<%@ Page Language="C#" MasterPageFile="~/Admin/TarasAdmin.master" AutoEventWireup="true" CodeFile="Mail.aspx.cs" Inherits="Admin_Default2" EnableEventValidation="false" ValidateRequest="false" ViewStateEncryptionMode="Never"%>
<%@ Register TagPrefix="FTB" Namespace="FreeTextBoxControls" Assembly="FreeTextBox" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
    <style type="text/css">
        .style1
        {
            width: 100%;
        }
    </style>
     <script language="javascript">
function check_uncheck(Val)
{
  var ValChecked = Val.checked;
  var ValId = Val.id;
  var frm = document.forms[0];
  // Loop through all elements
  for (i = 0; i < frm.length; i++)
  {
    // Look for Header Template's Checkbox
    //As we have not other control other than checkbox we just check following statement
    if (this != null)
    {
      if (ValId.indexOf('CheckAll') !=  - 1)
      {
        // Check if main checkbox is checked,
        // then select or deselect datagrid checkboxes
        if (ValChecked)
          frm.elements[i].checked = true;
        else
          frm.elements[i].checked = false;
      }
      else if (ValId.indexOf('deleteRec') !=  - 1)
      {
        // Check if any of the checkboxes are not checked, and then uncheck top select all checkbox
        if (frm.elements[i].checked == false)
          frm.elements[1].checked = false;
      }
    } // if
  } // for
} // funct
</script><script type="text/javascript">
function confirmMsg(frm)
{
  // loop through all elements
  for (i = 0; i < frm.length; i++)
  {
    // Look for our checkboxes only
    if (frm.elements[i].name.indexOf("deleteRec") !=  - 1)
    {
      // If any are checked then confirm alert, otherwise nothing happens
      if (frm.elements[i].checked)
      return confirm('Are you sure you want to delete your selection(s)?')
    }
  }
}
</script>


</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">


    <table class="style1">
        <tr>
            <td>
                 </td>
            <td>
                <asp:GridView ID="gvUsers" runat="server" AllowSorting="True"
                    AutoGenerateColumns="False">
                    <Columns>
                        <asp:TemplateField>
                            <HeaderTemplate>
                                <asp:CheckBox ID="CheckAll" runat="server"
                                    onclick="return check_uncheck (this );" />
                                Select AllSelect All
                            </HeaderTemplate>
                            <ItemTemplate>
                                <asp:Label ID="lblMobile" runat="server"
                                    Text='<%# DataBinder.Eval (Container.DataItem, "Email") %>' Visible="false" />
                                <asp:Label ID="RId" runat="server"
                                    Text='<%# DataBinder.Eval (Container.DataItem, "RId") %>' Visible="false" />
                                <asp:CheckBox ID="deleteRec" runat="server"
                                    onclick="return check_uncheck (this );" Text='<%# Eval("Email") %>' />
                            </ItemTemplate>
                        </asp:TemplateField>
                        <asp:BoundField DataField="RId" HeaderText="RId" InsertVisible="False"
                            ReadOnly="True" SortExpression="RId" />
                        <asp:BoundField DataField="Mobile" HeaderText="Mobile"
                            SortExpression="Mobile" />
                        <asp:TemplateField>
                            <ItemTemplate>
                                <asp:HyperLink ID="HyperLink1" runat="server"
                                    NavigateUrl='<%#"UserDetails.aspx?RId=" + Eval("RId")%>'
                                    Text='<%# Bind("Name") %>'></asp:HyperLink>
                            </ItemTemplate>
                        </asp:TemplateField>
                        <asp:BoundField DataField="Mobile" HeaderText="MobileNumber"
                            SortExpression="Mobile" />
                        <asp:BoundField DataField="DOB" HeaderText="DOB" SortExpression="DOB" />
                    </Columns>
                    <EmptyDataTemplate>
                        No data found
                    </EmptyDataTemplate>
                </asp:GridView>
                                                </td>
            <td>
                 </td>
        </tr>
        <tr>
            <td>
                Subject</td>
            <td>
                <asp:TextBox ID="txtSubject" runat="server"></asp:TextBox>
            </td>
            <td>
                 </td>
        </tr>
        <tr>
            <td>
                Mail</td>
            <td>
                <FTB:FreeTextBox ID="txtBody" runat="server"></FTB:FreeTextBox>
                

            </td>
            <td>
                 </td>
        </tr>
        <tr>
            <td>
                 </td>
            <td>
                <asp:Button ID="btnSend" runat="server" Text="Send" onclick="btnSend_Click" />
            </td>
            <td>
                 </td>
        </tr>
    </table>


</asp:Content>

.CS code:

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;
using System.Net.Mail;
using System.Text;

public partial class Admin_Default2 : System.Web.UI.Page
{
    string s;
    string sql;
    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["TarasConnectionString"].ConnectionString);
    protected void Page_Load(object sender, EventArgs e)
    {
        try
        {
            sql = "Select * from Users where Country='IN'";

            con.Open();
            SqlDataAdapter da = new SqlDataAdapter(sql, con);
            DataTable dt = new DataTable();

            DataSet ds = new DataSet();

            da.Fill(ds);
            da.Fill(dt);
            gvUsers.DataSource = ds;

            gvUsers.DataBind();
            con.Close();


        }
        catch
        {

        }
    }
    protected void btnSend_Click(object sender, EventArgs e)
    {
       
            string gvIDs = "";
            bool chkBox = false;
            //'Navigate through each row in the GridView for checkbox items
            foreach (GridViewRow gv in gvUsers.Rows)
            {
                CheckBox deleteChkBxItem = (CheckBox)gv.FindControl("deleteRec");
                if (deleteChkBxItem.Checked)
                {
                    chkBox = true;
                    // Concatenate GridView items with comma for SQL Delete
                    gvIDs += ((Label)gv.FindControl("lblMobile")).Text.ToString() + ",";
                }
            }
            Response.Write(gvIDs.Substring(0, gvIDs.LastIndexOf(",")));
            s = gvIDs.Substring(0, gvIDs.LastIndexOf(","));
            AlternateView View = null;
            LinkedResource resource = null;
            SmtpClient client = null;
            StringBuilder msgText = new StringBuilder();


            
            MailMessage msg = new MailMessage("stanly@stanly.com", s);
            msg.Body = txtBody.Text;
            msg.Subject = "Welcome to TarasJewellery.com";
            // msg.From = new MailAddress(email, "Taras Jewellery");
            msg.IsBodyHtml = true;

            View = AlternateView.CreateAlternateViewFromString(msgText.ToString(),
                                                    null, "text/html");
           




           
            SmtpClient smtpClient = new SmtpClient();
            smtpClient.Host = "relay-hosting.secureserver.net";
            smtpClient.Credentials = new System.Net.NetworkCredential("stanly@stanly.com", "stanly");
      
            smtpClient.Send(msg);
       

    }
}