《com 原理与应用》学习笔记 - linuszhu的专栏 - csdnblog.htm

OPC document,collecting~

style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">特性</SPAN></P>
<P class=MsoNormal><SPAN lang=EN><SPAN style="mso-spacerun: yes">&nbsp;&nbsp; 
</SPAN></SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">可重用性：包容和聚合</SPAN></P>
<P class=MsoNormal><SPAN lang=EN><SPAN style="mso-spacerun: yes">&nbsp;&nbsp; 
</SPAN></SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">进程透明性</SPAN><SPAN 
lang=EN> (</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">待学</SPAN><SPAN 
lang=EN>)</SPAN></P>
<P class=MsoNormal><SPAN lang=EN><SPAN style="mso-spacerun: yes">&nbsp;&nbsp; 
</SPAN></SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">安全性</SPAN><SPAN 
lang=EN> (</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">待学</SPAN><SPAN 
lang=EN>)</SPAN></P>
<P class=MsoNormal><SPAN lang=EN><SPAN style="mso-spacerun: yes">&nbsp;&nbsp; 
</SPAN></SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">多线程特性</SPAN><SPAN 
lang=EN> (</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">待学</SPAN><SPAN 
lang=EN>)</SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">⊙</SPAN> 
<SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">第五章</SPAN> 
<SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">用</SPAN><SPAN 
lang=EN> Visual C++ </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">开发</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">应用</SPAN></P>
<P class=MsoNormal><SPAN lang=EN><SPAN style="mso-spacerun: yes">&nbsp;&nbsp; 
</SPAN>Win32 SDK </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">提供的一些头文件的说明</SPAN></P>
<P class=MsoNormal><SPAN lang=EN><SPAN style="mso-spacerun: yes">&nbsp;&nbsp; 
</SPAN></SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">与</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">接口有关的一些宏</SPAN></P>
<P class=MsoNormal><SPAN 
lang=EN>===============================================================================</SPAN></P>
<P class=MsoNormal><SPAN lang=EN>&nbsp;<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN lang=EN>&nbsp;<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">正</SPAN> 
<SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">文</SPAN></P>
<P class=MsoNormal><SPAN 
lang=EN>===============================================================================</SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">⊙</SPAN> 
<SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">第一章</SPAN> 
<SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">概述</SPAN></P>
<P class=MsoNormal><SPAN 
lang=EN>===============================================================================</SPAN></P>
<P class=MsoNormal><SPAN lang=EN><SPAN style="mso-spacerun: yes">&nbsp;&nbsp; 
</SPAN>COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">是什么</SPAN></P>
<P class=MsoNormal><SPAN 
lang=EN>-------------------------------------------------------------------------------</SPAN></P>
<P class=MsoNormal><SPAN lang=EN>COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">是由</SPAN><SPAN 
lang=EN> Microsoft </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">提出的组件标准，它不仅定义了组件程序之间进行交互的标准，并且也提供了组件程序运行所需的环境。在</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">标准中，一个组件程序也被称为一个模块，它可以是一个动态链接库，被称为进程内组件</SPAN><SPAN 
lang=EN>(in-process component)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">；也可以是一个可执行程序</SPAN><SPAN 
lang=EN>(</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">即</SPAN><SPAN 
lang=EN> EXE </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">程序</SPAN><SPAN 
lang=EN>)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，被称作进程外组件</SPAN><SPAN 
lang=EN>(out-of-process component)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。一个组件程序可以包含一个或多个组件对象，因为</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">是以对象为基本单元的模型，所以在程序与程序之间进行通信时，通信的双方应该是组件对象，也叫做</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象，而组件程序</SPAN><SPAN 
lang=EN>(</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">或称作</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">程序</SPAN><SPAN 
