EWS 在 C# 中发送邮件失败，但在 VB.Net 中没有

Question

public ExchangeService CreateConnection(string url)
    {
        ServicePointManager.ServerCertificateValidationCallback = (object obj, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors) => true;
        ExchangeService service = new ExchangeService();
        service.Url = new Uri(url);
        service.UseDefaultCredentials = true;        // Uses users windows login credentials
        return service;
    }
public void SendEmail(string sEmailTo, string slocation, DateTime dtdate, string slogyard, string sScaling, string sLogMfct, string sOther, string sScaler, int icheckbox)
    {
        string scheckbox;
        string sDomain = Globals.gDefaultEmailSuffix;
        string sUserName = SystemInformation.UserName;
        ExchangeService service = CreateConnection("https://myexchangeserver.com/EWS/Exchange.asmx");
        string sHTMLpre = $"{EmailBody(Globals.gHTML)}";
        EmailMessage mailMessage = new EmailMessage(service);                 // Use with exchange service
                                                                     
        ReplaceWithBR(slogyard);
        ReplaceWithBR(sScaling);
        ReplaceWithBR(sLogMfct);
        ReplaceWithBR(sOther);

        if (icheckbox > 0)
            scheckbox = "Yes";
        else
            scheckbox = "No";

        sHTMLpre = sHTMLpre.Replace("[@Location]", slocation);
        sHTMLpre = sHTMLpre.Replace("[@Date]", dtdate.ToString());
        sHTMLpre = sHTMLpre.Replace("[@LogYard]", slogyard);
        sHTMLpre = sHTMLpre.Replace("[@Scaling]", sScaling);
        sHTMLpre = sHTMLpre.Replace("[@LogManufacturing]", sLogMfct);
        sHTMLpre = sHTMLpre.Replace("[@Scaler]", sScaler);
        sHTMLpre = sHTMLpre.Replace("[@Other]", sOther);
        sHTMLpre = sHTMLpre.Replace("[@RemotesExist]", scheckbox);

        mailMessage.ToRecipients.Add(new EmailAddress($"{sEmailTo}@{sDomain}"));     // Use with Exchange service
        mailMessage.From = new EmailAddress($"{sUserName}@{sDomain}");               // Use with Exchange service
        mailMessage.Subject = $"Scaling Yard Report for {slocation} on {dtdate}";    // Use with Exchange
        mailMessage.Body = sHTMLpre;                                                 // Use with Exchange
                    

        try
        {  
            mailMessage.SendAndSaveCopy());                    //Use with Exchange Service
            if (Globals.bLastEmail == true)
            {
                MessageBox.Show("Email Sent Successfully!");
                Globals.MonthlyLog("Email Sent", $"Recipients:{Globals.gEmailList}");
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
            Globals.MonthlyLog("Email Fail", $"{ex.Message}");

            return;
        }
    }

下面是运行良好的 VB.Net 代码：

Public Function CreateConnection(ByVal url As String) As ExchangeService
    ServicePointManager.ServerCertificateValidationCallback = Function(ByVal obj As Object, ByVal certificate As X509Certificate, ByVal chain As X509Chain, ByVal errors As SslPolicyErrors) True
    Dim service As New ExchangeService()
    service.Url = New Uri(url)
    service.UseDefaultCredentials = True        ' Uses users windows login credentials
    Return service
End Function
Public Sub SendEmail(sEmailTo As String, slocation As String, dtdate As String, slogyard As String, sScaling As String, sLogMfct As String, sOther As String, sScaler As String, scheckbox As String)
    Dim sDomain As String = gDefaultEmailSuffix
    Dim sUserName As String = SystemInformation.UserName
    Dim service As ExchangeService = CreateConnection("https://myexchangeserver.com/EWS/Exchange.asmx")
    Dim sHTMLpre As String = $"{EmailBody(gHTML)}"
    Dim mailMessage = New EmailMessage(service)                 ' Use with exchange service
    'Dim mailMessage As New MailMessage()                       ' Use with SMTP client service

    slogyard = slogyard.Replace(ControlChars.Lf, "<br>")
    sScaling = sScaling.Replace(ControlChars.Lf, "<br>")
    sLogMfct = sLogMfct.Replace(ControlChars.Lf, "<br>")
    sOther = sOther.Replace(ControlChars.Lf, "<br>")

