There is already an open DataReader associated with this Com

Question

how to solve There is already an open DataReader associated with this Command which must be closed first.error

Ramesh Palanivel · Answer

Try this, using (DbCommand cmd = new CommandBuilder().SetCommandText(string.Format(@"insert into wdccache values ('{0}' ,'{1}', '{2}','{3}')", ID, Exptime, filepath, Key)) .SetCommandType(CommandType.Text) .ToDbCommand()) { var reader = cmd.ExecuteReader() { while (reader.Read()) { if (DateTime.Compare(Exptime, DateTime.UtcNow) { wDCTableData = new WDCTableData { key = reader.GetValue ("Key"), Exptime = reader.GetValue ("ExpirationDate"), filepath = reader.GetValue ("Filepath") }; } } } }

Satish · Answer

Invalid attempt to read when no data is present. This error is getting

Satish · Answer

is this correct way read column data var cmd1 = new .Data.CommandBuilder().SetCommandText(string.Format("select * from wdccache where [Key] = '{0}'", Key)).SetCommandType(CommandType.Text).ToDbCommand(); using (var reader = cmd1.ExecuteReader()) { if (DateTime.Compare(Exptime, DateTime.UtcNow) { wDCTableData = new WDCTableData { key = reader["Key"].ToString(), Exptime = (DateTime)reader["ExpirationDate"], filepath = reader["Filepath"].ToString() }; }

Ramesh Palanivel · Answer

Hi Nageshwar, Just remove the Using in that "var reader" Method

Gnanavel Sekar · Answer

You need to close your reader connection. Note that while a DataReader is open, the Connection is in use exclusively by that DataReader. You cannot execute any commands for the Connection, including creating another DataReader, until the original DataReader is closed. Example: string queryString = "SELECT OrderID, CustomerID FROM dbo.Orders;"; using (SqlConnection connection = new SqlConnection(connectionString)) { SqlCommand command = new SqlCommand(queryString, connection); connection.Open(); SqlDataReader reader = command.ExecuteReader(); // Call Read before accessing data. while (reader.Read()) { Console.WriteLine(String.Format("{0}, {1}", reader[0], reader[1])); } // Call Close when done reading. reader.Close(); Refer More Links for your answer http://stackoverflow.com/questions/18475195/error-there-is-already-an-open-datareader-associated-with-this-command-which-mu http://stackoverflow.com/questions/6062192/there-is-already-an-open-datareader-associated-with-this-command-which-must-be-c https://www.codeproject.com/questions/616154/there-is-already-an-open-datareader-associated-wit http://stackoverflow.com/questions/6062192/there-is-already-an-open-datareader-associated-with-this-command-which-must-be-c

Satish · Answer

Is this correct var cmd = new Data.CommandBuilder().SetCommandText(string.Format(@"insert into wdccache values ('{0}' ,'{1}', '{2}','{3}')", ID, Exptime, filepath, Key)) .SetCommandType(CommandType.Text) .ToDbCommand(); var cmd1 = new Data.CommandBuilder().SetCommandText(string.Format("select * from wdccache")) .SetCommandType(CommandType.Text) .ToDbCommand(); using (var reader = cmd1.ExecuteReader()) { if (DateTime.Compare(Exptime, DateTime.UtcNow) { wDCTableData = new WDCTableData { key = reader.GetValue ("Key"), Exptime = reader.GetValue ("ExpirationDate"), filepath = reader.GetValue ("Filepath") }; }

Ramesh Palanivel · Answer

Hi Nageshwar, The issue is you are trying to execute your command in another using statement, change code like, DbDataReader reader = cmd.ExecuteReader() inside first using statement

Satish · Answer

Like this using (DbCommand cmd = new CommandBuilder().SetCommandText(string.Format(@"insert into wdccache values ('{0}' ,'{1}', '{2}','{3}')", ID, Exptime, filepath, Key)) .SetCommandType(CommandType.Text) .ToDbCommand()) { using (DbDataReader reader = cmd.ExecuteReader()) { while (reader.Read()) { if (DateTime.Compare(Exptime, DateTime.UtcNow) { wDCTableData = new WDCTableData { key = reader.GetValue ("Key"), Exptime = reader.GetValue ("ExpirationDate"), filepath = reader.GetValue ("Filepath") }; } } } }

Ramesh Palanivel · Answer

HI Nageshwar, Have you opened Datareader with in Datareader, for the reason you are getting this error, We cannot access the Datareader with in Datareader, try to close the first Data reader or post your solution file, I will help you

There is already an open DataReader associated with this Com

Answers (9)