protected void btnSubmit_Click(object sender, EventArgs e)
{
try
{
MailAddress SendFrom = new MailAddress(txtFrom.Text);
MailAddress SendTo = new MailAddress(txtTo.Text);

MailMessage MyMessage = new MailMessage(SendFrom, SendTo);

MyMessage.Subject = txtSubject.Text;
MyMessage.Body = txtBody.Text;

Attachment attachFile = new Attachment(txtAttachmentPath.Text);
MyMessage.Attachments.Add(attachFile);

SmtpClient emailClient = new SmtpClient(txtSMTPServer.Text);
emailClient.Send(MyMessage);

litStatus.Text = "Message Sent";
}
catch (Exception ex)
{
litStatus.Text=ex.ToString();
}
}

Imports System.Data.SqlClient
Imports System.Net.Mail
Imports System.NetPublic Class Form1    
Public Shared ConnectionString As String = ""    
Public conn As New SqlConnection    
Public ServerName As String    
Public database As String = ""    
Public Shared sysdate As Date    
Dim selcmd As SqlCommand   
Dim da As SqlDataAdapter    
Dim ds As New DataSet()    
Dim dr As DataRow  
  
Private Sub btnSendMails_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSendMails.Click       
 If conn.State = 1 Then conn.Close()        
conn.ConnectionString = ("Server=yourservername;Database=yourdatabasename;Integrated Security=True;Asynchronous Processing=True;")       
 conn.Open()       
 'MsgBox("connected")    
    sysdate = System.DateTime.Now()   
     Dim dt As String = sysdate.Day  
      selcmd = New SqlCommand("select * from yourtablename where Day (yourcolumnname) like '" & dt & "'", conn)
        da = New SqlDataAdapter()       
 da.SelectCommand = selcmd       
 da.Fill(ds, "yourtablename")        
DataGridView1.DataSource = ds.Tables("yourtablename")
        For Each dr In ds.Tables("yourtablename").Rows    
        Dim ToAddress As String = dr("EmpEmailAddress")                      
  Dim FromAddress As String = "yourmailadress@gmail.com"      
      Dim Subject As String = "Put some message here"          
  Dim Body As String = "Put some message here"
            
Dim mail As System.Net.Mail.MailMessage = New System.Net.Mail.MailMessage()       
  mail.To.Add(ToAddress)                
  mail.From = New MailAddress(FromAddress) 
  mail.Subject = Subject          
  mail.Body = Body          
  mail.Priority = System.Net.Mail.MailPriority.High   
Dim client As SmtpClient = New SmtpClient("yourhostname", "port")    
  client.Credentials = CredentialCache.DefaultNetworkCredentials     
  client.Send(mail)      
  Next   
 End Sub
End Class

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

namespace WindowsFormsApplication3
{
   
    public partial class Form1 : Form
    {
        SqlConnection sqlcon = new SqlConnection(@"Server=RAVI\SQLEXPRESS;database=test;uid=xxxx;pwd=yyyy;");
        SqlCommand sqlcmd = new SqlCommand();
        SqlDataAdapter da;
        DataTable dt = new DataTable();

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            sendMail("yourid@anydomain.com");
        }
        void sendMail(String tomailid)
        {
            try
            {
                MailMessage msg = new MailMessage("fromid@gmail.com", tomailid, "subjectofmail", "Mail_Body");
                SmtpClient mailClient = new SmtpClient("smtp.gmail.com", 587);
                NetworkCredential NetCrd = new NetworkCredential("fromid@gmail.com", "fromidpassword");
                mailClient.UseDefaultCredentials = false;
                mailClient.Credentials = NetCrd;
                mailClient.EnableSsl = true;
                mailClient.DeliveryMethod = SmtpDeliveryMethod.Network;
                mailClient.Send(msg);
            }
            catch (Exception ex)
            {
            }        
        }
    }
}