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public void update(object sender, GridViewUpdateEventArgs e)
        {
            SqlConnection conn = new SqlConnection(str_con);
            conn.Open();
            SqlCommand cmd1 = new SqlCommand("UpdateInfo", conn);
            cmd1.CommandType = CommandType.StoredProcedure;
            cmd1.Parameters.Add("@s_name", SqlDbType.VarChar).Value = (gv1.Rows[e.RowIndex].Cells[1].Text);
            cmd1.Parameters.Add("@s_phone", SqlDbType.Int).Value = Convert.ToInt32(gv1.Rows[e.RowIndex].Cells[2].Text);//<-----error shows here
            cmd1.Parameters.Add("@s_degree", SqlDbType.VarChar).Value = (gv1.Rows[e.RowIndex].Cells[3].Text);
            cmd1.Parameters.Add("@s_id", SqlDbType.Int).Value = Convert.ToInt32(gv1.Rows[e.RowIndex].Cells[4].Text);
            cmd1.ExecuteNonQuery();
            gv1.EditIndex = -1;
            BindData();
            conn.Close();
        }

set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON
GO
ALTER procedure [dbo].[UpdateInfo]
(
	@s_id int,
	@s_name varchar(300),
	@s_phone int,
	@s_degree varchar(300)
)
as
begin
update info set s_name=@s_name, s_phone=@s_phone, s_degree=@s_degree where s_id=@s_id
end