问题的结果传递给调用者异步HttpWebRequest的 [英] Problem to pass the result to the caller for asynchronous httpWebRequest

问题描述

在Silverlight中我希望能够得到来自Helper类的输出是这样的：

  MainPage的公（）
    {
        的InitializeComponent（）;

        字符串输出中;
        助手帮手=新助手（URL）;

        Helper.invoke（输出）;

    }
 

我不明白怎么做，因为在辅助类，我有责任做一个异步调用：

 私人字符串webserviceUrl;
    私人XDOC的XDocument =新的XDocument（）;

    公共助手（字符串webserviceUrl）
    {
        this.webserviceUrl = webserviceUrl;
    }

    公共无效的invoke（REF字符串输出）
    {

        HttpWebRequest的HttpWebRequest的=（HttpWebRequest的）WebRequest.Create（this.webserviceUrl）;
        尝试
        {
            HttpWebResponse httpWebResponse =（HttpWebResponse）httpWebRequest.BeginGetResponse（新的AsyncCallback（HandlerWebResponse），httpWebResponse）;

        }
        抓住
        {

        }

  }

    私人无效HandlerWebResponse（IAsyncResult的asynchronousResult）
    {
        HttpWebRequest的要求=（HttpWebRequest的）asynchronousResult.AsyncState;
        HttpWebResponse响应=（HttpWebResponse）request.EndGetResponse（asynchronousResult）;
        使用（StreamReader的streamReader1 =新的StreamReader（response.GetResponseStream（）））
        {
            字符串resultString = streamReader1.ReadToEnd（）;

        }
    }
 

解决方案

创建事件通知该服务已成功使用。在事件参数可以传递的调用Web服务的结果。

 公共事件动作＆LT;字符串＆GT; ResponseResult;
 

您就可以在您的网络响应处理程序调用此事件：

 私人无效HandlerWebResponse（IAsyncResult的asynchronousResult）
{
    HttpWebRequest的要求=（HttpWebRequest的）asynchronousResult.AsyncState;
    HttpWebResponse响应=（HttpWebResponse）request.EndGetResponse（asynchronousResult）;
    使用（StreamReader的streamReader1 =新的StreamReader（response.GetResponseStream（）））
    {
        字符串resultString = streamReader1.ReadToEnd（）;
        如果（ResponseResult！= NULL）
             ResponseResult（resultString）;

    }
}
 

和在$ C C同修的服务电话，您可以订阅该事件得到通知时，它已经完成$：

 辅助帮手=新助手（URL）;
MainPage的公（）
{
    的InitializeComponent（）;

    Helper.ResponseResult + = ResponseHandler的;
    Helper.invoke（输出）;

}

公共无效ResponseHandler所（字符串响应）
{
    //做些事情的反应
}
 

In Silverlight I want to be able to get the output from a Helper class like this:

    public MainPage()
    {
        InitializeComponent();

        String ouput;
        Helper helper = new Helper(url);

        Helper.invoke(output);

    }

I can't see how to do that since in Helper Class I am obliged to do an asynchronous call:

    private String webserviceUrl;
    private XDocument xdoc = new XDocument();

    public Helper(String webserviceUrl)
    {
        this.webserviceUrl = webserviceUrl;
    }

    public void invoke(ref String output)
    {

        HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(this.webserviceUrl);
        try
        {
            HttpWebResponse httpWebResponse = (HttpWebResponse)httpWebRequest.BeginGetResponse(new AsyncCallback(HandlerWebResponse), httpWebResponse);

        }
        catch
        {

        }

  }

    private void HandlerWebResponse(IAsyncResult asynchronousResult)
    {
        HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
        HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
        using (StreamReader streamReader1 = new StreamReader(response.GetResponseStream()))
        {
            string resultString = streamReader1.ReadToEnd();

        }
    }

解决方案

Create an event to notify that the service has been successfully consumed. In the event parameters you can pass the result of the invoked web services.

public event Action<string> ResponseResult;

You can then invoke this event in your web response handler:

private void HandlerWebResponse(IAsyncResult asynchronousResult)
{
    HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
    HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
    using (StreamReader streamReader1 = new StreamReader(response.GetResponseStream()))
    {
        string resultString = streamReader1.ReadToEnd();
        if (ResponseResult != null)
             ResponseResult(resultString);

    }
}

And in your code the initiates the service call you can subscribe to this event to get notified when it has finished:

Helper helper = new Helper(url);
public MainPage()
{
    InitializeComponent();

    Helper.ResponseResult += ResponseHandler;
    Helper.invoke(output);

}

public void ResponseHandler(string response)
{
    // do something with response
}

这篇关于问题的结果传递给调用者异步HttpWebRequest的的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！