asynchronous design pattern and event

[marian.kovac]

Hi, I have this simple sample code:

class SearchRange
{
static int m = 0;
static void Main(string[] args)
{
Discover discover = new Discover();

// Add discovered device handler
discover.Discov erUpdate += DiscoveredDevic eCallback;

// Add progress handler
discover.Progre ssUpdate += ProgressCallbac k;

Console.WriteLi ne("Discovered devices:");

// Start searching for devices
IAsyncResult ar = discover.BeginS earchRange("193 .93.73.180",
"193.93.73.190" ,
1000, CompletedCallba ck, null);

discover.EndSea rchRange(ar);

Result result;
DiscoveredDevic e discoveredDevic e = discover.EndSea rchAddress(ar,
out result);

Console.WriteLi ne("\nResult: {0}", result.Status);
if (discoveredDevi ce != null)
Console.WriteLi ne("Discovered device: {0}\n",
discoveredDevic e.Name);
}

private static void DiscoveredDevic eCallback(objec t sender,
DiscoverEventAr gs e)
{
DiscoveredDevic e device = e.DiscoveredDev ice;
Console.WriteLi ne("{0} {1} {2}", device.SerialNu mber,
device.IPAddres s, device.Name);
}

private static void ProgressCallbac k(object sender, ProgressEventAr gs
e)
{
Console.WriteLi ne("Progress: {0}%", e.Progress);
Thread.Sleep(30 0);
}

private static void CompletedCallba ck(IAsyncResult ar)
{
Console.WriteLi ne("Completed Callback!\n");
}
}

class Discover is implemented as asynchronous design pattern
(asynchronous methods are BeginSearchAddr ess, EndSearchAddres s).
ProgressCallbac k is callback for event ProgressUpdate. That code has
the correct progress output (e.g. 20% 30% ... 100%) if
Thread.Sleep(30 0) is commented else program get bad progress output
(e.g. 20% 30% ... 100% 60%). I know that CompletedCallba ck is called
when the request (BeginSearchAdd ress) is completed, and the EndRequest
call will wait until the request is complete and return the result.
Those are know things. And what event? Does the event [event callback]
need in the class implemented as asynchronous design pattern special
handling of the itself code? Where can I found information about this
problem? Thanks and best regards

Marian.