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<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">所有的</span><span lang="EN-US">.NET</span><span style="FONT-FAMILY: 宋体">语言都必须支持</span><span lang="EN-US">CLS</span><span style="FONT-FAMILY: 宋体">。在讨论</span><span lang="EN-US">.NET</span><span style="FONT-FAMILY: 宋体">语言时，必须区分</span><span lang="EN-US">.NET consumer </span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US"> .NET extender</span><span style="FONT-FAMILY: 宋体">工具。</span></p>
<p class="MsoNormal"><span lang="EN-US">.NET consumer</span><span style="FONT-FAMILY: 宋体">工具只使用</span><span lang="EN-US">.NET Framework</span><span style="FONT-FAMILY: 宋体">中的类，它不能创建可以用于其他语言的</span><span lang="EN-US">.NET</span><span style="FONT-FAMILY: 宋体">类。</span><span lang="EN-US">.NET consumer </span><span style="FONT-FAMILY: 宋体">工具可以使用任何与</span><span lang="EN-US">CLS</span><span style="FONT-FAMILY: 宋体">兼容的类。</span><span lang="EN-US">.NET extender</span><span style="FONT-FAMILY: 宋体">工具则可以满足客户的要求，另外还可以继承任何与</span><span lang="EN-US">CLS</span><span style="FONT-FAMILY: 宋体">兼容的</span><span lang="EN-US">.NET</span><span style="FONT-FAMILY: 宋体">类，并定义了可以由客户使用的新</span><span lang="EN-US">CLS</span><span style="FONT-FAMILY: 宋体">兼容类。</span><span lang="EN-US">C++</span><span style="FONT-FAMILY: 宋体">、</span><span lang="EN-US">VB.NET</span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US"> C# </span><span style="FONT-FAMILY: 宋体">都是</span><span lang="EN-US">.NET extender</span><span style="FONT-FAMILY: 宋体">工具，使用这些语言可以创建</span><span lang="EN-US">CLS</span><span style="FONT-FAMILY: 宋体">兼容类。</span></p>
<h4><span lang="ES">1. CLSCompliant</span><span style="FONT-FAMILY: 黑体">属性</span></h4>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">利用</span><span lang="ES">CLSCompliant</span><span style="FONT-FAMILY: 宋体">属性</span><span style="FONT-FAMILY: 宋体">，</span><span style="FONT-FAMILY: 宋体">可以把程序集标记为与</span><span lang="ES">CLS</span><span style="FONT-FAMILY: 宋体">兼容</span><span style="FONT-FAMILY: 宋体">，</span><span style="FONT-FAMILY: 宋体">这样可以确保这个程序集中的类能用于所有的</span><span lang="ES">.NET consumer</span><span style="FONT-FAMILY: 宋体">工具。在公共方法或受保护的方法中使用与</span><span lang="EN-US">CLS</span><span style="FONT-FAMILY: 宋体">不兼容的数据类型时，编译器会给出警告。在私有方法中使用什么样的数据类型则不重要，因为在类的外部使用其他语言时，根本就不能访问私有方法。</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">当在公共方法和受保护的方法中使用与</span><span lang="EN-US">CLS</span><span style="FONT-FAMILY: 宋体">不兼容的类型时，为了让编译器发出警告，可以设置程序集中的属性</span><span lang="EN-US">CLSCompliant</span><span style="FONT-FAMILY: 宋体">。把这个属性添加到文件</span><span lang="EN-US">AssemblyInfo.cs</span><span style="FONT-FAMILY: 宋体">中：</span></p>
<p class="2" style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 8.15pt"><span lang="ES">[assembly: System.CLSCompliant(true)]</span><span class="MsoCommentReference"><span lang="ES" style="DISPLAY: none; FONT-SIZE: 8pt; FONT-FAMILY: 'Baskerville BE Regular'"> </span></span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">这样，在程序集中定义的所有类型和公共方法就都是兼容的。当参数的数据类型是不兼容的</span><span lang="EN-US">uint</span><span style="FONT-FAMILY: 宋体">时，编译器就会发出如下错误：</span></p>
<p class="a6" style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 8.15pt"><strong><span lang="EN-US">error CS3001: Argument type uint is not CLS-compliant </span></strong></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">把程序集标记为兼容时，仍可以定义不兼容的方法。如果要重写某些方法，使其参数是兼容和不兼容的数据类型，就必须把类中不兼容的方法的</span><span lang="EN-US">CLSCompliant </span><span style="FONT-FAMILY: 宋体">属性设置为</span><span lang="EN-US">false</span><span style="FONT-FAMILY: 宋体">。</span><span lang="EN-US">CLSCompliant </span><span style="FONT-FAMILY: 宋体">属性可以应用到类型、方法、属性、字段和事件上：</span></p>
<p class="2" style="MARGIN-TOP: 8.15pt"><span lang="ES">[CLSCompliant(false)]</span></p>
<p class="a6"><span lang="ES">void Method(uint i) </span></p>
<p class="a6"><span lang="ES">{</span></p>
<p class="a6"><span lang="ES">&nbsp;&nbsp; //...</span></p>
<h4><span lang="ES">2. CLS</span><span style="FONT-FAMILY: 黑体">规则</span></h4>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">那么程序集与</span><span lang="ES">CLS</span><span style="FONT-FAMILY: 宋体">兼容有什么要求呢？</span></p>
