我使用C#库发送一封带有标志的电子邮件。当我通过GMail的SMTP服务器发送此电子邮件时,图像是可见的。当我使用我们的域名admin@domaine.net发送时,图像不可见。
有人对这种差异有什么想法吗?
//Holds message information.
System.Net.Mail.MailMessage mailMessage = new System.Net.Mail.MailMessage();
//Add basic information.
mailMessage.From = new System.Net.Mail.MailAddress(txtFrom.Text.Trim());
mailMessage.To.Add(txtTo.Text.Trim());
mailMessage.Subject = txtSubject.Text.Trim();
//Create two views, one text, one HTML.
System.Net.Mail.AlternateView plainTextView = System.Net.Mail.AlternateView.CreateAlternateViewFromString(txtBody.Text.Trim(), null, "text/plain");
System.Net.Mail.AlternateView htmlView = System.Net.Mail.AlternateView.CreateAlternateViewFromString(txtBody.Text.Trim() + "<image src=cid:HDIImage>", null, "text/html");
//Add image to HTML version
System.Net.Mail.LinkedResource imageResource = new System.Net.Mail.LinkedResource(fileImage.PostedFile.FileName, "image/jpg");
imageResource.ContentId = "HDIImage";
htmlView.LinkedResources.Add(imageResource);
//Add two views to message.
mailMessage.AlternateViews.Add(plainTextView);
mailMessage.AlternateViews.Add(htmlView);
//Send message
System.Net.Mail.SmtpClient smtpClient = new System.Net.Mail.SmtpClient();
smtpClient.Send(mailMessage);
try
{
MailMessage mail = new MailMessage();
mail.To.Add("to@gmail.com");
mail.From = new MailAddress("from@gmail.com");
mail.Subject = "Test with Image";
string Body = "<b>Welcome</b><br><BR>Online resource for .net articles.<BR><img alt=\"\" hspace=0 src=\"cid:imageId\" align=baseline border=0 >";
AlternateView htmlView = AlternateView.CreateAlternateViewFromString(Body, null, "text/html");
LinkedResource imagelink = new LinkedResource(Server.MapPath(".") + @"\codedigest.png", "image/png");
imagelink.ContentId = "imageId";
imagelink.TransferEncoding = System.Net.Mime.TransferEncoding.Base64;
htmlView.LinkedResources.Add(imagelink);
mail.AlternateViews.Add(htmlView);
SmtpClient smtp = new SmtpClient();
smtp.DeliveryMethod = SmtpDeliveryMethod.PickupDirectoryFromIis;
smtp.Send(mail);
}
catch (Exception ex)
{
Response.Write(ex.Message);
}
if (!string.IsNullOrEmpty(BodyImageFileFullName))
{
var leftImageLink = new LinkedResource(BodyImageFileFullName, "image/jpg")
{
ContentId = "ImageGM_left",
TransferEncoding = TransferEncoding.Base64
};
htmlView.LinkedResources.Add(leftImageLink);
}
//Holds message information.
System.Net.Mail.MailMessage mailMessage = new System.Net.Mail.MailMessage();
//Add basic information.
mailMessage.From = new System.Net.Mail.MailAddress(txtFrom.Text.Trim());
mailMessage.To.Add(txtTo.Text.Trim());
mailMessage.Subject = txtSubject.Text.Trim();
//Create two views, one text, one HTML.
System.Net.Mail.AlternateView plainTextView = System.Net.Mail.AlternateView.CreateAlternateViewFromString(txtBody.Text.Trim(), null, "text/plain");
System.Net.Mail.AlternateView htmlView = System.Net.Mail.AlternateView.CreateAlternateViewFromString(txtBody.Text.Trim() + "<image src=cid:HDIImage>", null, "text/html");
//Add image to HTML version
System.Net.Mail.LinkedResource imageResource = new System.Net.Mail.LinkedResource(fileImage.PostedFile.FileName);
imageResource.ContentId = "HDIImage";
htmlView.LinkedResources.Add(imageResource);
//Add two views to message.
mailMessage.AlternateViews.Add(plainTextView);
mailMessage.AlternateViews.Add(htmlView);
//Send message
System.Net.Mail.SmtpClient smtpClient = new System.Net.Mail.SmtpClient();
smtpClient.Send(mailMessage);
接收站点或邮件代理正在使用规则,部分基于发件人,来阻止图像。您会发现,您的结果会因发送到哪里而有所不同。您可以采取的措施取决于接收方 - 您可以联系他们或查看他们发布的政策,以了解您可以跳过哪些障碍以避免被阻止。