/// <summary>
/// Constructor - registers with the message mediator and hooks up any imports/exports
/// with the default MEF catalog
/// </summary>
public ViewModel()
{
// Register with the message mediator - this will locate and bind all message
// targets on this instance. Shouldn't really need to check for existence - it should
// always be present, but just in case someone Unregisters it..
var mediator = Resolve <IMessageMediator>();
if (mediator != null)
{
mediator.Register(this);
}
// Hook up any MEF imports/exports
IDynamicResolver loader = Resolve <IDynamicResolver>();
if (loader != null)
{
try
{
loader.Compose(this);
}
catch (CompositionException)
{
// Can throw if in invalid state - i.e. creating VM on behalf of a view.
}
}
}
/// <summary>
/// This creates the WPF window from a key.
/// </summary>
/// <param name="key">Key</param>
/// <param name="dataContext">DataContext (state) object</param>
/// <param name="setOwner">True/False to set ownership to MainWindow</param>
/// <param name="completedProc">Callback</param>
/// <param name="isModal">True if this is a ShowDialog request</param>
/// <returns>Success code</returns>
private Window CreateWindow(string key, object dataContext, bool setOwner, EventHandler <UICompletedEventArgs> completedProc, bool isModal)
{
if (string.IsNullOrEmpty(key))
{
throw new ArgumentNullException("key");
}
// If we've not scanned for available exported views, do so now.
if (!_haveLoadedVisuals)
{
CheckForDynamicRegisters();
}
Type winType;
lock (_registeredWindows)
{
if (!_registeredWindows.TryGetValue(key, out winType))
{
return(null);
}
}
// Create the top level window
var win = (Window)Activator.CreateInstance(winType);
if (setOwner)
{
win.Owner = Application.Current.MainWindow;
}
// Register the view with MEF to resolve any imports.
try
{
_dynamicLoader.Compose(win);
}
catch (CompositionException)
{
}
if (dataContext != null)
{
win.DataContext = dataContext;
var bvm = dataContext as ViewModel;
// Wire up the event handlers. Go through the dispatcher in case the window
// is being created on a secondary thread so the primary thread can invoke the
// event handlers.
if (bvm != null)
{
if (isModal)
{
bvm.CloseRequest += ((s, e) => win.Dispatcher.Invoke((Action)(() =>
{
try
{
win.DialogResult = e.Result;
}
catch (InvalidOperationException)
{
win.Close();
}
}), null));
}
else
{
bvm.CloseRequest += ((s, e) => win.Dispatcher.Invoke((Action)(win.Close), null));
}
bvm.ActivateRequest += ((s, e) => win.Dispatcher.Invoke((Action)(() => win.Activate()), null));
}
}
if (completedProc != null)
{
win.Closed +=
(s, e) =>
completedProc(this,
new UICompletedEventArgs {
State = dataContext, Result = (isModal) ? win.DialogResult : null
});
}
return(win);
}
/// <summary>
/// Construct the service provider. Resolve all the imported services.
/// </summary>
public ServiceProvider()
{
_mefLoader.Compose(this);
}
