I might be a little late on this subject, but I'm using VS2008 to connect to a 4D database using ODBC.  Basically you have to install the ODBC driver from 4D.  There are different versions so you have to make sure you have the right one for the server to which you are connecting.

Next, you have to configure a DSN.  I have been reading that you don't need to do this with v11, but the one I'm using requires a DSN, so I have created a System DSN. 

Then you write code like this - bear in mind that this is bare bones code, so you'll need to beef it up with try/catch, etc...

using System.Data.Odbc;

public class blah

{
    private OdbcConnection _conn;
   

    private void MakeConnection()
    {

        _conn = new OdbcConnection("DSN=4D Connection;UID=USER;PWD=PASSWORD;");

        string sqlQuery = "SELECT * FROM BLAH WHERE THIS = 'THAT'";

        OdbcCommand odbcCmd = new OdbcCommand(sqlQuery, _conn);

        IDataReader dr = (IDataReader)odbcCmd.ExecuteReader();

        //hopefully, if everything is configured correctly your data will be in dr

    }

}

Hope that helps.  I know it's probably too late, but I thought I'd put in my two cents.