c# - WebClient 异常，不支持并发 I/O 操作

Question

我有一个静态类，它返回 webclient 的新实例

public static class WebAccess
{
    public static WebClient GetWebClient()
    {
        return new WebClient();
    }
}

然后我用这个类来点击这样的页面

WebAccess.GetWebClient().DownloadString(new Uri("http://" + WLCDomainUrl + ConfigurationManager.AppSettings["urlClearCache"].ToString() + "/?id=" + Request.QueryString["id"] + "&Type=RC"));

我不想赶上回应

但它大部分时间都在抛出异常

WebClient does not support concurrent I/O operations.

Stack Trace:

   at System.Net.WebClient.ClearWebClientState()
   at System.Net.WebClient.DownloadString(Uri address)
   at UpdateCache.ProcessLocationCacheRequest(String locId, Boolean isChain) in 

WebClient does not support concurrent I/O operations.

Stack Trace:

   at System.Net.WebClient.ClearWebClientState()
   at System.Net.WebClient.UploadString(Uri address, String method, String data)
   at System.Net.WebClient.UploadString(String address, String data)
   at CacheClassLibrary.ServerClass.APIServer.Create(String Id, String MobileWLCUrl) in 

有什么帮助吗？？我无法理解它，因为我正在使用新的 Web 客户端实例为每个请求提供服务：/

应用程序同时收到多个请求。

Answer 1

尝试这个

public static class WebAccess
{
    WebClient instance;
    public static WebClient GetWebClient()
    {
        if (instance == null)
           instance = new WebClient();

        return instance;
    }
}

那么你只有一个 WebClient 类的实例