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正在开发一种新的post方法。我发现我在瓶颈foreach声明中遇到了极其漫长的等待时间。我节省了5到8K（取决于发送的项目）到数据库。该方法成功，但通常需要60秒以上的时间。我一直在研究如何实际执行一个异步方法，但我不确定这实际上能够解决问题。在foreach中实现异步.net 4.5 mvc
这是完整的方法
[HttpPost]
public ActionResult ConfirmSend(int? SystemGeneralAnnouncementId) {
var systemGeneralAnnouncement = (SystemGeneralAnnouncementId == null) ? null : _uow.SystemGeneralAnnouncementRepository.GetById(SystemGeneralAnnouncementId.Value);
List<Status> status = new List<Status>();
if (systemGeneralAnnouncement.Statuses.Length > 0)
{
status.AddRange(systemGeneralAnnouncement.Statuses.Split(',').Select(item => (Status) Enum.Parse(typeof (Status), item)));
}
var allEmailAddresses = new List<PointOfContact>();
var EmailAddresses = new List<PointOfContact>();
var result = new List<PointOfContact>();
foreach (var item in status)
{
result = _uow.PointOfContactRepository.GetAllByStatus(item).ToList();
allEmailAddresses.AddRange(result);
}
if (systemGeneralAnnouncement.SendToRecipients.Contains("(1) All Three Contact Types"))
{
mailAddresses = allEmailAddresses;
}
else
{
if (systemGeneralAnnouncement.SendToRecipients.Contains("(2) All Contacts "))
{
EmailAddresses.AddRange(allEmailAddresses.Where(r => r.PointOfContactType == PointOfContactTypes.Primary).ToList());
}
if (systemGeneralAnnouncement.SendToRecipients.Contains("(3) All Compliance contacts"))
{
pocEmailAddresses.AddRange(allEmailAddresses.Where(r => r.PointOfContactType == PointOfContactTypes.Secondary).ToList());
}
if (systemGeneralAnnouncement.SendToRecipients.Contains("(4) All Authorities"))
{
pocEmailAddresses.AddRange(allEmailAddresses.Where(r => r.PointOfContactType == PointOfContactTypes.SigningAuthority).ToList());
}
if (systemGeneralAnnouncement.SendToRecipients.Contains("(5) All Rate Contacts"))
{
EmailAddresses.AddRange(allEmailAddresses.Where(r => r.PointOfContactType == PointOfContactTypes.TuitionRates).ToList());
}
if (systemGeneralAnnouncement.SendToRecipients.Contains("(6) Specified Email Address"))
{
var pocs = new List<PointOfContact>();
string[] emails = systemGeneralAnnouncement.EmailAddresses.Split(',');
foreach (string email in emails)
{
var addContact = new InstitutionPointOfContact { Email = email };
User user = _uow.UserRepository.GetByEmail(email);
if (user == null)
{
addContact.FirstName = "Not Created Account Yet";
}
else
{
addContact.FirstName = user.FirstName;
addContact.LastName = user.LastName;
}
List<PointOfContact> idAssociatedToUser =
_uow.PointOfContactRepository
.GetAllByEmail(email)
.ToList();
if (idAssociatedToUser.Count == 0)
{
addContact.IDNumber = "N/A";
}
else
{
string[] opeidArray = opeidAssociatedToUser
.Select(x => x.OPEIDNumber)
.ToArray();
addContact.OPEIDNumber = string.Join(",", opeidArray);
}
Contacts.Add(addContact);
}
EmailAddresses.AddRange(Contacts);
}
}
具体Foreach
if (EmailAddresses.Count > 0)
{
foreach (PointOfContact emailAddress in EmailAddresses.Where(x => x.Email != "").ToList())
{
string firstName = emailAddress.FirstName == null ? "" : emailAddress.FirstName.Trim();
string lastName = emailAddress.LastName == null ? "" : emailAddress.LastName.Trim();
string userName = firstName + " " + lastName;
string emailBody = WebUtility.HtmlDecode(systemGeneralAnnouncement.EmailBody);
SaveToDatabase(emailAddress.Email, emailBody, systemGeneralAnnouncement.Subject, UserIdentityHelper.GetUserEmailAddress + " (" + UserIdentityHelper.GetUserId + ")", systemGeneralAnnouncement.SystemGeneralAnnouncementId, userName, emailAddress.OPEIDNumber);
