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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>Hyperlinked ECMA C# Language Specification</title><meta name="author" content="Jon Jagger" /><link rel="stylesheet" href="ecma334.css"></link></head><body><div align="right"><em><a href="http://www.jaggersoft.com">Jon Jagger</a></em></div><div align="right"><a href="mailto:jon@jaggersoft.com">jon@jaggersoft.com</a></div><form method="get" action="http://search.atomz.com/search/"><input size="30" name="sp-q"></input><input type="submit" value="Search C# Spec"></input><input type="hidden" name="sp-a" value="sp10024177"></input><input type="hidden" name="sp-f" value="ISO-8859-1"></input></form><a href="toc.htm">Table of Contents</a> <a href="1.htm">1</a> <a href="2.htm">2</a> <a href="3.htm">3</a> <a href="4.htm">4</a> <a href="5.htm">5</a> <a href="6.htm">6</a> <a href="7.htm">7</a> <a href="8.htm">8</a> <a href="9.htm">9</a> <a href="10.htm">10</a> <a href="11.htm">11</a> <a href="12.htm">12</a> <a href="13.htm">13</a> <a href="14.htm">14</a> <a href="15.htm">15</a> <a href="16.htm">16</a> <a href="17.htm">17</a> <a href="18.htm">18</a> <a href="19.htm">19</a> <a href="20.htm">20</a> <a href="21.htm">21</a> <a href="22.htm">22</a> <a href="23.htm">23</a> <a href="24.htm">24</a> <a href="25.htm">25</a> <a href="notes.htm">Notes</a> <a href="HyperlinkedCSharpECMA.zip">Download</a><span class="ruler"></span><span class="heading">ECMA-334 C# Language Specification</span><span class="navigate"><a href="17.3.htm"><img src="previous.gif" alt="previous" border="0" /></a><a href="17.4.1.htm"><img src="next.gif" alt="next" border="0" /></a></span><span class="clause-depth"><a href="16.htm"><img src="previous.gif" alt="previous at this level" border="0" /></a><a href="18.htm"><img src="next.gif" alt="next at this level" border="0" /></a> <span class="clause-number-link"><a href="17.htm">17</a></span><span class="clause-title-previous"> Classes</span></span><span class="clause-depth"><a href="17.3.htm"><img src="previous.gif" alt="previous at this level" border="0" /></a><a href="17.5.htm"><img src="next.gif" alt="next at this level" border="0" /></a> <span class="clause-number">17.4</span><span class="clause-title"> Fields</span></span><span class="locator">
Paragraph 1</span><span class="paragraph"><span class="sentence"><span class="sentence-number">1</span> <a name="P1S1"></a>A field is a member that represents a variable associated with an object or class.</span> <span class="sentence"><span class="sentence-number">2</span> <a name="P1S2"></a>A <span class="non-terminal"><a href="17.4.htm#field-declaration">field-declaration</a></span> introduces one or more fields of a given type.</span> <span class="grammar-production"><span class="name"><a name="field-declaration"></a>field-declaration</span> : <span class="rhs"><span class="non-terminal"><a href="24.2.htm#attributes">attributes</a></span><sub>opt</sub> <span class="non-terminal"><a href="17.4.htm#field-modifiers">field-modifiers</a></span><sub>opt</sub> <span class="non-terminal"><a href="11.htm#type">type</a></span> <span class="non-terminal"><a href="17.4.htm#variable-declarators">variable-declarators</a></span> <span class="terminal">;</span> </span></span><span class="grammar-production"><span class="name"><a name="field-modifiers"></a>field-modifiers</span> : <span class="rhs"><span class="non-terminal"><a href="17.4.htm#field-modifier">field-modifier</a></span> </span><span class="rhs"><span class="non-terminal"><a href="17.4.htm#field-modifiers">field-modifiers</a></span> <span class="non-terminal"><a href="17.4.htm#field-modifier">field-modifier</a></span> </span></span><span class="grammar-production"><span class="name"><a name="field-modifier"></a>field-modifier</span> : <span class="rhs"><span class="keyword">new</span> </span><span class="rhs"><span class="keyword">public</span> </span><span class="rhs"><span class="keyword">protected</span> </span><span class="rhs"><span class="keyword">internal</span> </span><span class="rhs"><span class="keyword">private</span> </span><span class="rhs"><span class="keyword">static</span> </span><span class="rhs"><span class="keyword">readonly</span> </span><span class="rhs"><span class="keyword">volatile</span> </span></span><span class="grammar-production"><span class="name"><a name="variable-declarators"></a>variable-declarators</span> : <span class="rhs"><span class="non-terminal"><a href="17.4.htm#variable-declarator">variable-declarator</a></span> </span><span class="rhs"><span class="non-terminal"><a href="17.4.htm#variable-declarators">variable-declarators</a></span> <span class="terminal">,</span> <span class="non-terminal"><a href="17.4.htm#variable-declarator">variable-declarator</a></span> </span></span><span class="grammar-production"><span class="name"><a name="variable-declarator"></a>variable-declarator</span> : <span class="rhs"><span class="non-terminal"><a href="9.4.2.htm#identifier">identifier</a></span> </span><span class="rhs"><span class="non-terminal"><a href="9.4.2.htm#identifier">identifier</a></span> <span class="terminal">=</span> <span class="non-terminal"><a href="19.6.htm#variable-initializer">variable-initializer</a></span> </span></span><span class="grammar-production"><span class="name"><a name="variable-initializer"></a>variable-initializer</span> : <span class="rhs"><span class="non-terminal"><a href="14.14.htm#expression">expression</a></span> </span><span class="rhs"><span class="non-terminal"><a href="19.6.htm#array-initializer">array-initializer</a></span> </span></span></span><span class="locator">
