ComGIS出接口扩展功能设计与应用

The Research of Extending Components GIS——The Design to Extend Component Using Outgoing Interface

GIS技术发展掀起了组件化的热潮。但是开发人员当面临 GIS组件实现不了的功能时 ,往往出现难题。这时就可以通过 GIS组件中定义的出接口扩展它的功能 ,完成一些组件 GIS本身不具有的功能。本文探讨了出接口扩展 Com GIS的设计原则 ,并以实例揭示了这一方法如何运用以及它的运行机制 ,并且说明了如何在开发组件式GIS时添加出接口这一功能 ,最后揭示这一机制的发展方向。

With rapid development of GIS in recent years, the trend of components GIS has become more and more popular But because of the encapsulation essence of the object oriented model, programmers can only use the interfaces to communicate with the object without knowing anything about the realization details They will get into dilemma when they encounter those functions that GIS components can not realize In this circumstance, the outgoing interface defined by the GIS components can be used to extend the GIS components to realize those functions This article will introduce how to use the outgoing interface to customize the symbols in MapObjects and illustrate the mechanism of the process Meanwhile, the article will also introduce how to add an outgoing interface when developing GIS components Finally, the article discusses the possible trend of this mechanism