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.NET style delegates for VC++ 6

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19 Aug 2003CPOL11 min read 106.5K   556   44  
An implementation of synchronous .NET style delegates in non - .NET VC++ 6.
// cppdelegates.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
#include "delegate.h"

using namespace std;

DECLARE_DELEGATE(Add, (int p1, float p2), (p1, p2))

class A
{
public:
    A() { value = 5; }
    virtual void Fun1(int val, float val2)
    {
        value = val*2*(int)val2;
        cout << "[A::Fun1] " << val << ", " << val2 << endl;
    }
    static void StaticFunc(int val, float val2)
    {
        cout << "[A::StaticFunc] " << val << ", " << val2 << endl;
    }
public:
    int value;
};

class B : public A
{
public:
    void Fun1(int val, float val2)
    {
        value += val*3*(int)val2;
        cout << "[B::Fun1] " << val << ", " << val2 << endl;
    }
};

void GlobalFunc(int val, float val2)
{
    cout << "[GlobalFunc] " << val << ", " << val2 << endl;
}

int main()
{
    // Create class instances
    A a;
    B b;
    // Create an instance of the delegate
    AddDelegate::Delegate del;
    // Add our handlers
    del += AddHandler(&a, A::Fun1); // or del.Add(&a, A::Fun1);
    del += AddHandler(&b, B::Fun1); // or del.Add(&b, B::Fun2);
    del += GlobalFunc;              // or del.Add(GlobalFunc);
    del += A::StaticFunc;           // or del.Add(A::StaticFunc);
    // Invoke the delegate
    del(4, 5);                      // or del.Invoke(4, 5);
    // Print the class values
    cout << "[main] a.value = " << a.value << endl;
    cout << "[main] b.value = " << b.value << endl;
    // Remove some of the handlers
    del -= AddHandler(&a, A::Fun1); // or del.Remove(&a, A::Fun1);
    del -= A::StaticFunc;           // or del.Remove(A::StaticFunc);
    // Invoke the delegate again
    del(4, 5);                      // or del.Invoke(4, 5);
    // Print the class values
    cout << "[main] a.value = " << a.value << endl;
    cout << "[main] b.value = " << b.value << endl;
    return 0;
}

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License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


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