    If scheckbox = True Then
        scheckbox = "Yes"
    Else
        scheckbox = "No"
    End If

    sHTMLpre = sHTMLpre.Replace("[@Location]", slocation)
    sHTMLpre = sHTMLpre.Replace("[@Date]", dtdate)
    sHTMLpre = sHTMLpre.Replace("[@LogYard]", slogyard)
    sHTMLpre = sHTMLpre.Replace("[@Scaling]", sScaling)
    sHTMLpre = sHTMLpre.Replace("[@LogManufacturing]", sLogMfct)
    sHTMLpre = sHTMLpre.Replace("[@Scaler]", sScaler)
    sHTMLpre = sHTMLpre.Replace("[@Other]", sOther)
    sHTMLpre = sHTMLpre.Replace("[@RemotesExist]", scheckbox)

    mailMessage.ToRecipients.Add(New EmailAddress($"{sEmailTo}@{sDomain}"))     ' Use with Exchange service
    mailMessage.From = New EmailAddress($"{sUserName}@{sDomain}")               ' Use with Exchange service
    mailMessage.Subject = $"Scaling Yard Report for {slocation} on {dtdate}"    ' Use with Exchange
    mailMessage.Body = sHTMLpre                                                 ' Use with Exchange

    'mailMessage.IsBodyHtml = True                                              ' Use with SMTP CLient
    'mailMessage.To.Add($"{sEmailTo}@{sDomain}")                                ' Use with SMTP CLient
    'mailMessage.From = New MailAddress($"{sUserName}@{sDomain}")               ' Use with SMTP  
    'mailMessage.Subject = $"Scaling Yard Report for {slocation} on {dtdate}"   ' Use with SMTP
    'mailMessage.Body = sHTMLpre                                                ' Use with SMTP


    'Dim SmtpCli As New SmtpClient()                                            ' Leaving this just in case the EWS breaks
    'With SmtpCli                                                               ' SMTP Client Code
    '    .UseDefaultCredentials = False
    '    .Port = 25
    '    .DeliveryMethod = SmtpDeliveryMethod.Network
    '    .Host = gSMTPServer
    '    .Credentials = New NetworkCredential(gSMTPUsername, gSMTPPassword)
    'End With

    Try
        'SmtpCli.Send(mailMessage)                                              ' Use with SMPT client
        mailMessage.SendAndSaveCopy()                                           ' Use with Exchange Service
        If bLastEmail = True Then
            MsgBox("Email Sent Successfully!")
            Call MonthlyLog("Email Sent", $"Recipients:{gEmailList}")
        End If
    Catch ex As Exception
        MessageBox.Show(ex.Message)
        Call MonthlyLog("Email Fail", $"{ex.Message}")

        Exit Sub
    End Try

End Sub

它在以下行失败：mailMessage.SendAndSaveCopy() - 在 C# 中但不是 VB.Net

收到错误：“请求失败。基础连接已关闭：发送时发生意外错误”

正如我所说，它与 vb.net 代码一起工作正常，所以它不是像限制这样的交换服务器设置。有什么想法吗？

Answer 1

需要将目标 .Net Framework 更新到至少 4.6 或更高版本。我正在使用 4.5。应该知道，因为我运行遇到 vb.net 程序的问题，无法在旧的未更新的 32 位 Windows 10 台没有 4.6 的 PC 上发送电子邮件。

EWS 在 C# 中发送邮件失败，但在 VB.Net 中没有

EWS sending mail fails in C# but not in VB.Net

c#

vb.net

email

exchangewebservices