getting invalid identifer error when fetching the data from

Question

OracleConnection conn = new OracleConnection(oradb);

OracleCommand cmd = new OracleCommand();

conn.Open();

cmd.Connection = conn;

cmd.CommandType = CommandType.Text;

cmd.BindByName = true;

//cmd.Parameters.Add(new OracleParameter("BranchID",BranchId));

OracleParameter transdate1= new OracleParameter();

transdate1.OracleDbType = OracleDbType.Date;

transdate1.Value = TextBox1.Text;

cmd.Parameters.Add(transdate1);

OracleParameter transdate2 = new OracleParameter();

transdate2.OracleDbType = OracleDbType.Date;

transdate2.Value = TextBox2.Text;

cmd.Parameters.Add(transdate2);

cmd.CommandText = "select * from cust_details where transdate between transdate1 and transdate2";

OracleDataAdapter od = new OracleDataAdapter(cmd);

DataSet ds = new DataSet();

od.Fill(ds);

GridView1.DataSource = ds;

GridView1.DataBind();

//Response.Write("Connected to Oracle" + conn.ServerVersion);

// Close and Dispose OracleConnection object

lblDisplay.Text = "connected";

conn.Close();

conn.Dispose();