<p class="1" style="MARGIN-LEFT: 37.55pt; FTEL: -16.1pt"><span lang="ES">●<span style="FONT: 7pt 'Times New Roman'">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体">方法原型中的所有类型都必须与</span><span lang="ES">CLS</span><span style="FONT-FAMILY: 宋体">兼容。</span></p>
<p class="1" style="MARGIN-LEFT: 37.55pt; FTEL: -16.1pt"><span lang="ES">●<span style="FONT: 7pt 'Times New Roman'">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体">数组元素的元素类型必须与</span><span lang="ES">CLS</span><span style="FONT-FAMILY: 宋体">兼容。数组中第一个元素的下标必须是</span><span lang="ES">0</span><span style="FONT-FAMILY: 宋体">。</span></p>
<p class="1" style="MARGIN-LEFT: 37.55pt; FTEL: -16.1pt"><span lang="ES">●<span style="FONT: 7pt 'Times New Roman'">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span lang="ES">CLS</span><span style="FONT-FAMILY: 宋体">兼容类必须继承于</span><span lang="ES">CLS</span><span style="FONT-FAMILY: 宋体">兼容类，当然，</span><span lang="ES">System.Object</span><span style="FONT-FAMILY: 宋体">是与</span><span lang="ES">CLS</span><span style="FONT-FAMILY: 宋体">兼容的。</span></p>
<p class="1" style="MARGIN-LEFT: 37.55pt; FTEL: -16.1pt"><span lang="ES">●<span style="FONT: 7pt 'Times New Roman'">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体">在</span><span lang="ES">CLS</span><span style="FONT-FAMILY: 宋体">兼容类中，方法名是不区分大小写的，两个方法不能仅根据其名称中字母的大小写来区分。</span></p>
<p class="1" style="MARGIN-LEFT: 37.55pt; FTEL: -16.1pt"><span lang="ES">●<span style="FONT: 7pt 'Times New Roman'">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span style="FONT-FAMILY: 宋体">枚举的类型必须是</span><span lang="ES">Int16</span><span style="FONT-FAMILY: 宋体">、</span><span lang="ES">Int32</span><span style="FONT-FAMILY: 宋体">或</span><span lang="ES">Int64</span><span style="FONT-FAMILY: 宋体">。其他类型的枚举都是不兼容的。</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">上述列举的要求只适用于公共成员和受保护的成员。私有方法则无需考虑这些要求，它们可以使用不兼容的类型，而程序集仍然是兼容的。</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">除了这些要求外，还应遵循更一般的命名约定</span><span lang="EN-US">(</span><span style="FONT-FAMILY: 宋体">详见第</span><span lang="EN-US">2</span><span style="FONT-FAMILY: 宋体">章</span><span lang="EN-US">)</span><span style="FONT-FAMILY: 宋体">。</span><span lang="EN-US">CLS</span><span style="FONT-FAMILY: 宋体">兼容类不需要严格遵循这些规则，但遵循这些规则会使工作更容易完成。</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">除了遵循这些命名约定，以支持多种语言外，还必须注意包含类型名称的方法名称。数据类型名是语言所特定的。</span><span lang="EN-US">C#</span><span style="FONT-FAMILY: 宋体">中的</span><span lang="EN-US">int</span><span style="FONT-FAMILY: 宋体">、</span><span lang="EN-US">long</span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US">float </span><span style="FONT-FAMILY: 宋体">类型等同于</span><span lang="EN-US">VB.NET </span><span style="FONT-FAMILY: 宋体">中的</span><span lang="EN-US">Integer</span><span style="FONT-FAMILY: 宋体">、</span><span lang="EN-US">Long</span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US"> Single</span><span style="FONT-FAMILY: 宋体">。在方法名中使用数据类型名时，应使用一般的类型名，而不是某语言特定的类型名，即应使用</span><span lang="EN-US">Int32</span><span style="FONT-FAMILY: 宋体">、</span><span lang="EN-US">Int64</span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US"> Single</span><span style="FONT-FAMILY: 宋体">：</span></p>
<p class="2" style="MARGIN-TOP: 8.15pt"><span lang="EN-US">int ReadInt32();</span></p>
<p class="2"><span lang="EN-US">long ReadInt64();</span></p>
<p class="2" style="FTEL: 8.15pt"><span lang="EN-US">float ReadSingle();</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">可以看出，在利用</span><span lang="EN-US">CLS</span><span style="FONT-FAMILY: 宋体">规范和规则进行编译时，很容易创建出可以用于多种语言的组件。不需要使用所有的</span><span lang="EN-US">.NET consumer</span><span style="FONT-FAMILY: 宋体">语言来测试该组件。</span></p></div>
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                        <div style='float:left;width:49%'>·<a href='100165403.htm'>13.3.1  CTS和CLS</a></div><div style='float:right;width:49%'>·<a href='100165404.htm'>13.3.2  语言无关性(1)</a></div><div style='float:left;width:49%'>·<a href='100165405.htm'>13.3.2  语言无关性(2)</a></div><div style='float:right;width:49%'>·<a href='100165407.htm'>13.4  全局程序集缓存</a></div><div style='float:left;width:49%'>·<a href='100165408.htm'>13.4.1  本机图像生成器</a></div><div style='float:right;width:49%'>·<a href='100165409.htm'>13.4.2  全局程序集缓存查看器</a></div></div>
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