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<p class=2 style='margin-top:0cm;margin-right:0cm;FTEL:8.15pt;
margin-left:21.45pt;FTEL:18.45pt'><span lang=EN-US>using System.Data;</span></p>

<p class=MsoNormal><span style='font-family:宋体'>这项技术非常适合于只读数据，因为多个线程可以访问它，减少了对数据库中数据的载入。但要注意，由于</span><span
lang=EN-US>Events</span><span style='font-family:宋体'>表有可能发生变化，在</span><span
lang=EN-US>Events</span><span style='font-family:宋体'>表发生变化时，必须更新应用程序层</span><span
lang=EN-US>DataSet</span><span style='font-family:宋体'>。稍后会介绍这一内容。</span></p>

<p class=MsoNormal><span style='font-family:宋体'>接下来需要把方法</span><span
lang=EN-US>GetData()</span><span style='font-family:宋体'>添加给</span><span
lang=EN-US>Service1.asmx.cs</span><span style='font-family:宋体'>中的服务：</span></p>

<p class=a6 style='margin-top:8.15pt;margin-right:0cm;FTEL:0cm;
margin-left:21.45pt;FTEL:.0001pt;FTEL:18.45pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [WebMethod]</span></p>

<p class=a6 style='margin-left:21.45pt;FTEL:18.45pt'><span lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
public DataSet GetData()</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt'><span lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
{</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt'><span lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
return (DataSet)</span><span class=MsoCommentReference><span lang=EN-US
style='font-size:8.0pt;display:none;letter-spacing:.2pt'> </span></span><span
lang=EN-US>Application[&quot;ds&quot;];</span></p>

<p class=2 style='margin-top:0cm;margin-right:0cm;FTEL:8.15pt;
margin-left:21.45pt;FTEL:18.45pt'><span lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
}</span></p>

<p class=MsoNormal><span style='font-family:宋体'>上面代码使用与</span><span lang=EN-US>Application_Load()</span><span
style='font-family:宋体'>相同的语法来访问</span><span lang=EN-US>dataset</span><span
style='font-family:宋体'>，这样，就可以简单地将数据转换为正确的类型，并返回。</span></p>

<p class=MsoNormal><span lang=EN-US>AddEvent()</span><span style='font-family:
宋体'>方法稍微有点复杂，从概念上讲，需要做下面的事情：</span></p>

<p class=1 style='margin-left:37.55pt;FTEL:-16.1pt'><span lang=EN-US>●<span
style='font:7.0pt "Times New Roman"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span
style='font-family:宋体'>接受来自客户的事件数据。</span></p>

<p class=1 style='margin-left:37.55pt;FTEL:-16.1pt'><span lang=EN-US>●<span
style='font:7.0pt "Times New Roman"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span
style='font-family:宋体'>使用那些数据创建</span><span lang=EN-US>SQL INSERT</span><span
style='font-family:宋体'>语句。</span></p>

<p class=1 style='margin-left:37.55pt;FTEL:-16.1pt'><span lang=EN-US>●<span
style='font:7.0pt "Times New Roman"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span
style='font-family:宋体'>连接数据库并且执行</span><span lang=EN-US>SQL</span><span
style='font-family:宋体'>语句。</span></p>

<p class=1 style='margin-left:37.55pt;FTEL:-16.1pt'><span lang=EN-US>●<span
style='font:7.0pt "Times New Roman"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span
style='font-family:宋体'>如果添加成功，就需要刷新</span><span lang=EN-US>Application[“ds”]</span><span
style='font-family:宋体'>中的数据。</span></p>

<p class=1 style='margin-left:37.55pt;FTEL:-16.1pt'><span lang=EN-US>●<span
style='font:7.0pt "Times New Roman"'>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span></span><span
style='font-family:宋体'>把成功或失败的通知返回给客户</span><span lang=EN-US>(</span><span
style='font-family:宋体'>如果有必要，允许客户刷新他们的</span><span lang=EN-US>DataSet)</span><span
style='font-family:宋体'>。</span></p>

<p class=MsoNormal><span style='font-family:宋体'>从现在开始，把所有的字段作为字符串来接受：</span></p>

<p class=2 style='margin-top:8.15pt;margin-right:0cm;FTEL:0cm;
margin-left:21.45pt;FTEL:.0001pt;FTEL:18.45pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [WebMethod]</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt'><span lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
public int AddEvent(String eventName, String eventRoom,</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt'><span lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
String eventAttendees, String eventDate)</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt'><span lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
{</span></p>