Paragraph 2</span><span class="paragraph"><span class="sentence"><span class="sentence-number">1</span> <a name="P2S1"></a>A <span class="non-terminal"><a href="17.4.htm#field-declaration">field-declaration</a></span> may include a set of attributes (<a href="24.htm">§24</a>), a new modifier (<a href="17.2.2.htm">§17.2.2</a>), a valid combination of the four access modifiers (<a href="17.2.3.htm">§17.2.3</a>), and a static modifier (<a href="17.4.1.htm">§17.4.1</a>).</span> <span class="sentence"><span class="sentence-number">2</span> <a name="P2S2"></a>In addition, a <span class="non-terminal"><a href="17.4.htm#field-declaration">field-declaration</a></span> may include a readonly modifier (<a href="17.4.2.htm">§17.4.2</a>) or a volatile modifier (<a href="17.4.3.htm">§17.4.3</a>), but not both The attributes and modifiers apply to all of the members declared by the <span class="non-terminal"><a href="17.4.htm#field-declaration">field-declaration</a></span>.</span> <span class="sentence"><span class="sentence-number">3</span> <a name="P2S3"></a>It is an error for the same modifier to appear multiple times in a field declaration.</span> </span><span class="locator">
Paragraph 3</span><span class="paragraph"><span class="sentence"><span class="sentence-number">1</span> <a name="P3S1"></a>The type of a <span class="non-terminal"><a href="17.4.htm#field-declaration">field-declaration</a></span> specifies the type of the members introduced by the declaration.</span> <span class="sentence"><span class="sentence-number">2</span> <a name="P3S2"></a>The type is followed by a list of <span class="non-terminal"><a href="17.4.htm#variable-declarator">variable-declarator</a></span>s, each of which introduces a new member.</span> <span class="sentence"><span class="sentence-number">3</span> <a name="P3S3"></a>A <span class="non-terminal"><a href="17.4.htm#variable-declarator">variable-declarator</a></span> consists of an identifier that names that member, optionally followed by an "=" token and a <span class="non-terminal"><a href="19.6.htm#variable-initializer">variable-initializer</a></span> (<a href="17.4.5.htm">§17.4.5</a>) that gives the initial value of that member.</span> </span><span class="locator">
Paragraph 4</span><span class="paragraph"><span class="sentence"><span class="sentence-number">1</span> <a name="P4S1"></a>The type of a field must be at least as accessible as the field itself (<a href="10.5.4.htm">§10.5.4</a>).</span> </span><span class="locator">
Paragraph 5</span><span class="paragraph"><span class="sentence"><span class="sentence-number">1</span> <a name="P5S1"></a>The value of a field is obtained in an expression using a <span class="non-terminal"><a href="14.5.2.htm#simple-name">simple-name</a></span> (<a href="14.5.2.htm">§14.5.2</a>) or a <span class="non-terminal"><a href="14.5.4.htm#member-access">member-access</a></span> (<a href="14.5.4.htm">§14.5.4</a>).</span> <span class="sentence"><span class="sentence-number">2</span> <a name="P5S2"></a>The value of a non-readonly field is modified using an assignment (<a href="14.13.htm">§14.13</a>).</span> <span class="sentence"><span class="sentence-number">3</span> <a name="P5S3"></a>The value of a non-readonly field can be both obtained and modified using postfix increment and decrement operators (<a href="14.5.9.htm">§14.5.9</a>) and prefix increment and decrement operators (<a href="14.6.5.htm">§14.6.5</a>).</span> </span><span class="locator">
Paragraph 6</span><span class="paragraph"><span class="sentence"><span class="sentence-number">1</span> <a name="P6S1"></a>A field declaration that declares multiple fields is equivalent to multiple declarations of single fields with the same attributes, modifiers, and type.</span> <span class="example">[Example: For example <pre class="code-example">
class A
{
public static int X = 1, Y, Z = 100;
}
</pre>is equivalent to <pre class="code-example">
class A
{
public static int X = 1;
public static int Y;
public static int Z = 100;
}
</pre>end example]</span> </span><span class="ruler"></span><table><tr><td><table align="left" bgcolor="navy"><tr bgcolor="navy"><td><font face="Arial,sans-serif" size="6" color="yellow"><strong>{ JSL }</strong></font></td></tr></table></td></tr><tr><td><font face="Arial,sans-serif" size="2" color="navy"><strong>Jagger Software Ltd</strong></font></td></tr><tr><td><font face="Arial,sans-serif" size="2" color="navy"><strong>Company # 4070126</strong></font></td></tr><tr><td><font face="Arial,sans-serif" size="2" color="navy"><strong>VAT # 762 5213 42</strong></font></td></tr></table><img src="valid-html401.png" align="left" height="31" width="88" alt="Valid HTML 4.01" /><img src="vcss.gif" align="left" height="31" width="88" alt="Valid CSS" /></body></html>⌨️ 快捷键说明
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