Provides access to members that control the MapControl.
The IMapControl2 interface is a starting point for any tasks related to the MapControl, such as setting general appearance, setting map and display properties, adding and managing data layers and map documents, and drawing and tracking shapes.
Provides access to members that control the MapControl.
The IMapControl3 interface provides additional members for tasks related to the MapControl, such as setting a custom property and suppressing data redraw whilst the MapControl is being resized.
IMapControl3 和IMapControl2 的区别
原文：http://www.cnblogs.com/tianpinganer/p/4982443.html