As I said earlier, we didn’t test our solution to using the ModalPopupExtender in SharePoint in all situations. Today we made a start to do so. To indicate our successrate: we now use window.showModalDialog with some extra pages…
Lets go through some of the problems we encountered.
- Placing an UpdatePanel around the entire UserControl (with default settings) makes that the entire UserControl is posted back, even when it is a control inside a nested UpdatePanel that posts back. The ASP.NET controls have no problem with this, but the SharePoint InputFormTextBox set to RichText does. The toolbars are not rendered, and the entire HTML is shown. Setting ChildrenAsTriggers would disable this behaviour (it does with default ASP.NET controls), because in that case only the nested UpdatePanel is posted back. Unfortunately we didn’t get to test that.
- The SharePoint page layout doesn’t render properly when using the XHTML Transitional doctype. Probably nothing a redesign of the masterpage (and maybe some controls) can’t handle, but it seems you need time and budget for that. ;)
- The background wasn’t always completely grayed out using the BackgroundCssClass. Sometimes a ribbon of say 10 pixels was shown normal, sometimes the entire background was displayed normal. And clickable! That’s not what we would like to use a modal popup for.