How to use Parallel.ForEach with Grid View in ASP.NET - asp.net

Question

I had created an application to send bulk mail but my application is taking too much time to send all the emails. This was my code:
foreach (GridViewRow grow in GridView1.Rows)
{
string Emails = grow.Cells[0].Text.Trim();
string file = Server.MapPath("~/Mail.html");
string mailbody = System.IO.File.ReadAllText(file);
string to = Emails;
string from = "xyz#gmail.com";
MailMessage msg = new MailMessage(from, to);
msg.Subject = "Auto Response Email";
msg.Body = mailbody;
msg.BodyEncoding = Encoding.UTF8;
msg.IsBodyHtml = true;
SmtpClient client = new SmtpClient("smtp.live.com", 25);
client.UseDefaultCredentials = false;
System.Net.NetworkCredential basicCredential = new System.Net.NetworkCredential("xyz#gmail.com", "password");
client.EnableSsl = true;
client.UseDefaultCredentials = true;
client.Credentials = basicCredential;
try
{
client.Send(msg);
cnfrm.Text = "Email Sended Successfully";
}
catch (Exception ex)
{
Response.Write(ex.Message);
}
}
So for it's solution I tied to use the Parallel.ForEach but I am finding myself unable to use it with GridView.
Parallel.ForEach(GridView1.Rows, GridViewRow =>
{
string Emails = grow.Cells[0].Text.Trim();
string file = Server.MapPath("~/Mail.html");
string mailbody = System.IO.File.ReadAllText(file);
string to = Emails;
string from = "xyz#gmail.com";
MailMessage msg = new MailMessage(from, to);
msg.Subject = "Auto Response Email";
msg.Body = mailbody;
msg.BodyEncoding = Encoding.UTF8;
msg.IsBodyHtml = true;
SmtpClient client = new SmtpClient("smtp.live.com", 25);
client.UseDefaultCredentials = false;
System.Net.NetworkCredential basicCredential = new System.Net.NetworkCredential("xyz689#gmail.com", "password");
client.EnableSsl = true;
client.UseDefaultCredentials = true;
client.Credentials = basicCredential;
try
{
client.Send(msg);
cnfrm.Text = "Email Sended Successfully";
}
catch (Exception ex)
{
Response.Write(ex.Message);
}
});
Could anyone tell me how I can use it!!

Answer 1

I don't think you can access the Gridview rows like that with multiple threads, extract the text in your main thread then use foreach. Also take a look at Partitioner to use with ForEach
Here's an example of how it might look:
var emailtext = new List<string>()
foreach (GridViewRow grow in GridView1.Rows)
{
emailtext.Add(grow.Cells[0].Text.Trim());
}
//split and load balance the List
Partitioner<string> partitioner = Partitioner.Create(emailtext, true);
Parallel.ForEach(partitioner, mailtext =>
{
//your email sending code here
//NB: 'mailtext' is your string to send
}
Note: Most mail providers limit the number of emails you send per session or per hour, so you may need to consider this in your application.