Question

在.Net framework 4.5中引入async和await关键字来执行异步调用。

我也在Web应用程序中使用过它们。我开始知道也可以使用代表来完成。

以下是我的示例代码段，其中显示了如何完成异步调用

               Public void binddata()
                {
                certificate = HelperMethods.GetStoreCertifcate(Thumbprint);
                ListHostedServices(SubscriptionId, certificate, Version);
                hostedservicesview.ActiveViewIndex = 0;
                ListStorageAccounts(SubscriptionId, certificate, Version);
                }

 public async void ListHostedServices(string subscriptionId, X509Certificate2 certificate, string version)
        {

            string hittingUri = String.Format("https://management.core.windows.net/{0}/" + "services/hostedservices",SubscriptionId);
             XmlDocument responsebody= await HelperMethods.GetXmlDocument(hittingUri, certificate, version);

             if (responsebody != null)
             {
                 var result = responsebody.GetElementsByTagName("HostedServiceProperties");



                 hostedservices = new DataTable();
                 hostedservices.Columns.Add("Url");
                 hostedservices.Columns.Add("ServiceName");

                 hostedservices.Columns.Add("Location");
                 hostedservices.Columns.Add("Label");
                 hostedservices.Columns.Add("Status");
                 hostedservices.Columns.Add("DateCreated");
                 hostedservices.Columns.Add("DateLastModified");
                 foreach (XmlNode hsnode in result)
                 {
                     DataRow hsrow = hostedservices.NewRow();
                     hsrow["Url"] = hsnode.ParentNode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "Url").Any() ?
                             hsnode.ParentNode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "Url").First().InnerText : string.Empty;
                     hsrow["ServiceName"] = hsnode.ParentNode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "ServiceName").Any() ?
                            hsnode.ParentNode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "ServiceName").First().InnerText : string.Empty;
                     hsrow["Location"] = hsnode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "Location").Any() ?
                           hsnode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "Location").First().InnerText : string.Empty;

                     // IF location is empty, it means affinity group is returned, Pull location from affinity group
                     if (String.IsNullOrEmpty(hsrow["Location"].ToString()))
                     {
                         string affnitygroup = hsnode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "AffinityGroup").Any() ?
                            hsnode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "AffinityGroup").First().InnerText : string.Empty;

                         certificate = HelperMethods.GetStoreCertifcate(Thumbprint);
                         hsrow["Location"] = await HelperMethods.GetAffinityGroupLocation(subscriptionId, certificate, Version, affnitygroup);


                     }
                     hsrow["Label"] = hsnode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "Label").Any() ?
                          hsnode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "Label").First().InnerText : string.Empty;
                     hsrow["Status"] = hsnode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "Status").Any() ?
                         hsnode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "Status").First().InnerText : string.Empty;
                     hsrow["DateCreated"] = hsnode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "DateCreated").Any() ?
                        hsnode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "DateCreated").First().InnerText : string.Empty;
                     hsrow["DateLastModified"] = hsnode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "DateLastModified").Any() ?
                       hsnode.ChildNodes.OfType<XmlElement>().Where(x => x.Name == "DateLastModified").First().InnerText : string.Empty;
                     hostedservices.Rows.Add(hsrow);

                 }
                 lbl_count.Text = hostedservices.Rows.Count.ToString();
                 HostedServicesList.DataSource = hostedservices;
                 HostedServicesList.DataBind();

             }

            else
            {

            }




        }

**XmlDocument responsebody= await HelperMethods.GetXmlDocument(hittingUri, certificate, version);**
The method definition is as follows
 public static async Task<XmlDocument> GetXmlDocument(string hittingUrl, X509Certificate2 certificate, string Version)
        {
            HttpWebRequest request;
              XmlDocument responsebody = new XmlDocument();
            // string hittingUri = "https://management.core.windows.net/{0}/" + "services/hostedservices";
            Uri uri = new Uri(hittingUrl);


            request = (HttpWebRequest)HttpWebRequest.Create(uri);

            request.Method = "GET";
            request.Headers.Add("x-ms-version", Version);

            request.ClientCertificates.Add(certificate);
            request.ContentType = "application/xml";




            HttpWebResponse webresponse= null;

            try
            {
                webresponse = (HttpWebResponse)await request.GetResponseAsync();

            }
            catch (Exception)
            {

            }

            HttpStatusCode statuscode = webresponse.StatusCode;
            if (webresponse.ContentLength > 0)
            {
                using (XmlReader reader =XmlReader.Create(webresponse.GetResponseStream()))
                {
                    responsebody.Load(reader);


                }
            }

            if (statuscode.Equals(HttpStatusCode.OK))
            {
                return responsebody;
            }
            else
            {
                return null;
            }


        }

同样，上述2种方法也有同样的列表。

我花了大约12-15秒来检索11 + 19 + 6条记录的数据。

你们可以帮助我优化这段代码，以便它更快。

Answer 1

首先，您需要对代码进行分析，以确定您在哪里浪费时间。如果GetXMLDocument占用大部分时间，则可能是服务器没有响应

除此之外，我的猜测是你的foreach循环花费了大量的时间，因为你实际上是在搜索每个语句中的所有元素。

另一种方法是

Dictionary<string, string> nvpairsForColumns = new Dictionary { "Url", String.Empty }; // add all valid column headers here
foreach(var xelement in hsnode.ParentNode.ChildNodes.OfType<XmlElement>)
{
  if(nvparisForColumns.ContainsKey(xelement.Name)
     && String.IsNullOrEmpty(nvpairsForColumns[xlement.Name])) // assumption String.Empty is not a valid entry else keep another Dictionary<string,bool> to tag when done with first
  {
     nvpairsForColumns[xelement.Name] = xelement.InnerText;
  }

}

使用Async和Await进行异步调用

1 个答案: