如何将一个JavaScript函数传递给Silverlight？ [英] How can I pass a JavaScript function to Silverlight?

问题描述

我正在评估JavaScript / Silverlight互操作功能，并且已经能够使用JavaScript和调用方法创建一个Silverlight实例。但是，我现在需要一种将JavaScript回调函数传递给Silverlight的方法。

I'm evaluating the JavaScript/Silverlight interop capabilities and have been able to create a Silverlight instance using JavaScript and call methods on it. However, I now need a way of passing a JavaScript callback function to Silverlight.

只要将JavaScript函数传递给Silverlight方法，建议它的目的。我缺少什么？异常详细信息：

Simply passing a JavaScript function to a Silverlight method expecting an Action doesn't work although the error suggest that it's intended to. What am I missing? The exception details:

Microsoft JScript runtime error: System.ArgumentException: Cannot bind to the target method because its signature or security transparency is not compatible with that of the delegate type.
   at System.Delegate.CreateDelegate(Type type, Object firstArgument, MethodInfo method, Boolean throwOnBindFailure)
   at System.Windows.Hosting.ScriptingInterface.GetDelegateForScriptObject(Type eventHandlerType, ScriptObject obj)
   at System.Windows.Browser.ScriptObject.ConvertTo(Type targetType, Boolean allowSerialization)
   at System.Windows.Hosting.ScriptingInterface.GetScriptParamValueForType(ScriptParam scriptParam, Type desiredType)
   at System.Windows.Hosting.ScriptingInterface.ConvertFromScriptParams(ParameterInfo[] parameters, ScriptParam[] args)
   at System.Windows.Browser.ManagedObjectInfo.ScriptMethod.Invoke(ManagedObject obj, InvokeType invokeType, ScriptParam[] args)
   at System.Windows.Browser.ManagedObjectInfo.Invoke(ManagedObject obj, InvokeType invokeType, String memberName, ScriptParam[] args)
   at System.Windows.Hosting.ManagedHost.InvokeScriptableMember(IntPtr pHandle, Int32 nMemberID, Int32 nInvokeType, Int32 nArgCount, ScriptParam[] pArgs, ScriptParam& pResult, ExceptionInfo& pExcepInfo)

推荐答案

没有看到你的代码我不能说什么是错误的，但我可以描述过去为我工作。

Without seeing your code I cannot say what you are doing wrong but I can describe what has worked for me in the past.

在Silverlight侧，你需要注册一个类作为一个脚本对象。然后创建一个标记为ScriptableMember的方法，并接受将在JavaScript方法中传递的字符串。我还添加了一个名为InvokeCallback的方法，它将调用传入的javascript回调。

On the Silverlight side you need to register a class as a scriptable object. Then create a method that is marked as a ScriptableMember and takes a string that will be your passed in JavaScript method. I also added a method called InvokeCallback which will invoke the passed in javascript callback.

[ScriptableType]
public partial class Page : UserControl
{
    private string jsCallback;
    public Page()
    {
        InitializeComponent();
        HtmlPage.RegisterScriptableObject("silverlightInterop", this);
    }


    [ScriptableMember]
    public void RegisterCallback(string callback)
    {
      jsCallback = callback;
    }

    public boid InvokeCallback(string arg)
    {
      if(!string.IsNullOrEmpty(jsCallback))
      {
          System.Windows.Browser.HtmlPage.Window.Invoke(jsCallback, arg);
      }
    }
}

调用您在Silverlight中定义的RegisterCallback方法，方法是抓取页面上的silverlight对象，并调用名为silverlightInterop的方法，我们注册为可脚本对象的名称。

On the JavaScript side you can call the RegisterCallback method that you defined in Silverlight by grabbing the silverlight object on the page and calling the method off of the name "silverlightInterop" which we registered as the name of our scriptable object.

function jsCallback(someArg) {
   alert(someArg);
}

var silverLightControl = document.getElementById("silverlightControl");
silverLightControl.content.silverlightInterop.RegisterCallback("jsCallback");

我希望这有帮助。我还有一些示例代码演示了我之前写的这里

I hope this helps. I also have some sample code the demonstrates this which I wrote a while ago here

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