Using C1Popup is very simple. You can declare the popup in XAML on your page like this:
Or you can create one at run-time with any UserControl as its content like this:
C1Popup popup = new C1Popup();
MyUserControl control = new MyUserControl();
popup.Content = control;
// open popup
popup.IsOpen = true;
To open and close C1Popup programmatically you set the IsOpen property. When the control opens it sets focus to itself, so the virtual keyboard (SIP) will close automatically. C1Popup is a very useful control for nearly any kind of Silverlight app on the Phone.
RichTextBox Formatting Sample
We used C1Popup to complete the formatting demo for C1RichTextBox. Just like the format button in Microsoft Word for Windows Phone, we used C1Popup to display many format features supported in C1RichTextBox.
This sample also shows a popup for inserting/editing a hyperlink, as well as undo functionality (not using any popup).