以编程方式调用WPF TargetedTriggerAction [英] Programmatically Call WPF TargetedTriggerAction

问题描述

我有一个来自第三方库的TargetedTriggerAction，它想在不将其附加到按钮的情况下进行调用/调用。我可以使用按钮来操作它，但是我想响应某些非UI事件。

I have a TargetedTriggerAction from a 3rd party library that would like to call/invoke without attaching it to a button. I have no problem getting it to work with the button, but I want to do it in response to some non-UI event.

这是操作的类声明：

 public class MeasureAction : TargetedTriggerAction<Map>

到目前为止，这是我的设置代码：

Here is my setup code so far:

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

我希望能够执行类似的操作，但是我知道Invoke受保护：

I want to be able to do something like this, but I know Invoke is protected:

measure.Invoke();

推荐答案

要调用触发操作，您需要一个触发！

To invoke your trigger action, you need a trigger!

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);
        }
    }
}

以上是触发实现可以在没有任何UI依赖项的情况下调用。例如：

The above is a trigger implementation that may be invoked without any UI dependencies. For example:

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);

要使调用更加简单，您可以添加扩展方法 TriggerAction 。

To make calling this even easier, you could add an extension method 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);
        }
    }
}

现在您可以写下您真正想要的东西：

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

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