Comparing an ActiveX Control to a Design-Time Control

Design-time controls are standard ActiveX controls that implement a special interface for generating text. The editor uses the DTC for its run-time text. Once the DTC is used in a file, the editor saves the generated text in the file. This text is processed at run time by downstream text consumers such as browsers and Web server components. Unlike a typical ActiveX control, the DTC is not active at run-time and does not have a binary run-time component.

Design-time controls are like ActiveX controls in that they extend the graphical editing environment of an HTML editor. DTCs are supported by a wide number of HTML editors, including those in Microsoft FrontPage and Visual InterDev.

The underlying technology is a COM-based component solution that allows any host container to use DTCs for easy authoring of HTML or Active Server Pages by providing the following capabilities:

Handle their own user interface drawing
Note When creating a DTC, use property pages instead of inline user interface for setting a DTC's properties. An inline user interface is the graphical representation of the DTC within the hosting document such as a form or other object with controls that accept user input. Although Visual InterDev 6.0 supports inline user interface, this is not a guarantee that all DTC hosts are required to support it now or in the future.
Accept mouse and keyboard input
Provide context menus and property pages

Design-time controls take advantage of the rich OLE design-time mechanisms for capturing user input, such as:

In-place editing
Property pages
Persistence

If you want your DTC to be able to share information with other DTCs in a document, your DTC uses an additional site. Unlike the ActiveX control site which is typically available during the ActiveX control initialization phase of the DTC, the DTC control site is provided independently from the ActiveX control site and is set during a rebind when the DTC is first encountered. Therefore, the DesignTimeControlSite object is managed separately from the ActiveX control site and the Choices engine is implemented separately from the ActiveX control container that provides the ActiveX control site.