Casting Ado.net DataReader to IDataRecord giving strange result

Question

I have a query that I run against the database, and I can see that there is a record for 31/05/2013. When I run this query from C# with ADO.NET, and then use the following

Answer 1

There are two ways of iterating through a data-reader; one is to keep calling .Read(); the other is to treat it as an IEnumerable sequence of IDataRecord and foreach it; no matter which you choose you can only iterate the data once.

• the call to .Read() moves from the BOF to the first record, if one
  • the ToList() calls GetEnumerator() then MoveNext() in a loop, which immediately moves forward one position (so we've dropped the first record on the floor without processing it); at the end of the ToList() we have chewed through all the data
• so the outer .Read() will then report false (EOF)

Basically: the problem here is using two APIs that progress the position. Either use .Read(), or use the foreach API (.ToList()).

As a side note, since the column names match the member names you could also use "dapper" to do the heavy lifting:

var list = conn.Query(sql, args).ToList();