There is already an open DataReader associated with this Connection which must be closed first?

Question

I am facing the DataReader open connection issue in ASP.NET c# While Reading the records from MySQL database. I do not know how at first time of execution of datareader it showing me open connection.

The error as below at DAL

MySqlDataReader reader = myCommand.ExecuteReader();

There is already an open DataReader associated with this Connection which must be closed first

Sample Code

// BAL function call the DAL function 

MainFunction()
{
...
...
  using (MySqlDataReader reader = clsDAL.GetALL(SqlQuery, Parms))
            {
                while (reader.Read())
                {
                    clsVitalsDisplay obj = new clsVitalsDisplay();

                    obj.BySessionId = Convert.ToInt32(reader["BySessionId"].ToString());
                    obj.ByDevSessionId_LifeTouchHeartRate = Convert.ToInt32(reader["ByDevSessionId_LifeTouchHeartRate"].ToString());
                    obj.HumanReadableDeviceId_LifeTouch = reader["HumanReadableDeviceId_LifeTouch"].ToString();

                    listLifetouchHeartRate.Add(obj);
                }
            }
}

// Getting the Error while Read the details from database in DAL (Data Access Layer) class at MySqlDataReader reader = myCommand.ExecuteReader();

 public static MySqlDataReader GetALL(String _query, MySqlParameter[] sqlParameter)
    {
        MySqlCommand myCommand = new MySqlCommand();

        try
        {
            myCommand.Connection = OpenConnection();
            myCommand.CommandText = _query;
            myCommand.Parameters.AddRange(sqlParameter);
            myAdapter.SelectCommand = myCommand;
//Face the error at below line
            MySqlDataReader reader = myCommand.ExecuteReader();
            myCommand.Dispose();
            return reader;
        }
        catch (MySqlException ex)
        {
            ErrorLog.ErrorLog.Log_Err("", ex, Global.gUserId.ToString());
            return null;
        }
        finally
        {

        }
    }

Answer 1

I have fixed this issue by closing the already opening adatabase connection if open as below. Afterthat its working fine.

public static MySqlDataReader GetALL(String _query, MySqlParameter[] sqlParameter)
    {
        MySqlCommand myCommand = new MySqlCommand();

        try
        {
             if (con.State == ConnectionState.Open)
                {
                con.Close();
                }

            myCommand.Connection = OpenConnection();
            myCommand.CommandText = _query;
            myCommand.Parameters.AddRange(sqlParameter);
            myAdapter.SelectCommand = myCommand;

            MySqlDataReader reader = myCommand.ExecuteReader();
            myCommand.Dispose();
            return reader;
        }
        catch (MySqlException ex)
        {
            ErrorLog.ErrorLog.Log_Err("", ex, Global.gUserId.ToString());
            return null;
        }
        finally
        {

        }
    }