How to send gridview content in email using ASP.NET?

<asp:GridView ID="GridView1" runat="server" CellPadding="4" ForeColor="#333333" GridLines="None">
    <RowStyle BackColor="#E3EAEB" />
    <FooterStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
    <PagerStyle BackColor="#666666" ForeColor="White" HorizontalAlign="Center" />
    <SelectedRowStyle BackColor="#C5BBAF" Font-Bold="True" ForeColor="#333333" />
    <HeaderStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
    <EditRowStyle BackColor="#7C6F57" />
    <AlternatingRowStyle BackColor="White" />
</asp:GridView>
<br />
<br />
<asp:Button ID="btnExcelSend" runat="server" Text="Send GridView Content attached Excel file in email"
    OnClick="btnExcelSend_Click" />  <br />
<asp:Button ID="btnGvEmail" runat="server" Text="Send GridView Content directly in email body"
    OnClick="btnGvEmail_Click" />
<br />

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

public partial class _Default : System.Web.UI.Page
{
    DataTable dt = new DataTable();
    DataRow dr;
    string frmid="fromid@gmail.com"; //change from id here 
    string frmpwd="frmpwd"; //change password here
    string toid = "toid@anydomain.com"; //change toid here
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            BindGrid();           
        }
    }
    void BindGrid()
    {
        dt.Columns.Add("Empno");
        dt.Columns.Add("Empname");
        dt.Columns.Add("Salary");
        dr = dt.NewRow();
        dr["Empno"] = "101";
        dr["Empname"] = "Ravindran";
        dr["Salary"] = "25000";
        dt.Rows.Add(dr);
        if (dt.Rows.Count > 0)
        {
            Session["source_table"] = dt;
            GridView1.DataSource = dt;
            GridView1.DataBind();
        }
    }   
    public override void VerifyRenderingInServerForm(Control control)
    {

    }
    protected void btnExcelSend_Click(object sender, EventArgs e)
    {
        //here i am sending gridview content as excel attachment in email
        ExcelEmail();
    }
    void ExcelEmail()
    {
        System.IO.StringWriter sw = new System.IO.StringWriter();
        System.Web.UI.HtmlTextWriter htw = new System.Web.UI.HtmlTextWriter(sw);
        GridView1.RenderControl(htw);
        string renderedGridView = sw.ToString();
        //write file in to disk
        System.IO.File.WriteAllText(Server.MapPath("temp.xls"), renderedGridView);
        try
        {
            MailMessage msg = new MailMessage(frmid, toid, "Test GridView Attachment", "Mail_Body");
            SmtpClient mailClient = new SmtpClient("smtp.gmail.com", 587);
            NetworkCredential NetCrd = new NetworkCredential(frmid,frmpwd);
            //Attach that excel sheet
            msg.Attachments.Add(new Attachment(Server.MapPath("temp.xls")));
            mailClient.UseDefaultCredentials = false;
            mailClient.Credentials = NetCrd;
            mailClient.EnableSsl = true;
            mailClient.DeliveryMethod = SmtpDeliveryMethod.Network;
            mailClient.Send(msg);
            msg.Dispose();
            //Delete that temp file after sent
            if (System.IO.File.Exists(Server.MapPath("temp.xls")))
            {
                System.IO.File.Delete(Server.MapPath("temp.xls"));
            }
        }
        catch (Exception ex)
        {
        }
    }
    protected void btnGvEmail_Click(object sender, EventArgs e)
    {
        //here i am sending gridview content directly as an email
        GvEmail();
    }
    void GvEmail()
    {
        System.IO.StringWriter sw = new System.IO.StringWriter();
        System.Web.UI.HtmlTextWriter htw = new System.Web.UI.HtmlTextWriter(sw);
        GridView1.RenderControl(htw);
        string renderedGridView = sw.ToString();      
        try
        {
            MailMessage msg = new MailMessage(frmid, toid, "Test GridView Content", renderedGridView);
            SmtpClient mailClient = new SmtpClient("smtp.gmail.com", 587);
            NetworkCredential NetCrd = new NetworkCredential(frmid, frmpwd);
            msg.IsBodyHtml = true;
            mailClient.UseDefaultCredentials = false;
            mailClient.Credentials = NetCrd;
            mailClient.EnableSsl = true;
            mailClient.DeliveryMethod = SmtpDeliveryMethod.Network;
            mailClient.Send(msg);
            msg.Dispose();           
        }
        catch (Exception ex)
        {
        }
    }
}