
This is the Title of the Book, eMatter Edition
Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.
520
|
Chapter 9: Delegates, Events, and Anonymous Methods
return (false);
}
return (false);
}
• A filter to search for any members that are marked with the System.
ObsoleteAttribute
attribute:
private bool ReturnTypeFilter(MemberInfo member, object criteria)
{
object[] attrs = member.GetCustomAttributes(false);
foreach (object attr in attrs)
{
if (attr.ToString( ).Equals("System.ObsoleteAttribute"))
{
return (true);
}
}
return (false);
}
See Also
See Recipe 9.7; see the “Delegate Class” and “Type.FindMembers Method” topics in
the MSDN documentation.
9.9 Observing Additions and Modifications
to a Hashtable
Problem
You have multiple objects that need to observe modifications to a Hashtable. When
an item is added or modified in the
Hashtable, each of these observer objects should
be able to vote to allow or disallow the action. In order for an action to be allowed to
complete, all observer objects must vote to allow the action. If even one observer
object votes to disallow the action, the action is prevented.
Solution
To observe additions and modifications to the ObservableHashtable class (shown in
Example 9-10) object that is registered with this object, use the
HashtableObserver
class implemented in Example 9-11. The ObservableHashtable class is an extension of
the regular
Hashtable class and allows ...