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17.5.1 创建DatabaseResourceReader类
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17.5.1 创建DatabaseResourceReader类
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2006-10-13 14:41:00
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<h1 id="divCurrentNode" style="color: #b83507; width: 100%; text-align: left; font-size: 12px; padding-left: 2px">当前章节:<a href='100165506.htm'><font color='red'>17.5.1 创建DatabaseResourceReader类</font></a></h1>
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<div style='float:left;width:49%'>·<a href='100165503.htm'>17.3.5 资源的自动回退</a></div><div style='float:right;width:49%'>·<a href='100165504.htm'>17.4 ASP.NET应用程序的国际化和本地化</a></div><div style='float:left;width:49%'>·<a href='100165505.htm'>17.5 定制的资源读取器</a></div><div style='float:right;width:49%'>·<a href='100165507.htm'>17.5.2 创建DatabaseResourceSet类</a></div><div style='float:left;width:49%'>·<a href='100165508.htm'>17.5.3 创建DatabaseResourceManager类</a></div><div style='float:right;width:49%'>·<a href='100165509.htm'>17.5.4 DatabaseResourceReader的客户应用程序</a></div></div>
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<div id="text"> <link href="css.css" rel="stylesheet" type="text/css" /><h3 style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 0cm; MARGIN-RIGHT: 0cm; FTEL: 8.15pt"><span lang="EN-US">17.5.1 </span><span style="FONT-FAMILY: 黑体">创建</span><span lang="EN-US">DatabaseResourceReader</span><span style="FONT-FAMILY: 黑体">类</span></h3>
<p class="MsoNormal" style="LINE-HEIGHT: 18pt"><span style="FONT-FAMILY: 宋体">类</span><span lang="EN-US">DatabaseResourceReader</span><span style="FONT-FAMILY: 宋体">定义了两个字段，即访问数据库所需要的数据源名</span><span lang="EN-US">dsn</span><span style="FONT-FAMILY: 宋体">和读取器返回的语言。这些字段在这个类的构造函数中被填充。字段</span><span lang="EN-US">language</span><span style="FONT-FAMILY: 宋体">设置为文化名，这个文化名将与</span><span lang="EN-US">CultureInfo</span><span style="FONT-FAMILY: 宋体">对象一起被传送给构造函数。</span></p>
<p class="2" style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US">public class DatabaseResourceReader : IResourceReader</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US">{</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> private string dsn;</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> private string language;</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> </span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> public DatabaseResourceReader(string dsn, CultureInfo culture)</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> {</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> this.dsn = dsn;</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US"> this.language = culture.Name;</span></p>
<p class="2" style="MARGIN-TOP: 0cm; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US"> }</span></p>
<p class="MsoNormal" style="LINE-HEIGHT: 18pt"><span style="FONT-FAMILY: 宋体">资源读取器必须实现接口</span><span lang="EN-US">IResourceReader</span><span style="FONT-FAMILY: 宋体">，这个接口定义了方法</span><span lang="EN-US">Close()</span><span style="FONT-FAMILY: 宋体">和</span><span lang="EN-US">GetEnumerator()</span><span style="FONT-FAMILY: 宋体">，</span><span lang="EN-US">GetEnumerator()</span><span style="FONT-FAMILY: 宋体">返回一个</span><span lang="EN-US">IDictionaryEnumerator</span><span style="FONT-FAMILY: 宋体">，它为资源返回键和值。在</span><span lang="EN-US">GetEnumerator()</span><span style="FONT-FAMILY: 宋体">实现中，将创建一个散列表，其中存储了特定语言所有的键和值。接着，使用</span><span lang="EN-US">System.Data.SqlClient</span><span style="FONT-FAMILY: 宋体">命名空间中的类</span><span lang="EN-US">SqlConnection</span><span style="FONT-FAMILY: 宋体">在</span><span lang="EN-US">SQL Server</span><span style="FONT-FAMILY: 宋体">中访问数据库。</span><span lang="EN-US">Connection.CreateCommand()</span><span style="FONT-FAMILY: 宋体">创建一个</span><span lang="EN-US">SqlCommand</span><span style="FONT-FAMILY: 宋体">对象，用于指定</span><span lang="EN-US">SQL Select</span><span style="FONT-FAMILY: 宋体">语句，以访问数据库中的数据。如果语言设置为</span><span lang="EN-US">de</span><span style="FONT-FAMILY: 宋体">，</span><span lang="EN-US">Select</span><span style="FONT-FAMILY: 宋体">语句就是</span><span lang="EN-US">SELECT [key], [de] FROM Messages</span><span style="FONT-FAMILY: 宋体">。接着，使用</span><span lang="EN-US">SqlDataReader</span><span style="FONT-FAMILY: 宋体">对象从数据库中读取所有的值，并把它们放在散列表中。最后，返回散列表的枚举。</span></p>
<p class="a3" style="MARGIN-TOP: 8.15pt; FTEL: 21.45pt"><span style="FONT-FAMILY: 黑体">注意：</span></p>
<p class="a1" style="FTEL: 21.45pt"><span style="FONT-FAMILY: 楷体_GB2312">有关</span><span lang="EN-US">ADO.NET</span><span style="FONT-FAMILY: 楷体_GB2312">数据访问的更多信息请参阅第</span><span lang="EN-US">21</span><span style="FONT-FAMILY: 楷体_GB2312">章。</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US">public System.Collections.IDictionaryEnumerator GetEnumerator()</span></p>
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