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<p class="2" style="MARGIN: 8.15pt 0cm 0pt 21.45pt; TEXT-INDENT: 18.45pt"><span lang="EN-US">class MyClass</span></p>
<p class="2" style="MARGIN: 0cm 0cm 8.15pt 21.45pt; TEXT-INDENT: 18.45pt"><span lang="EN-US">{</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">定义了一个普通的</span><span lang="EN-US">C++</span><span style="FONT-FAMILY: 宋体">类，而代码：</span></p>
<p class="2" style="MARGIN: 8.15pt 0cm 0pt 21.45pt; TEXT-INDENT: 18.45pt"><span lang="EN-US">__gc class MyClass</span></p>
<p class="2" style="MARGIN: 0cm 0cm 8.15pt 21.45pt; TEXT-INDENT: 18.45pt"><span lang="EN-US">{</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">生成了一个托管类，就好像使用</span><span lang="EN-US">C#</span><span style="FONT-FAMILY: 宋体">或</span><span lang="EN-US">VB.NET</span><span style="FONT-FAMILY: 宋体">编写类一样。实际上，托管</span><span lang="EN-US">C++</span><span style="FONT-FAMILY: 宋体">比</span><span lang="EN-US">C#</span><span style="FONT-FAMILY: 宋体">更优越的一点是可以在托管</span><span lang="EN-US">C++</span><span style="FONT-FAMILY: 宋体">代码中调用非托管</span><span lang="EN-US">C++</span><span style="FONT-FAMILY: 宋体">类，而不必采用</span><span lang="EN-US">COM</span><span style="FONT-FAMILY: 宋体">交互功能。</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">如果在托管类型上试图使用</span><span lang="EN-US">.NET</span><span style="FONT-FAMILY: 宋体">不支持的特性</span><span lang="EN-US">(</span><span style="FONT-FAMILY: 宋体">例如，模板或类的多继承</span><span lang="EN-US">)</span><span style="FONT-FAMILY: 宋体">，编译器就会出现一个错误。另外，在使用托管类时，还需要使用非标准的</span><span lang="EN-US">C++</span><span style="FONT-FAMILY: 宋体">特性</span><span lang="EN-US">(</span><span style="FONT-FAMILY: 宋体">例如上述代码中的</span><span class="codeintext-PRODUCTION"><span lang="EN-US" style="FONT-FAMILY: 'Times New Roman'">__gc</span></span><span class="codeintext-PRODUCTION"><span style="FONT-FAMILY: 宋体">关键字</span></span><span class="codeintext-PRODUCTION"><span lang="EN-US" style="FONT-FAMILY: 'Times New Roman'">)</span></span><span style="FONT-FAMILY: 宋体">。</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">因为</span><span lang="EN-US">C++</span><span style="FONT-FAMILY: 宋体">允许低级指针操作，</span><span lang="EN-US">C++</span><span style="FONT-FAMILY: 宋体">编译器不能生成可以通过</span><span lang="EN-US">CLR</span><span style="FONT-FAMILY: 宋体">内存类型安全测试的代码。如果</span><span lang="EN-US">CLR</span><span style="FONT-FAMILY: 宋体">把代码标识为内存类型安全是非常重要的，就需要用其他一些语言编写源代码，例如</span><span lang="EN-US">C# </span><span style="FONT-FAMILY: 宋体">或</span><span lang="EN-US">VB.NET</span><span style="FONT-FAMILY: 宋体">。</span></p>
<p class="MsoNormal"><span lang="EN-US" style="FONT-FAMILY: Arial">Visual </span><span lang="EN-US" style="FONT-FAMILY: Arial">J#</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">。在</span><span lang="EN-US">.NET Framework 1.1</span><span style="FONT-FAMILY: 宋体">版本推出之前，用户必须下载相应的软件，才能使用</span><span lang="EN-US">J#</span><span style="FONT-FAMILY: 宋体">。现在</span><span lang="EN-US">J#</span><span style="FONT-FAMILY: 宋体">语言内置于</span><span lang="EN-US">.NET Framework</span><span style="FONT-FAMILY: 宋体">中。因此，</span><span lang="EN-US">J#</span><span style="FONT-FAMILY: 宋体">用户可以利用</span><span lang="EN-US" style="LETTER-SPACING: -0.1pt">Visual Studio .NET</span><span style="FONT-FAMILY: 宋体; LETTER-SPACING: -0.1pt">的所有常见特性。</span><span lang="EN-US">Microsoft</span><span style="FONT-FAMILY: 宋体">希望大多数</span><span lang="EN-US">J++</span><span style="FONT-FAMILY: 宋体">用户认为他们在使用</span><span lang="EN-US">.NET</span><span style="FONT-FAMILY: 宋体">时，将很容易使用</span><span lang="EN-US">J#</span><span style="FONT-FAMILY: 宋体">。