如何等待对web服务的调用完成

本文关键字：服务 调用 web 何等待 等待 | 更新日期: 2023-09-27 18:30:04

我正在尝试从web服务获取FedAuth Cookie。但实际情况是，在我从web服务获得结果之前，另一个方法GetFedAuthCookieFromSOAPResponse方法正在执行，传递给它的参数变成了null。因此，我得到了一个例外：

startIndex不能大于字符串的长度。参数名称：startIndex

如何等待从web服务获得soap响应，然后执行方法GetFedAuthCookieFromSOAPResponse？

static void Main(string[] args)
        {
            string url = "https://server/site";
            string soapResponse = GetSOAPResponse(url, "http://site/server/exapmle.asmx");
            Console.WriteLine(GetFedAuthCookieFromSOAPResponse(soapResponse));
            Console.WriteLine("Press ENTER to close program");
            Console.ReadLine();
        }
        internal static string GetSOAPResponse(string url, string serviceURL)
        {
            using (WebClient client = new WebClient())
            {
                string request = "<?xml version='"1.0'" encoding='"utf-8'"?><soap:Envelope xmlns:xsi='"http://www.w3.org/2001/XMLSchema-instance'" xmlns:xsd='"http://www.w3.org/2001/XMLSchema'" xmlns:soap='"http://schemas.xmlsoap.org/soap/envelope/'"><soap:Body><GetFedAuthCookie xmlns='"http://tempuri.org/'"><requestUrl>" + url + "</requestUrl><userName></userName><password></password></GetFedAuthCookie></soap:Body></soap:Envelope>";
                client.Headers.Add(HttpRequestHeader.ContentType, "text/xml; charset=utf-8");
                client.Headers.Add("SOAPAction", "http://tempuri.org/GetFedAuthCookie");
                string soapResult = string.Empty;
                client.UploadString(new Uri(serviceURL), request);
                client.UploadStringCompleted += new UploadStringCompletedEventHandler(delegate(object sender, UploadStringCompletedEventArgs e)
                {
                    soapResult = e.Result;
                });                
                return soapResult;
            }
        }
        internal static string GetFedAuthCookieFromSOAPResponse(string soapResponse)
        {
            string openingTag = "<GetFedAuthCookieResult>";
            string closingTag = "</GetFedAuthCookieResult>";
            int startIndex = soapResponse.IndexOf(openingTag) + openingTag.Length;
            int length = soapResponse.IndexOf(closingTag) - startIndex;
            return soapResponse.Substring(startIndex, length);
        }

如何等待对web服务的调用完成

UploadString已经是一个同步方法。这意味着当方法返回时，操作已经完成。CCD_ 5仅在处理像UploadStringAsync或UploadStringTaskAsync这样的异步方法时使用。

UploadString返回一个字符串，该字符串是来自服务器的响应。

你只需要

string soapResult = client.UploadString(new Uri(serviceURL), request);
return soapResult;

这是您响应web服务请求完成的地方：

client.UploadStringCompleted += new UploadStringCompletedEventHandler(delegate(object sender, UploadStringCompletedEventArgs e)
{
    soapResult = e.Result;
});

所以你可以在那里执行你的后续逻辑：

client.UploadStringCompleted += new UploadStringCompletedEventHandler(delegate(object sender, UploadStringCompletedEventArgs e)
{
    Console.WriteLine(GetFedAuthCookieFromSOAPResponse(e.Result));
    Console.WriteLine("Press ENTER to close program");
    Console.ReadLine();
});

或者，您可以将该逻辑重构为一个方法，并从中调用该方法，等等。

但本质上，由于这是一个异步操作，您不会"等到它完成"，而是"响应它的完成事件"。

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