我可以让它与按钮一起工作，但我想这样做是为了响应一些非 UI 事件。

这是该操作的类声明：

 public class MeasureAction : TargetedTriggerAction<Map>

这是到目前为止我的设置代码：

    var measure = new MeasureAction();
    measure.TargetObject = _mapControl;
    measure.MeasureMode = MeasureAction.Mode.Polyline;
    measure.MapUnits = DistanceUnit.Miles;

我希望能够做这样的事情，但我知道 Invoke 受到保护：

measure.Invoke();

要调用触发器操作，您需要触发器！

namespace TriggerTest
{
    using System.Windows;

    /// <summary>
    /// A trigger that may be invoked from code.
    /// </summary>
    public class ManualTrigger : System.Windows.Interactivity.TriggerBase<DependencyObject>
    {
        /// <summary>
        /// Invokes the trigger's actions.
        /// </summary>
        /// <param name="parameter">The parameter value.</param>
        public void Invoke(object parameter)
        {
            this.InvokeActions(parameter);
        }
    }
}

上面是一个触发器实现，可以在没有任何 UI 依赖的情况下调用。例如：

var measure = new MeasureAction();
measure.TargetObject = _mapControl;
measure.MeasureMode = MeasureAction.Mode.Polyline;
measure.MapUnits = DistanceUnit.Miles; 

ManualTrigger trigger = new ManualTrigger();
trigger.Actions.Add(measure);
trigger.Invoke(null);

为了使调用更加容易，您可以添加扩展方法 to TriggerAction.

namespace TriggerTest
{
    using System.Windows.Interactivity;

    /// <summary>
    /// Allows a trigger action to be invoked from code.
    /// </summary>
    public static class TriggerActionExtensions
    {
        /// <summary>
        /// Invokes a <see cref="TriggerAction"/> with the specified parameter.
        /// </summary>
        /// <param name="action">The <see cref="TriggerAction"/>.</param>
        /// <param name="parameter">The parameter value.</param>
        public static void Invoke(this TriggerAction action, object parameter)
        {
            ManualTrigger trigger = new ManualTrigger();
            trigger.Actions.Add(action);

            try
            {
                trigger.Invoke(parameter);
            }
            finally
            {
                trigger.Actions.Remove(action);
            }
        }

        /// <summary>
        /// Invokes a <see cref="TriggerAction"/>.
        /// </summary>
        /// <param name="action">The <see cref="TriggerAction"/>.</param>
        public static void Invoke(this TriggerAction action)
        {
            action.Invoke(null);
        }
    }
}

现在你可以写下你真正想要的:

var measure = new MeasureAction();
measure.TargetObject = _mapControl;
measure.MeasureMode = MeasureAction.Mode.Polyline;
measure.MapUnits = DistanceUnit.Miles; 
measure.Invoke();