// Contains the delegate for the "read file" event that creates a stream to the external file
// and the delegate that registers with the "read complete" event to close the stream.  
public class ExternalFileHandler
{
    // the stream that will be used to read the file that contains the stored procedure
    FileStream _internalStream;
            
    // Delegate for the TdConnection.OpenFile event
    public void OnOpenFile(Object sender, TdSourceFileEventArgs eventArgs)
    {
        String FileName = eventArgs.FileName;
            
        // create a file stream
        _internalStream = new FileStream(FileName, FileMode.Open);
            
        // send the stream back to the Provider
        eventArgs.ExternalFileObject = _internalStream;
    }
             
    // Delegate for the TdConnection.CloseFile event
    public void OnCloseFile(Object sender, TdSourceFileEventArgs eventArgs)
    {
        _internalStream.Close();
    }
 }
            
            
public void CreateExternalProcedure(TdConnection cn)
{
    TdCommand cmd = cn.CreateCommand();
    cmd.CommandText = "CREATE PROCEDURE provider_sp(INOUT region VARCHAR(64)) " +
                      "LANGUAGE C NO SQL EXTERNAL NAME 'CS!provider_sp!c:\xsp.c!F!provider_sp' " +
                      "PARAMETER STYLE SQL";
            
            
    // create delegates for the OpenFile and CloseFile events
    ExternalFileHandler fh = new ExternalFileHandler();
    TdOpenFileEventHandler extFile = new TdOpenFileEventHandler(fh.OnOpenFile);
    TdCloseFileEventHandler extReadCompleted = new TdCloseFileEventHandler(fh.OnCloseFile);
            
    // The OpenFile event will be raised when the Teradata Database requests the source code of
    // the stored procedure. Registration for this event is required if executing a DDL that 
    // requires data to be read from a file that resides on the client machine.
    cn.OpenFile += extFile;
            
    // The CloseFile event will be raised after the Teradata Database has received all the 
    // source code for the stored procedure. Registering for this event is optional.
    cn.CloseFile += extReadCompleted;
            
    try
    {
        // read the results
        using (TdDataReader dr = cmd.ExecuteReader())
        {
            String result;
            while (dr.Read() == true)
            {
                result = dr.GetString(0);
                Console.WriteLine(result);
            }
        }
    }
    finally
    {
        // unregister the event handlers
        cn.OpenFile -= extFile;
        cn.CloseFile -= extReadCompleted;
    }
}