lang=EN>)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">是提供</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象的代码载体。</SPAN></P>
<P class=MsoNormal><SPAN lang=EN>&nbsp;<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN lang=EN>COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象不同于一般面向对象语言</SPAN><SPAN 
lang=EN>(</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">如</SPAN><SPAN 
lang=EN> C++ </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">语言</SPAN><SPAN 
lang=EN>)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中的对象概念，</SPAN><SPAN 
lang=EN>COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象是建立在二进制可执行代码级的基础上，而</SPAN><SPAN 
lang=EN> C++ </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">等语言中的对象是建立在源代码级基础上的，因此</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象是语言无关的。这一特性使用不同编程语言开发的组件对象进行交互成为可能。</SPAN></P>
<P class=MsoNormal><SPAN lang=EN>&nbsp;<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN 
lang=EN>-------------------------------------------------------------------------------</SPAN></P>
<P class=MsoNormal><SPAN lang=EN><SPAN style="mso-spacerun: yes">&nbsp;&nbsp; 
</SPAN>COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象与接口</SPAN></P>
<P class=MsoNormal><SPAN 
lang=EN>-------------------------------------------------------------------------------</SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">类似于</SPAN><SPAN 
lang=EN> C++ </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中对象的概念，对象是某个类</SPAN><SPAN 
lang=EN>(class)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的一个实例；而类则是一组相关的数据和功能组合在一起的一个定义。使用对象的应用</SPAN><SPAN 
lang=EN>(</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">或另一个对象</SPAN><SPAN 
lang=EN>)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">称为客户，有时也称为对象的用户。</SPAN></P>
<P class=MsoNormal><SPAN lang=EN>&nbsp;<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">接口是一组逻辑上相关的函数集合，其函数也被称为接口成员函数。按照习惯，接口名常是以“</SPAN><SPAN 
lang=EN>I</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">”为前缀。对象通过接口成员函数为客户提供各种形式的服务。</SPAN></P>
<P class=MsoNormal><SPAN lang=EN>&nbsp;<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">模型中，对象本身对于客户来说是不可见的，客户请求服务时，只能通过接口进行。每一个接口都由一个</SPAN><SPAN 
lang=EN> 128 </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">位的全局唯一标识符</SPAN><SPAN 
lang=EN>(GUID</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，</SPAN><SPAN 
lang=EN>Global Unique Identifier)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">来标识。客户通过</SPAN><SPAN 
lang=EN> GUID </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">来获得接口的指针，再通过接口指针，客户就可以调用其相应的成员函数。</SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">与接口类似，每个组件也用一个</SPAN><SPAN 
lang=EN> 128 </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">位</SPAN><SPAN 
lang=EN> GUID </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">来标识，称为</SPAN><SPAN 
lang=EN> CLSID(class identifer</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，类标识符或类</SPAN><SPAN 
lang=EN> ID)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，用</SPAN><SPAN 
lang=EN> CLSID </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">标识对象可以保证</SPAN><SPAN 
lang=EN>(</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">概率意义上</SPAN><SPAN 
lang=EN>)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在全球范围内的唯一性。实际上，客户成功地创建对象后，它得到的是一个指向对象某个接口的指针，因为</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象至少实现一个接口</SPAN><SPAN 
lang=EN>(</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">没有接口的</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象是没有意义的</SPAN><SPAN 
lang=EN>)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">，所以客户就可以调用该接口提供的所有服务。根据</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">规范，一个</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象如果实现了多个接口，则可以从某个接口得到该对象的任意其他接口。从这个过程我们也可以看出，客户与</SPAN> 
<SPAN lang=EN>COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象只通过接口打交道，对象对于客户来说只是一组接口。</SPAN></P>
<P class=MsoNormal><SPAN lang=EN>&nbsp;<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN 
lang=EN>-------------------------------------------------------------------------------</SPAN></P>
