Windows Phone 7开发遇到的事：使用get、post请求

 

当要向服务器发送get或post请求的时候，WP7一般会用到HttpWebRequst或WebClient这两种方法。

两者最大的区别：HttpWebRequst的回调是异步，WebClient的回调是同步。

我更喜欢用HttpWebRequst，下面是用法：

 

GET

 

string uri = "https://www.google.com/";

HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(uri);
httpWebRequest.BeginGetResponse(ResponseCallback, httpWebRequest);

private void ResponseCallback(IAsyncResult result)
{
    string response = null;
    Stream stream = null;

    try
    {
        //获取异步操作返回的的信息 
        HttpWebRequest httpWebRequest = (HttpWebRequest)result.AsyncState;
        //结束对 Internet 资源的异步请求
        WebResponse webResponse = httpWebRequest.EndGetResponse(result);
        stream = webResponse.GetResponseStream();
        using (StreamReader sr = new StreamReader(stream))
        {
            response = sr.ReadToEnd();
        }       
    }
    catch { }
    finally
    {
        if (stream != null)
        {
            stream.Close();
        }
    }

    //这里不为空代表获得回复了
    if (response != null)
    {
        //因为HttpWebRequest的回调是异步，不在UI线程上。所以要改变UI线程上的控件属性就要用Dispatcher.BeginInvoke()。
        Dispatcher.BeginInvoke(() =>
        {
          textBlock.Text = response;
        });
    }
} 

POST

string uri = "https://www.google.com/";

HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(uri);
httpWebRequest.Method = "POST";
httpWebRequest.ContentType = "application/x-www-form-urlencoded";
httpWebRequest.BeginGetRequestStream(StreamCallback, httpWebRequest);

这里是先获得向服务器写入的一个流，比如要向服务器发送一个字符串“啦啦啦”（注意编码）：

private void StreamCallback(IAsyncResult result)
{
    HttpWebRequest httpWebRequest = (HttpWebRequest)result.AsyncState;

    using (Stream stream = httpWebRequest.EndGetRequestStream(result))
    {
        byte[] entryBytes = Encoding.UTF8.GetBytes("啦啦啦");
        stream.Write(entryBytes, 0, entryBytes.Length);
    }

    //这里就和上面GET方法获得回复回调一样，用 private void ResponseCallback(IAsyncResult result) 这个方法。
    httpWebRequest.BeginGetResponse(ResponseCallback, httpWebRequest);
}