private void OnNavigating(IContent content, NavigatingCancelEventArgs e)
{
// first invoke child frame navigation events
foreach (var f in GetChildFrames()) {
f.OnNavigating(f.Content as IContent, e);
}
e.IsParentFrameNavigating = e.Frame != this;
// invoke IContent.OnNavigating (only if content implements IContent)
if (content != null) {
content.OnNavigatingFrom(e);
}
// raise the Navigating event
if (Navigating != null) {
Navigating(this, e);
}
}
private bool CanNavigate(Uri oldValue, Uri newValue, NavigationType navigationType)
{
var cancelArgs = new NavigatingCancelEventArgs {
Frame = this,
Source = newValue,
IsParentFrameNavigating = true,
NavigationType = navigationType,
Cancel = false,
};
OnNavigating(this.Content as IContent, cancelArgs);
// check if navigation cancelled
if (cancelArgs.Cancel) {
Debug.WriteLine("Cancelled navigation from '{0}' to '{1}'", oldValue, newValue);
if (this.Source != oldValue) {
// enqueue the operation to reset the source back to the old value
Dispatcher.BeginInvoke((Action)(() => {
this.isResetSource = true;
SetCurrentValue(SourceProperty, oldValue);
this.isResetSource = false;
}));
}
return false;
}
return true;
}