/*
* 1. A multicast delegate is a delegate that has reference to more than one function.
* When you invoke a multicast delegate,all the functions the delegate is pointign to are invoked.
*
* 2. There are 2 approaches to create a multicast delegate. Depending on the approach you use.
* + or += to register a method with the delegate.
* - or -= to un-register a method with the delegate.
*
* 3. Note :: A multicast delegate, invokes the methods in the invocation list, in the same order in which the are added.
*
* 4. If the delegate has a return type other than void and if the delegate is a multicast delegate.
* Only the value of the last invoked method will be returned. Along the same lines.
* If the delegate has an out parameter, the value of the output parameter, will be the value assigned by the last method.
*
* 5. Common interview question - where do we use multicast delegate. ?
* Multicast delegate makes implementation of observe design pattern very simple. Observe design pattern is also called as publish/subscribe design pattern.
*/
static void Main(string[] args)
{
#region 1. Methods with void return type
#region Way One
Console.WriteLine("Invoked by way one:\n");
SampleDelegateVoid del1, del2, del3, del4;
del1 = new SampleDelegateVoid(SampleMethodOneVoid);
del2 = new SampleDelegateVoid(SampleMethodTwoVoid);
del3 = new SampleDelegateVoid(SampleMethodThreeVoid);
del4 = del1 + del2 + del3;
del4();
Console.WriteLine("\n");
del4 = del1 + del2 - del3;
del4();
#endregion
#region Way Two
Console.WriteLine("\nInvoked by way two:\n");
SampleDelegateVoid sDel = new SampleDelegateVoid(SampleMethodOneVoid);
sDel += SampleMethodTwoVoid;
sDel += SampleMethodThreeVoid;
sDel();
Console.WriteLine("\n");
sDel -= SampleMethodThreeVoid;
sDel();
#endregion
#endregion
// A multicast delegate, invokes the methods in the invocation list, in the same order in which the are added.
// If the delegate has a return type other than void and if the delegate is a multicast delegate. Only the value of the last invoked method will be returned. Along the same lines.
#region 2. Methods with any return type, example int.
Console.WriteLine("Delegate with int return type.\n");
SampleDelegateInt sDelInt = new SampleDelegateInt(SampleMethodOneInt);
sDelInt += SampleMethodTwoInt;
sDelInt += SampleMethodThreeInt;
int delegateReturnedValue = sDelInt();
Console.WriteLine("\nDelegate returned value (Third method invoked at last) = {0}.\n", delegateReturnedValue);
sDelInt -= SampleMethodThreeInt;
delegateReturnedValue = sDelInt();
Console.WriteLine("\nDelegate returned value (Third method deleted from invokation list) = {0}.\n", delegateReturnedValue);
#endregion
//A multicast delegate, invokes the methods in the invocation list, in the same order in which the are added.
// If the delegate has an out parameter, the value of the output parameter, will be the value assigned by the last method.
#region 3. Methods having out parameter
Console.WriteLine("Delegate with output parameter.\n");
SampleDelegateOut sDelOut = new SampleDelegateOut(SampleMethodOneOut);
sDelOut += SampleMethodTwoOut;
sDelOut += SampleMethodThreeOut;
int delegateOutputParam = -1;
sDelOut(out delegateOutputParam);
Console.WriteLine("\nDelegate returned ouput value (Third method invoked at last) = {0}.\n", delegateOutputParam);
sDelOut -= SampleMethodThreeOut;
sDelOut(out delegateOutputParam);
Console.WriteLine("\nDelegate returned ouput value (Third method deleted from invocation list) = {0}.\n", delegateOutputParam);
#endregion
Console.ReadKey();
}
/*
* 1. A multicast delegate is a delegate that has reference to more than one function.
* When you invoke a multicast delegate,all the functions the delegate is pointign to are invoked.
*
* 2. There are 2 approaches to create a multicast delegate. Depending on the approach you use.
* + or += to register a method with the delegate.
* - or -= to un-register a method with the delegate.
*
* 3. Note :: A multicast delegate, invokes the methods in the invocation list, in the same order in which the are added.
*
* 4. If the delegate has a return type other than void and if the delegate is a multicast delegate.
* Only the value of the last invoked method will be returned. Along the same lines.
* If the delegate has an out parameter, the value of the output parameter, will be the value assigned by the last method.
*
* 5. Common interview question - where do we use multicast delegate. ?
* Multicast delegate makes implementation of observe design pattern very simple. Observe design pattern is also called as publish/subscribe design pattern.
*/
static void Main(string[] args)
{
#region 1. Methods with void return type
#region Way One
Console.WriteLine("Invoked by way one:\n");
SampleDelegateVoid del1, del2, del3, del4;
del1 = new SampleDelegateVoid(SampleMethodOneVoid);
del2 = new SampleDelegateVoid(SampleMethodTwoVoid);
del3 = new SampleDelegateVoid(SampleMethodThreeVoid);
del4 = del1 + del2 + del3;
del4();
Console.WriteLine("\n");
del4 = del1 + del2 - del3;
del4();
#endregion
#region Way Two
Console.WriteLine("\nInvoked by way two:\n");
SampleDelegateVoid sDel = new SampleDelegateVoid(SampleMethodOneVoid);
sDel += SampleMethodTwoVoid;
sDel += SampleMethodThreeVoid;
sDel();
Console.WriteLine("\n");
sDel -= SampleMethodThreeVoid;
sDel();
#endregion
#endregion
// A multicast delegate, invokes the methods in the invocation list, in the same order in which the are added.
// If the delegate has a return type other than void and if the delegate is a multicast delegate. Only the value of the last invoked method will be returned. Along the same lines.
#region 2. Methods with any return type, example int.
Console.WriteLine("Delegate with int return type.\n");
SampleDelegateInt sDelInt = new SampleDelegateInt(SampleMethodOneInt);
sDelInt += SampleMethodTwoInt;
sDelInt += SampleMethodThreeInt;
int delegateReturnedValue = sDelInt();
Console.WriteLine("\nDelegate returned value (Third method invoked at last) = {0}.\n", delegateReturnedValue);
sDelInt -= SampleMethodThreeInt;
delegateReturnedValue = sDelInt();
Console.WriteLine("\nDelegate returned value (Third method deleted from invokation list) = {0}.\n", delegateReturnedValue);
#endregion
//A multicast delegate, invokes the methods in the invocation list, in the same order in which the are added.
// If the delegate has an out parameter, the value of the output parameter, will be the value assigned by the last method.
#region 3. Methods having out parameter
Console.WriteLine("Delegate with output parameter.\n");
SampleDelegateOut sDelOut = new SampleDelegateOut(SampleMethodOneOut);
sDelOut += SampleMethodTwoOut;
sDelOut += SampleMethodThreeOut;
int delegateOutputParam = -1;
sDelOut(out delegateOutputParam);
Console.WriteLine("\nDelegate returned ouput value (Third method invoked at last) = {0}.\n", delegateOutputParam);
sDelOut -= SampleMethodThreeOut;
sDelOut(out delegateOutputParam);
Console.WriteLine("\nDelegate returned ouput value (Third method deleted from invocation list) = {0}.\n", delegateOutputParam);
#endregion
Console.ReadKey();
}
