Is it possibile to create a custom control in outlook which can be placed in the middle of an application? I mean sommething like this:
I know it could be done with the WebViewPane with Add-in Express but can it be achived without buying this product?
Maybe someone has seen some articles about writing sommething like that?
As far as I know this feature is not supported by Outlook API. Products as Add-In Express, btw, can do it by using unofficial and unsupported hooks.
There is a project here that you can look at in order to do the same by yourself. It is an open source project from Microsoft that provides you some kind of API on top of these unsupported hooks.
You can do this without Add-in Express as well, as you can see we did it. As the starting point, you can use the WebViewURL and WebViewOn properties of the Outlook.Folder object to show an empty HTML page instead of the native Outlook list of items (supergrid). Then, using the Outlook Object Model's events (BeforeFolderSwitch and FolderSwitch) you can detect that your folder is selected, create your own control, may be a complex one – UserControl, resize it to fit into the needed area and place it as a child window for the Outlook Explorer window. In general, we used a very similar approach in Add-in Express frameworks. All "unsupported hooks", which are in fact plain WinAPI hooks, will be needed only to track the changes in the Outlook Explorer window size and to align your control or form accordingly.
来源：https://stackoverflow.com/questions/9172764/outlook-2010-add-in-build-custom-webviewpane-without-add-in-express