</span><span lang="EN-US">J#</span><span style="FONT-FAMILY: 宋体">不使用</span><span lang="EN-US">Java</span><span style="FONT-FAMILY: 宋体">运行库，而是使用与其他</span><span lang="EN-US">.NET</span><span style="FONT-FAMILY: 宋体">兼容语言一样的基类库。这说明，与</span><span lang="EN-US">C#</span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US">VB.NET</span><span style="FONT-FAMILY: 宋体">一样，可以使用</span><span lang="EN-US">J#</span><span style="FONT-FAMILY: 宋体">创建</span><span lang="EN-US">ASP.NET Web</span><span style="FONT-FAMILY: 宋体">应用程序、</span><span lang="EN-US">Windows</span><span style="FONT-FAMILY: 宋体">窗体、</span><span lang="EN-US">XML Web</span><span style="FONT-FAMILY: 宋体">服务和其他应用程序。</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 黑体">脚本语言</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">的推出，一般认为它们的重要性在降低。另一方面，</span><span lang="EN-US">JScript</span><span style="FONT-FAMILY: 宋体">升级到</span><span lang="EN-US">JScript.NET</span><span style="FONT-FAMILY: 宋体">。</span><span lang="EN-US">ASP.NET</span><span style="FONT-FAMILY: 宋体">页面可以用</span><span lang="EN-US">JScript.NET</span><span style="FONT-FAMILY: 宋体">编写，现在可以把</span><span lang="EN-US">JScript.NET</span><span style="FONT-FAMILY: 宋体">当作一种编译语言来运行，而不是解释性的语言，也可以编写输入量比较大的</span><span lang="EN-US">JScript.NET</span><span style="FONT-FAMILY: 宋体">代码。有了</span><span lang="EN-US">ASP.NET</span><span style="FONT-FAMILY: 宋体">后，就没有必要在服务器端的</span><span lang="EN-US">Web</span><span style="FONT-FAMILY: 宋体">页面上使用脚本语言了，但</span><span lang="EN-US">VBA</span><span style="FONT-FAMILY: 宋体">仍用作</span><span lang="EN-US">Office</span><span style="FONT-FAMILY: 宋体">文档和</span><span lang="EN-US">Visual Studio</span><span style="FONT-FAMILY: 宋体">宏语言。</span></p>
<p class="MsoNormal"><span lang="EN-US" style="FONT-FAMILY: Arial">COM</span><span style="FONT-FAMILY: 黑体">和</span><span lang="EN-US" style="FONT-FAMILY: Arial">COM+</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">从技术上讲，</span><span lang="EN-US">COM </span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US"> COM+</span><span style="FONT-FAMILY: 宋体">并不是面向</span><span lang="EN-US">.NET</span><span style="FONT-FAMILY: 宋体">的技术，因为基于它们的组件不能编译为</span><span lang="EN-US">IL(</span><span style="FONT-FAMILY: 宋体">但如果原来的</span><span lang="EN-US">COM</span><span style="FONT-FAMILY: 宋体">组件是用</span><span lang="EN-US">C++</span><span style="FONT-FAMILY: 宋体">编写的，使用托管</span><span lang="EN-US">C++</span><span style="FONT-FAMILY: 宋体">，在某种程度上可以这么做</span><span lang="EN-US">)</span><span style="FONT-FAMILY: 宋体">。但是，</span><span lang="EN-US">COM+</span><span style="FONT-FAMILY: 宋体">仍然是一个重要的工具，因为其特性没有在</span><span lang="EN-US">.NET</span><span style="FONT-FAMILY: 宋体">中完全实现。另外，</span><span lang="EN-US">COM</span><span style="FONT-FAMILY: 宋体">组件仍可以使用<span style="LETTER-SPACING: -0.5pt">&mdash;&mdash;</span></span><span lang="EN-US">.NET</span><span style="FONT-FAMILY: 宋体">组合了</span><span lang="EN-US">COM</span><span style="FONT-FAMILY: 宋体">的互操作性，从而使托管代码可以调用</span><span lang="EN-US">COM</span><span style="FONT-FAMILY: 宋体">组件，</span><span lang="EN-US">COM</span><span style="FONT-FAMILY: 宋体">组件也可以调用托管代码</span><span lang="EN-US">(</span><span style="FONT-FAMILY: 宋体">见第</span><span lang="EN-US">29</span><span style="FONT-FAMILY: 宋体">章</span><span lang="EN-US">)</span><span style="FONT-FAMILY: 宋体">。在大多数情况中，把新组件编写为</span><span lang="EN-US">.NET</span><span style="FONT-FAMILY: 宋体">组件，其多数目的是为了比较方便，因为这样可以利用</span><span lang="EN-US">.NET</span><span style="FONT-FAMILY: 宋体">基类和托管代码的其他优点。</span></p></div>
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