Using a text listener to log messages

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Here is a very simple way to log information from your program. It works by setting up a "listener" that will intercept any trace.write command and send them to the filestream that you open. I use this method to write diagnostic messages.

//
// Start.prg
//
#USING System.io
#USING System.Diagnostics
FUNCTION Start() AS VOID
    LOCAL objTraceListener AS TextWriterTraceListener
    LOCAL XferLog          AS FileStream
    LOCAL cFile            AS STRING
 
    cFile := "c:\test.log"
 
    // create the log file
    XferLog := 
System.IO.FileStream{System.IO.Path.Combine(System.Environment.CurrentDirectory, 
cFile), System.IO.FileMode.Create}
    objTraceListener := System.Diagnostics.TextWriterTraceListener{XferLog}
    System.Diagnostics.Trace.Listeners:Add(objTraceListener)
 
    Trace.WriteLine("Starting Log")
    Trace.WriteLine("This is a test")
    Trace.WriteLine("Leaving Log File")
 
    // close our log file now that we are done
    IF (XferLog != NULL)
       System.Diagnostics.Trace.Flush()
       XferLog:Close()
       System.Diagnostics.Trace.Listeners:Remove(objTraceListener)
    ENDIF
 
    RETURN