Using Callbacks to Retrieve Information from MapInfo®

You can tune your Integrated Mapping application to force MapInfo® automatically send information to your client program. For example, you can set up your program so that whenever a Map window changes, MapInfo® will call your client program and send it window ID (Integer) that was changed. This type of notification, where an event causes MapInfo® to call your client program, is known as Callbacks. Callbacks allow MapInfo® to send information to your client program under the following circumstances:

• The user interacts with a MapInfo® window while using a custom tool.

For example, if the user clicks and drags on a Map window to draw a line, MapInfo can call your client program to communicate the x- and y-coordinates chosen by the user.

• The user chooses a menu command.

For example, suppose your application customizes MapInfo's shortcut menus (the menus that appear if the user right-clicks). When the user chooses a custom command from a shortcut menu, MapInfo can call your client program to notify your program of the menu event.

• A Map window was changed.

If the user changes the contents of the Map window (e.g. by adding or removing map layers, or by panning the map), MapInfo® can send your client program the Integer window ID of the window that changed. (This is analogous to MapBasic's special handler procedure, WinChangedHandler).

• The status bar text changes in MapInfo.

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Using MapInfo Callbacks Manager with Borland® Delphi

Information about using MapInfo Callbacks Manager with Borland® Delphi can be found here.

Using MapInfo Callbacks Manager with Microsoft® Visual Basic

Information about using MapInfo Callbacks Manager with Microsoft® Visual Basic can be found here.