<P class=MsoNormal><SPAN lang=EN><SPAN style="mso-spacerun: yes">&nbsp;&nbsp; 
</SPAN>COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">进程模型</SPAN></P>
<P class=MsoNormal><SPAN 
lang=EN>-------------------------------------------------------------------------------</SPAN></P>
<P class=MsoNormal><SPAN lang=EN>COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">所提供的服务组件对象在实现时有两种进程模型：进程内对象和进程外对象。如果是进程内对象，则它在客户进程空间中运行；如果是进程外对象，则它运行在同机器上的另一个进程空间或者在远程机器的空间。</SPAN></P>
<P class=MsoNormal><SPAN lang=EN>&nbsp;<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">进程内服务程序：</SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">服务程序被加载到客户的进程空间，在</SPAN><SPAN 
lang=EN> Windows </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">环境下，通常服务程序的代码以动态连接库</SPAN><SPAN 
lang=EN>(DLL)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的形式实现。</SPAN></P>
<P class=MsoNormal><SPAN lang=EN>&nbsp;<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">本地服务程序：</SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">服务程序与客户程序运行在同一台机器上，服务程序是一个独立的应用程序，通常它是一个</SPAN><SPAN 
lang=EN> EXE </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">文件。</SPAN></P>
<P class=MsoNormal><SPAN lang=EN>&nbsp;<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">远程服务程序：</SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">服务程序运行在与客户不同的机器上，它既可以是一个</SPAN><SPAN 
lang=EN> DLL </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">模块，也可以是一个</SPAN><SPAN 
lang=EN> EXE </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">文件。如果远程服务程序是以</SPAN><SPAN 
lang=EN> DLL </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">形式实现的话，则远程机器会创建一个代理进程。</SPAN></P>
<P class=MsoNormal><SPAN lang=EN>&nbsp;<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">虽然</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象有不同的进程模型，但这种区别对于客户程序来说是透明的，因此客户程序在使用组件对象时可以不管这种区别的存在，只要遵照</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">规范即可。然而，在实现</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象时，还是应该慎重选择进程模型。进程内模型的优点是效率高，但组件不稳定会引起客户进程崩溃，因此组件可能会危及客户；</SPAN><SPAN 
lang=EN>(savetime </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">注：这里有点问题，如果组件不稳定，进程外模型也同样会出问题，可能是因为进程内组件和客户同处一个地址空间，出现冲突的可能性比较大？</SPAN><SPAN 
lang=EN>)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">进程外模型的优点是稳定性好，组件进程不会危及客户程序，一个组件进程可以为多个客户进程提供服务，但进程外组件开销大，而且调用效率相对低一点。</SPAN></P>
<P class=MsoNormal><SPAN lang=EN>&nbsp;<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN 
lang=EN>-------------------------------------------------------------------------------</SPAN></P>
<P class=MsoNormal><SPAN lang=EN><SPAN style="mso-spacerun: yes">&nbsp;&nbsp; 
</SPAN>COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">可重用性</SPAN></P>
<P class=MsoNormal><SPAN 
lang=EN>-------------------------------------------------------------------------------</SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">由于</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">标准是建立在二进制代码级的，因此</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象的可重用性与一般的面向对象语言如</SPAN><SPAN 
lang=EN> C++ </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">中对象的重用过程不同。对于</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象的客户程序来说，它只是通过接口使用对象提供的服务，它并不知道对象内部的实现过程，因此，组件对象的重用性可建立在组件对象的行为方式上，而不是具体实现上，这是建立重用的关键。</SPAN><SPAN 
lang=EN>COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">用两种机制实现对象的重用。我们假定有两个</SPAN><SPAN 
lang=EN> COM </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象，对象</SPAN><SPAN 
lang=EN>1 </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">希望能重用对象</SPAN><SPAN 
lang=EN>2 </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的功能，我们把对象</SPAN><SPAN 
lang=EN>1 </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">称为外部对象，对象</SPAN><SPAN 
lang=EN>2 </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">称为内部对象。</SPAN></P>
<P class=MsoNormal><SPAN lang=EN>&nbsp;<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN lang=EN>(1)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">包容方式。</SPAN></P>
<P class=MsoNormal><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象</SPAN><SPAN 
lang=EN>1 </SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-ascii-font-fami