SqlException: Is there an open DataReader assigned to this Command?

Question

.NET

There is a library. It implements the methods of sampling, insertion, and so on.
In client application I do insert, and then select. All without problems.
Further, no matter what request I make, it throws an InvalidOperationException with the message "There is an open DataReader assigned to this Command that needs to be closed first."

Answer 1

Just DataReader.Close() didn't.

Answer 2

Maybe someone will come in handy, if a DataAdapter is used, then a copy of it must be created for each individual thread