/// <summary>
/// Starts the user interface that prompts a user for a certificate.
/// </summary>
/// <param name="iClientChannel">The client channel.</param>
/// <param name="callback">The callback object.</param>
/// <param name="state">Any state data.</param>
/// <returns>The System.IAsyncResult to use to call back when processing has completed.</returns>
public IAsyncResult BeginDisplayInitializationUI(IClientChannel iClientChannel, AsyncCallback callback, object state)
{
// There are three ways of coordinating asynchronous activity. The WCF channels appear to ignore all of them. This
// asynchronous interface appears to be here for future deveopment because it currently doesn't work. A dummy
// IAsyncResult is created here that makes it appear that the User Interface was handled immediately. The real work is
// done when the synchronous 'End' method is called.
ClientChannelResult clientChannelResult = new ClientChannelResult();
clientChannelResult.IClientChannel = iClientChannel;
return(clientChannelResult);
}
/// <summary>
/// Completes the user interface that prompts a user for a certificate.
/// </summary>
/// <param name="iAsyncResult">Represents the status of an asynchrous operation.</param>
public void EndDisplayInitializationUI(IAsyncResult iAsyncResult)
{
// Any given thread can try to use a channel. Most will be on a Multi Threaded Apartment (MTA). To call up a user
// interface, a Single Threaded Apartment (STA) thread must be created.
ClientChannelResult clientChannelResult = iAsyncResult as ClientChannelResult;
// Only one thread at a time is allowed to prompt the user for credentials. The credentials chosen here will be shared
// by all other threads that try to access this type of channel. Clearing the 'IsPrompted' flag will cause the prompt
// to be displayed again allowing the user to change their identity.
lock (syncObject)
{
// If the user cancels out of the login screen, there's no sense in trying to initialize any of the other channels
// with what we know are bad credentials. The channel initializer will patiently sit here until a manual event
// tells it to try prompting the user again.
ChannelStatus.LoginEvent.WaitOne();
// Only prompt the user once for their credentials. After a set of credentials is chosen, those credentials will
// be used by all other threads that use a Basic authentication.
if (ChannelStatus.IsPrompted)
{
// Any worker thread can request a channel, so the user prompt needs to be invoked on a Single Threaded
// Apartment (STA) thread. This structure is used to pass data to and from the thread where the dialog box is
// invoked.
PromptData promptData = new PromptData();
promptData.NetworkCredentials = new NetworkCredential();
promptData.NetworkCredentials.UserName = Properties.Settings.Default.UserName;
promptData.NetworkCredentials.Password = ChannelStatus.Secret as String;
promptData.EndpointAddress = clientChannelResult.IClientChannel.RemoteAddress;
// When running as a Windows application, the dialog box that prompts the user for credentials is run modally,
// preventing the user from accessing the main application until the credential dialog box is dismissed. A
// console application doesn't have the same luxury and must spawn a dedicated thread to handle the user
// interface.
if (Application.Current == null || Application.Current.Dispatcher == null)
{
// When running in a console environment, this will prompt the user from a dedicated thread.
Thread thread = new Thread(PromptBasic);
thread.SetApartmentState(ApartmentState.STA);
thread.Name = "Basic Prompt Thread";
thread.Start(promptData);
thread.Join();
}
else
{
// This will create the dialog box on the main application's message loop.
Application.Current.Dispatcher.Invoke(DispatcherPriority.Normal, new PromptDelegate(PromptBasic),
promptData);
}
// The user has the option to cancel the login operation. If they cancel, the current operation will be
// aborted and further attempts to initialize a channel will be suspended. If not, an attempt is made to use
// the credentials to authorize communication with the web service.
if (promptData.IsCanceled == true)
{
// If no credentials are given, this channel and all others like it are suspended until an external thread
// resets the event.
clientChannelResult.IClientChannel.Abort();
ChannelStatus.LoginEvent.Reset();
return;
}
else
{
// Copy the information out of the dialog box after it has been dismissed. This information is shared
// between all channels using Basic authentication.
UserNameChannelInitializer.networkCredentials = promptData.NetworkCredentials;
// The information from the dialog box is copied to a persistent store when the user selects the 'Save
// Credentials' check box.
Properties.Settings.Default.UserName = UserNameChannelInitializer.networkCredentials.UserName;
// This will prevent the user from being promtped again.
ChannelStatus.IsPrompted = false;
}
}
// the password was reset internally, modify the network credentials accordingly.
else if (ChannelStatus.Secret != null)
{
UserNameChannelInitializer.networkCredentials.Password = ChannelStatus.Secret as String;
ChannelStatus.Secret = null;
}
// This set of network credentials is now available to this channel for authentication.
this.promptedClientCredentials.Credential = UserNameChannelInitializer.networkCredentials;
}
}
