Unable to connect to AS400 in C#

I am trying to connect to an AS400 database from C# code and cannot find what I am doing wrong.
This is the error that I get (thrown by the conn.Open()):
"Non-NULL controlling IUnknown was specified, and either the requested interface was not IUnknown, or the provider does not support COM aggregation."

Here is the body of my code:
String connectionString = "Provider=IBMDA400;Data Source=myAS400;User ID=myUser;Password=myPassword;";
System.Data.OleDb.OleDbConnection conn = new System.Data.OleDb.OleDbConnection(connectionString);
conn.Open(); <--- this is where it throws an Exception.
conn.Close();

Here is what I don't understand -- I am able to create a connection to the AS400 through the 'Server Explorer' with these settings:
Data Source: .NET Framework Data Provider for OLE DB
OLE DB Provider: IBM AS400 OLE DB Provider
Server: myAS400
User: myUser
Pass: myPassword

Any ideas what my problem is - and how I might be able to create that same connection within my C# code.

Thanks!

1 Reply

Know the answer? Post it — somebody with the same question will find it here.

Brian19y ago
Here is the solution found:
From Windows:
Go into Admin Tools > Data Sources (ODBC)
Select the System DSN Tab and Add a new System Data Source
Select the ODBC driver used to connect to the AS400
Give it a Data Source Name, AS400 System Name, Library List (*USRLIBL)

From a c# program:
using System.Data.Odbc;

String connectionString = "Dsn=myAS400dsn;uid=myUser;pwd=myPassword";
OdbcConnection conn = new OdbcConnection(connectionString);
conn.Open();

string queryString = "SELECT * FROM myLibrary.myTable";
OdbcCommand command = new OdbcCommand(queryString, conn);
OdbcDataReader rs = command.ExecuteReader();

while (rs.Read())
{
Console.WriteLine(rs.GetString(0));
}

conn.Close();