.net send mail on specific time in windows form

To send an email at a specific time in a Windows Forms application using.NET, you can use the System.Threading.Timer class to schedule a timer that will trigger a method to send the email at the desired time.

Here's an example of how you can do this:

using System;
using System.Net.Mail;
using System.Threading;

public partial class Form1 : Form
{
    private Timer _timer;

    public Form1()
    {
        InitializeComponent();
    }

    private void SendEmail()
    {
        // Create a new MailMessage object
        MailMessage mail = new MailMessage();

        // Set the sender and recipient
        mail.From = new MailAddress("[email protected]");
        mail.To.Add("[email protected]");

        // Set the subject and body
        mail.Subject = "Test email";
        mail.Body = "This is a test email";

        // Create a new SmtpClient object
        SmtpClient client = new SmtpClient();

        // Set the SMTP server and port
        client.Host = "smtp.example.com";
        client.Port = 587;

        // Send the email
        client.Send(mail);
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        // Set the timer to trigger at 8:00 AM every day
        _timer = new Timer(new TimerCallback(SendEmail), null, DateTime.Now.AddDays(1).AddHours(8), TimeSpan.FromDays(1));
    }
}

In this example, the SendEmail method is called every day at 8:00 AM using the Timer class. The TimerCallback delegate is used to specify the method to be called when the timer triggers.

You can adjust the timer settings to send the email at a different time or frequency by modifying the Timer constructor parameters. For example, to send the email every hour, you can use the following code:

_timer = new Timer(new TimerCallback(SendEmail), null, DateTime.Now.AddHours(1), TimeSpan.FromHours(1));

Make sure to add the necessary using statements and references to the System.Net.Mail and System.Threading namespaces to use the MailMessage and SmtpClient classes.

Also, you can use System.Timers.Timer instead of System.Threading.Timer if you are targeting.NET Framework 4.5 or later.

You can also use Task and TaskScheduler to send the email at a specific time, here is an example:

private async void Form1_Load(object sender, EventArgs e)
{
    await Task.DelayUntil(DateTime.Now.AddDays(1).AddHours(8));
    SendEmail();
}

This will send the email at 8:00 AM every day, but it will not run in the background, it will block the UI thread until the email is sent.

Please note that the above examples are just a demonstration of how to send an email at a specific time, you should adjust the code to fit your specific requirements and also make sure to handle any exceptions that may occur during the email sending process.