Hi
I get a InvalidOperationException message when I click button2 at this line
of code textBox1.Text = whoIs1.EndLookup( asyncResult );
Should I now be implementing the BackgroundWorker Class now?
Many thanks
Dion
private void button2_Click(object sender, System.EventArgs e)
{
whoIs1.WhoIsServer = comboBox1.Text;
whoIs1.Query = textBox3.Text;
whoIs1.Port = Convert.ToInt32(textBox4.Text);
// using callback
whoIs1.BeginLookup(textBox3.Text, new AsyncCallback( OurCallback ), null);
MessageBox.Show("Doing other stuff." + "\r\n" ,"Viascape WhoIs",
MessageBoxButtons.OK, MessageBoxIcon.Error);
}
private void OurCallback ( IAsyncResult asyncResult )
{
textBox1.Text = whoIs1.EndLookup( asyncResult );
}
--------------------------------------------
Whois Class
/// <summary>
/// Begins an asynchronous lookup operation for WhoIs information.
/// </summary>
/// <param name="query">A string containing the WhoIs host name to
query.</param>
/// <param name="callback">
/// The callback method to be called when the asynchronous operation is
completed.
/// </param>
/// <param name="state">The state object.</param>
/// <returns>
/// An <see cref="IAsyncResult"/> instance that references the asynchronous
request.
/// </returns>
/// <remarks>
/// The BeginLookup method starts an asynchronous request for WhoIs host
information.
/// The asynchronous callback method uses the <see cref="EndLookup"/> method
to return the
/// actual WhoIs information.
/// </remarks>
public IAsyncResult BeginLookup(string query, System.AsyncCallback callback,
object state )
{
// Create an instance of a delegate that wraps Lookup method
LookupDelegate dlgt = new LookupDelegate (this.Lookup);
// Initiate the Asynchronous call passing in the callback delegate
// and the delegate object used to initiate the call
return dlgt.BeginInvoke(query, callback, state);
//IAsyncResult asyncResult = dlgt.BeginInvoke(query, callback, state);
//return asyncResult;
}
/// <summary>
/// Ends an asynchronous request for WhoIs information.
/// </summary>
/// <param name="asyncResult">The pending request for WhoIs
information.</param>
/// <returns>The results of the asynchronous lookup containing the WhoIs
information.</returns>
/// <remarks>
/// The <b>EndLookup</b> method completes an asynchronous request for WhoIs
information that was
/// started with a call to <see cref="BeginLookup"/>.
/// </remarks>
public string EndLookup(IAsyncResult asyncResult)
{
// Extract the delegate from the AsyncResult
LookupDelegate dlgt =
(LookupDelegate)((AsyncResult)asyncResult).AsyncDe legate;
//AsyncResult aResult = (AsyncResult)asyncResult;
//LookupDelegate dlgt = (LookupDelegate)aResult.AsyncDelegate;
// Retrieve the results of the asynchronous call
return dlgt.EndInvoke(asyncResult);
}