<p class=2 style='margin-top:0cm;margin-right:0cm;FTEL:8.15pt;
margin-left:21.45pt;FTEL:18.45pt'><span lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
}</span></p>

<p class=MsoNormal><span style='font-family:宋体'>下面声明访问数据库、连接数据库以及执行查询时需要的对象，完成这些工作所使用的代码与</span><span
lang=EN-US>PCSWebApp3</span><span style='font-family:宋体'>中的代码相似</span><span
lang=EN-US>(</span><span style='font-family:宋体'>此外，这里也需要连接字符串，但是并没有给出</span><span
lang=EN-US>)</span><span style='font-family:宋体'>：</span></p>

<p class=a6 style='margin-top:8.15pt;margin-right:0cm;FTEL:0cm;
margin-left:21.45pt;FTEL:.0001pt;FTEL:18.45pt'><a
FTEL="OLE_LINK4"><span lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [WebMethod]</span></a></p>

<p class=a6 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; public int AddEvent(String eventName,
String eventRoom,</span></p>

<p class=a6 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
String eventAttendees, String eventDate)</span></p>

<p class=a6 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; {</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
System.Data.OleDb.OleDbConnection oleDbConnection1;</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
System.Data.OleDb.OleDbDataAdapter daEvents;</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; DataSet ds;</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; oleDbConnection1 =
new System.Data.OleDb.OleDbConnection();</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
oleDbConnection1.ConnectionString = @&quot; ... &quot;;</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; String oleDbCommand
= &quot;INSERT INTO Events (Name, Room, AttendeeList,&quot; +</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
&quot; EventDate) VALUES ('&quot; + eventName + &quot;', '&quot; +</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
eventRoom + &quot;', '&quot; + eventAttendees + &quot;', '&quot; +</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
eventDate + &quot;')&quot;;</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
System.Data.OleDb.OleDbCommand insertCommand =</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
new System.Data.OleDb.OleDbCommand(oleDbCommand,</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
oleDbConnection1);</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
oleDbConnection1.Open();</span></p>

<p class=2 style='margin-left:21.45pt;FTEL:18.45pt;line-height:15.0pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; int queryResult =
insertCommand.ExecuteNonQuery();</span></p>

<p class=a6 style='margin-top:0cm;margin-right:0cm;FTEL:8.15pt;
margin-left:21.45pt;FTEL:18.45pt'><span lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
}</span></p>

<p class=MsoNormal><span style='font-family:宋体'>如以前一样，使用</span><span
lang=EN-US>queryResult</span><span style='font-family:宋体'>保存受查询影响的行数。如果</span><span
lang=EN-US>queryResult</span><span style='font-family:宋体'>的结果是</span><span
lang=EN-US>1</span><span style='font-family:宋体'>，则说明查询成功，然后就可以对数据库进行新的查询，以便刷新</span><span
lang=EN-US>DataSet</span><span style='font-family:宋体'>中的</span><span
lang=EN-US>Events</span><span style='font-family:宋体'>表。在执行更新时，必须把应用程序数据加锁，确保在更新过程中其他线程不可以访问</span><span
lang=EN-US>Application[</span><span style='font-family:宋体'>“</span><span
lang=EN-US>ds</span><span style='font-family:宋体'>”</span><span lang=EN-US>]</span><span
style='font-family:宋体'>。使用</span><span lang=EN-US>Application</span><span
style='font-family:宋体'>对象的</span><span lang=EN-US>Lock()</span><span
style='font-family:宋体'>和</span><span lang=EN-US>Unlock()</span><span
style='font-family:宋体'>方法，可以实现对数据的加锁和解锁：</span></p>

<p class=a6 style='margin-top:8.15pt;margin-right:0cm;FTEL:0cm;
margin-left:21.45pt;FTEL:.0001pt;FTEL:18.45pt'><span
lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [WebMethod]</span></p>

<p class=a6 style='margin-left:21.45pt;FTEL:18.45pt'><span lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
public int AddEvent(String eventName, String eventRoom,</span></p>

<p class=a6 style='margin-left:21.45pt;FTEL:18.45pt'><span lang=EN-US>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
String eventAttendees, String eventDate)</span></p>