C# director support added

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@9102 626c5289-ae23-0410-ae9c-e8d60b6d4f22

SWIG/Examples/csharp/extend/runme.cs

@@ -0,0 +1,77 @@
+// This file illustrates the cross language polymorphism using directors.
+
+using System;
+
+// CEO class, which overrides Employee::getPosition().
+
+class CEO : Manager {
+  public CEO(String name) : base(name) {
+  }
+  public override String getPosition() {
+    return "CEO";
+  }
+  // Public method to stop the SWIG proxy base class from thinking it owns the underlying C++ memory.
+  public void disownMemory() {
+    swigCMemOwn = false; 
+  } 
+}
+
+
+public class runme
+{
+  static void Main() 
+  {
+    // Create an instance of CEO, a class derived from the C# proxy of the 
+    // underlying C++ class. The calls to getName() and getPosition() are standard,
+    // the call to getTitle() uses the director wrappers to call CEO.getPosition().
+
+    CEO e = new CEO("Alice");
+    Console.WriteLine( e.getName() + " is a " + e.getPosition() );
+    Console.WriteLine( "Just call her \"" + e.getTitle() + "\"" );
+    Console.WriteLine( "----------------------" );
+
+    // Create a new EmployeeList instance.  This class does not have a C++
+    // director wrapper, but can be used freely with other classes that do.
+
+    using (EmployeeList list = new EmployeeList()) {
+
+    // EmployeeList owns its items, so we must surrender ownership of objects we add.
+    e.disownMemory();
+    list.addEmployee(e);
+    Console.WriteLine( "----------------------" );
+
+    // Now we access the first four items in list (three are C++ objects that
+    // EmployeeList's constructor adds, the last is our CEO). The virtual
+    // methods of all these instances are treated the same. For items 0, 1, and
+    // 2, all methods resolve in C++. For item 3, our CEO, getTitle calls
+    // getPosition which resolves in C#. The call to getPosition is
+    // slightly different, however, because of the overidden getPosition() call, since
+    // now the object reference has been "laundered" by passing through
+    // EmployeeList as an Employee*. Previously, C# resolved the call
+    // immediately in CEO, but now C# thinks the object is an instance of
+    // class Employee. So the call passes through the
+    // Employee proxy class and on to the C wrappers and C++ director,
+    // eventually ending up back at the C# CEO implementation of getPosition().
+    // The call to getTitle() for item 3 runs the C++ Employee::getTitle()
+    // method, which in turn calls getPosition(). This virtual method call
+    // passes down through the C++ director class to the C# implementation
+    // in CEO. All this routing takes place transparently.
+
+    Console.WriteLine( "(position, title) for items 0-3:" );
+
+    Console.WriteLine( "  " + list.get_item(0).getPosition() + ", \"" + list.get_item(0).getTitle() + "\"" );
+    Console.WriteLine( "  " + list.get_item(1).getPosition() + ", \"" + list.get_item(1).getTitle() + "\"" );
+    Console.WriteLine( "  " + list.get_item(2).getPosition() + ", \"" + list.get_item(2).getTitle() + "\"" );
+    Console.WriteLine( "  " + list.get_item(3).getPosition() + ", \"" + list.get_item(3).getTitle() + "\"" );
+    Console.WriteLine( "----------------------" );
+
+    // The using statement ensures the EmployeeList.Dispose() will be called, which will delete all the Employee*
+    // items it contains. The last item is our CEO, which gets destroyed as well.
+    }
+    Console.WriteLine( "----------------------" );
+
+    // All done.
+
+    Console.WriteLine( "C# exit" );
+  }
+}