C#

public void CallingMethod()<br />
{<br />
    // Calling Process() method numerous times, aquiring numerous IAsyncResults<br />
<br />
    // Iterating over all IAyncResults aquired above and waiting for each WaitHandle.<br />
<br />
    // Ups, sometimes there are no error messages in the IAyncResult.AsyncState<br />
}<br />
<br />
public IAsyncResult Process()<br />
{<br />
    IAsyncResult asyncResult = myWebRequest.BeginGetResponse(RespCallback, myRequestState);<br />
    return asyncResult;<br />
}<br />
<br />
private void RespCallback(IAsyncResult asyncResult)<br />
{<br />
    try<br />
    {<br />
        resp = req.EndGetResponse(asyncResult);<br />
    }<br />
    catch (Exception ex)<br />
    {<br />
        string errorMessage = string.Format("host unreachable...");<br />
        // Before adding this error message the WebRequests WaitHandle is released!<br />
        ((MyRequestState)asyncResult.AsyncState).AddStatusMessage(errorMessage);<br />
    }<br />
}