DropDownList dropdownlist1 = (DropDownList)GridView1.Rows[e.RowIndex].FindControl("dropdownlist1");

private void Grid()
    {
        SqlConnection cn = new SqlConnection("Data Source=ANCYCHACKO-TOSH;Initial Catalog=tallysoftware;Integrated Security=True");

        SqlCommand cmd = new SqlCommand();
        DataTable dataTable;

        dataTable = new DataTable();

        cmd.Connection = cn;

        SqlDataAdapter da = new SqlDataAdapter("select * from Sheet1$ ", cn);

        System.Data.DataSet ds = new System.Data.DataSet();

        da.Fill(ds);

        if (ds != null && ds.Tables.Count > 0 && ds.Tables[0].Rows.Count > 0)
        {

            GridView1.DataSource = ds.Tables[0];
            GridView1.DataSource = ds;
            GridView1.DataBind();
            cn.Close();
        }
    }
    protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
    {
        GridView1.EditIndex = e.NewEditIndex;
        Grid();
    }
    protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
    {
        e.Cancel = true;
        GridView1.EditIndex = -1;
        Grid();
    }


    protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
    {

    }
    protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
    {
        GridView1.PageIndex = e.NewPageIndex;
        Grid();
    }
    protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["tallysoftwareConnectionString4"].ConnectionString);
        SqlCommand cmd = new SqlCommand();
        cn.Open();
        GridViewRow row = GridView1.Rows[e.RowIndex];
        DropDownList dropdownlist1 = (DropDownList)GridView1.Rows[e.RowIndex].FindControl("dropdownlist1");
        TextBox txtEcollected = (TextBox)row.FindControl("txtEcollected");
        TextBox txtEplan = (TextBox)row.FindControl("txtEplan");
        TextBox txtEacoll = (TextBox)row.FindControl("txtEacoll");
        DropDownList dropdownlist2 = (DropDownList)GridView1.Rows[e.RowIndex].FindControl("dropdownlist2");
        TextBox txtEre = (TextBox)row.FindControl("txtEre");
        TextBox txtEdescrptn = (TextBox)row.FindControl("txtEdescrptn");
        //int Id = Int32.Parse(GridView1.DataKeys[e.RowIndex].Value.ToString());
        string se_name = dropdownlist1.SelectedItem.Text;
        string collected_date = txtEcollected.Text;
        string amount_plan = txtEplan.Text;
        string amount_collected = txtEacoll.Text;
        string status_ar = dropdownlist2.SelectedItem.Text;
        string remark = txtEre.Text;
        string description = txtEdescrptn.Text;
        Label lblid = (Label)row.FindControl("Label3");
        // string id = GridView1.DataKeys[e.RowIndex].Value.ToString();
        int id = Convert.ToInt32(lblid.Text);
        cmd.CommandText = "UPDATE Sheet1$ SET se_name='" + dropdownlist1.SelectedItem.Text + "' ,collected_date ='" + txtEcollected.Text + "',amount_plan ='" + txtEplan.Text + "',amount_collected ='" + txtEacoll.Text + "',status_ar ='" + dropdownlist2.SelectedItem.Text + "',remark='" + txtEre.Text + "',description='" + txtEdescrptn.Text + "' WHERE id=" + id + "";
        cmd.Connection = cn;
        cmd.ExecuteNonQuery();

        GridView1.EditIndex = -1;

        Grid();
        cn.Close();


    }
    protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["tallysoftwareConnectionString4"].ConnectionString);
        SqlCommand cmd = new SqlCommand();

        cmd.Connection = cn;
        cn.Open();
        GridViewRow row = GridView1.Rows[e.RowIndex];
        Label lblid = (Label)row.FindControl("Label3");
        // string id = GridView1.DataKeys[e.RowIndex].Value.ToString();
        int id = Convert.ToInt32(lblid.Text);
        //int Id = Int32.Parse(GridView1.DataKeys[e.RowIndex].Value.ToString());
        cmd.CommandText = "DELETE FROM Sheet1$ WHERE id='" + id + "' ";

        cmd.ExecuteNonQuery();
        cn.Close();
        Grid();
    }
}