LogInstitutionEmail(systemGeneralAnnouncement.Subject, emailBody, emailAddress.Email, emailAddress.OPEIDNumber, systemGeneralAnnouncement.EmailAttachmentLocation);
}
}
return View("GeneralAnnouncementGeneratedConfirmation");
}
和数据库的方法：
private void LogInstitutionEmail(string subject, string emailBody, string email, string opeidNumber, string emailAttachment)
{
try
{
using (var conn = new SqlConnection(ConfigurationManager.ConnectionStrings["MasterContext"].ConnectionString))
{
conn.Open();
var cmd = new SqlCommand("Insert Into InstitutionEmails (Since, Subject, Email, EmailAddress, OpeidNumber, FirstReadDateTime, Attachment) VALUES(@Since, @Subject, @Email, @EmailAddress, @idNumber, NULL, @Attachment)", conn);
cmd.CommandType = CommandType.Text;
cmd.Parameters.Add(new SqlParameter() { ParameterName = "@Since", Value = DateTime.Now });
cmd.Parameters.Add(new SqlParameter() { ParameterName = "@Subject", Value = subject });
cmd.Parameters.Add(new SqlParameter() { ParameterName = "@Email", Value = emailBody });
cmd.Parameters.Add(new SqlParameter() { ParameterName = "@EmailAddress", Value = email });
cmd.Parameters.Add(new SqlParameter() { ParameterName = "@idNumber", Value = idNumber });
if (!string.IsNullOrEmpty(emailAttachment))
{
cmd.Parameters.Add(new SqlParameter() { ParameterName = "@Attachment", Value = emailAttachment });
}
cmd.ExecuteNonQuery();
conn.Close();
}
}
catch (Exception ex)
{
}
}
private void SaveToDatabase(string emailRecipient, string emailBody, string subject, string userWhoSentIt, int systemGeneralAnnouncementId, string userName, string opeidNumber)
{
try
{
using (var conn = new SqlConnection(ConfigurationManager.ConnectionStrings["MasterContext"].ConnectionString))
{
conn.Open();
var cmd = new SqlCommand("Insert Into EmailQueue (EmailRecipients, EmailBody, EmailSubject, UserWhoSentIt, QueueDate, SystemGeneralAnnouncementId, UserName, idNumber) VALUES(@EmailRecipients, @EmailBody, @EmailSubject, @UserWhoSentIt, @QueueDate, @SystemGeneralAnnouncementId, @UserName, @idNumber)", conn);
cmd.CommandType = CommandType.Text;
cmd.Parameters.Add(new SqlParameter() {ParameterName = "@EmailRecipients", Value = emailRecipient });
cmd.Parameters.Add(new SqlParameter() { ParameterName = "@EmailBody", Value = emailBody });
cmd.Parameters.Add(new SqlParameter() { ParameterName = "@EmailSubject", Value = subject });
cmd.Parameters.Add(new SqlParameter() { ParameterName = "@UserWhoSentIt", Value = userWhoSentIt });
cmd.Parameters.Add(new SqlParameter() { ParameterName = "@QueueDate", Value = DateTime.Now });
cmd.Parameters.Add(new SqlParameter() { ParameterName = "@SystemGeneralAnnouncementId", Value = systemGeneralAnnouncementId });
cmd.Parameters.Add(new SqlParameter() { ParameterName = "@UserName", Value = userName });
cmd.Parameters.Add(new SqlParameter() { ParameterName = "@idNumber", Value = idNumber });
cmd.ExecuteNonQuery();
conn.Close();
}
}
catch (Exception ex)
{
}
}
我的问题是双重的。首先，我在研究中注意到，这种类型的代码（使用Sql server 2012）是异步可行的选择，如果您有数据库级别的瓶颈，异步可能会导致死锁。其次，如果异步/等待是可行的，那么实际执行它的最好方法是什么？
更新：post方法只是检索SystemGeneralAnnouncement的Id，以及启动该方法的确认。所有的实际执行都在方法本身内部处理。
更新2：对于澄清清酒，这些项目被传递给任务调度是火灾在以后的日子，并采取队列中的所有存储的项目，然后提供他们的背景。这就是我使用SQL调用的原因。
如果您执行异步/等待它将需要从底部到顶部完成。这是您调用的主要异步方法将在ADO.Net中，并且当您添加'await'时，您将使该方法成为'async'，并且这会引发您的控制器。然后，您会想要对控制器进行ajax调用，以使整个往返行程异步。 – juharr
@jpears，好吧，如果你想优化你的查询，你可能不应该在循环中打你的数据库，因为每次调用你都会得到很多额外的延迟。最重要的是，将电子邮件作为文本存储在文件系统上可能会更好，只需将路径存储到文本文件 –
@ johnny5感谢您的回复。如果我要将SavetoDatabase和LogInstitutionEmail方法移到循环之外，是否仍然最好将它们放入异步方法中？ – jpears