Invalid attempt to call FieldCount when reader is closed

Question

The error above occurs when I try to do a dataReader.Read on the data recieved from the database. I know there are two rows in there so it isnt because no data actually exis

Answer 1

Your code, as displayed is fine. I've taken it into a test project, and it works. It's not immediately clear why you get this message with the code shown above. Here are some debugging tips/suggestions. I hope they're valuable for you.

• Create a breakpoint on the while (dataReader.Read()). Before it enters its codeblock, enter this in your Immediate or Watch Window: dataReader.HasRows. That should evaluate to true.

• While stopped on that Read(), open your Locals window to inspect all the properties of dataReader. Ensure that the FieldCount is what you expect from your SELECT statement.

• When stepping into this Read() iteration, does a student object get created at all? What's the value of dataReader["StructureID"] and all others in the Immediate Window?

It's not the CommandBehavior.CloseConnection causing the problem. That simply tells the connection to also close itself when you close the datareader.