C# 2.0 Events, Indexers, and Properties

PowerDesigner represents C# events, indexers, and properties as standard UML attributes with additional properties as follows:

Events – stereotype <<Event>> with one or two linked operations representing the add and/or remove handlers
Indexers – stereotype <<Indexer>> with one or two linked operations representing the get and/or set accessors
Properties – stereotype <<Property>> with one or two linked operations representing the get and/or set accessors. In addition, you should note that:
- The visibility of the property is defined by the visibility of the get accessor operation if any, otherwise by that of the set accessor operation.
- When an attribute becomes a property, an implementation attribute is automatically created to store the property value. The implementation attribute is not persistent and has a private visibility. It has the stereotype <<PropertyImplementation>> and has the same name than the property but starting with a lowercase character. If the property name already starts with a lower case its first character will be converted to uppercase.
- The implementation attribute can be removed for properties not needing it. (calculated properties for instance)
- If the boolean-valued extended attribute Extern is set to true, no operations should be linked to the property.
- When a property declaration includes an extern modifier, the property is said to be an external property. Because an external property declaration provides no actual implementation, each of its accessor-declarations consists of a semicolon.

Event Example

The following example shows the Button class, which contains three events:

Property Example

In the following example, class Employee contains 2 properties. The Setter operation has been removed for property TimeReport:

{
 public class Employee
 {
  private int _Function;
  private int _TimeReport;
  // Property Function
  private int Function
  {
   get
   {
     return _Function;
    }
   set
   {
     if (this._Function != value)
      this._Function = value;
    }
  }
  // Property TimeReport
  private int TimeReport
  {
   get
   {
     return _TimeReport;
    }
  }
 }

Indexer Example

In the following example, class Person contains indexer attribute Item. The parameter used to sort the property is String Name:

public class Person
{
 private Hashtable _childAges;
 // Indexer Item
 private int this[String name]
 {
  get
  {
   return (int)_ChildAges[name];
  }
  set
  {
    _ChildAges[name] = value;
  }
 }
}
Person someone;
someone ["Alice"] = 3;
someone ["Elvis"] = 5;