在无法获得控件实例的情况下获取控件值的方法

 1          public   static   string  GetControlValueFromRequest( string  controlId)
 2          {
 3              if  (controlId  ==   null )
 4                  throw   new  ArgumentNullException( " controlId " );
 5              string  requestValue  =   null ;
 6             HttpRequest req  =  HttpContext.Current.Request;
 7              string  eventTarget  =  req.Form[ " __EVENTTARGET " ]  ??   string .Empty;
 8              if  (eventTarget.Equals(controlId, StringComparison.InvariantCultureIgnoreCase))
 9              {
10                 requestValue  =  req.Form[ " __EVENTARGUMENT " ];
11             }
12              if  ( string .IsNullOrEmpty(requestValue))
13              {
14                  foreach  ( string  id  in  req.Form.AllKeys)
15                  {
16                      if  (controlId.Equals(GetFriendlyControlId(id), StringComparison.InvariantCultureIgnoreCase))
17                      {
18                         requestValue  =  req[id];
19                          break ;
20                     }
21                 }
22             }
23              return  requestValue;
24         }
25
26          public   static   string  GetFriendlyControlId( string  renderedControlId)
27          {
28              int  indexOfSeparator  =  renderedControlId.LastIndexOf(GetPageIdSeparator());
29              if  (indexOfSeparator  >=   0 )
30              {
31                 renderedControlId  =  renderedControlId.Substring(indexOfSeparator  +   1 );
32             }
33              return  renderedControlId;
34         }
35
36          private   static   string  GetPageIdSeparator()
37          {
38             Page page  =  HttpContext.Current.CurrentHandler  as  Page;
39              return  page  ==   null   ?   " $ "  : page.IdSeparator.ToString();
40         }
41