protected void botaoLogin_Click(object sender, EventArgs e)
        {
            string nome = user.Text;
            string senha = senhaa.Text;
            Database bd = new Database();
            bd.conecta();


            int i = 0;
            MySqlCommand cmd = bd.bdConn.CreateCommand();
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = "select * from tb_usuario where nome_de_usuario='" + nome + "'and senha='" + senha + "'";
            cmd.ExecuteNonQuery();


            DataTable dt = new DataTable();
            MySqlDataAdapter da = new MySqlDataAdapter(cmd);
            da.Fill(dt);
            i = Convert.ToInt32(dt.Rows.Count.ToString());


            if (i == 0)
            {
                ScriptManager.RegisterStartupScript(this, GetType(), "showalert", "alert('Falha ao logar usuário.');", true);
            }
            else
            {
                ScriptManager.RegisterStartupScript(this, GetType(), "showalert", "alert('Usuário logado com sucesso.');", true);
                Server.Transfer("index.aspx?autor=" + nome);
            }