can we Trace delegate Call chain by using Delegate object ?

All that you'll be able to obtain from the delegate is its invocation list i.e. the list of methods which will be called when the delegate is invoked.

To track the methods which have been called up to the current point, you need a stack trace:

using System;

using System.Diagnostics;

using System.Threading;

class MyClass

{

public void MethodA(Delegate obj)

{

MethodB(obj);

(obj as Action)();

Thread.Sleep(100);

}

public void MethodB(Delegate obj)

{

MethodC(obj);

(obj as Action)();

Thread.Sleep(100);

}

public void MethodC(Delegate obj)

{

foreach(Delegate d in obj.GetInvocationList())

{

Console.WriteLine(d.Method);

}

Console.WriteLine();

StackTrace st = new StackTrace(true);

for(int i = 0; i< st.FrameCount; i++ )

{

StackFrame sf = st.GetFrame(i);

Console.WriteLine("Method: {0}", sf.GetMethod());

}

class Program

{

static void Main()

{

var mc = new MyClass();

Action d = MyGreeting;

mc.MethodA(d);

Console.ReadKey();

}

static void MyGreeting()

{

Console.WriteLine("Hello");

}

}

The output is :

Void MyGreeting()

Method: Void MethodC(System.Delegate)

Method: Void MethodB(System.Delegate)

Method: Void MethodA(System.Delegate)

Method: Void Main()

Hello

Hello

Notice that the only method in the invocation list is MyGreeting.

However, the stack trace reveals the methods that have been called culminating in MethodC.

Notice also that I've had to add extra code to MethodA and MethodB to avoid them being 'optimized away' by the JIT compiler.

2 Replies

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Vulpes11y ago
All that you'll be able to obtain from the delegate is its invocation list i.e. the list of methods which will be called when the delegate is invoked.

To track the methods which have been called up to the current point, you need a stack trace:

using System;
using System.Diagnostics;
using System.Threading;

class MyClass
{
public void MethodA(Delegate obj)
{
MethodB(obj);
(obj as Action)();
Thread.Sleep(100);
}

public void MethodB(Delegate obj)
{
MethodC(obj);
(obj as Action)();
Thread.Sleep(100);
}

public void MethodC(Delegate obj)
{
foreach(Delegate d in obj.GetInvocationList())
{
Console.WriteLine(d.Method);
}

Console.WriteLine();

StackTrace st = new StackTrace(true);
for(int i = 0; i< st.FrameCount; i++ )
{
StackFrame sf = st.GetFrame(i);
Console.WriteLine("Method: {0}", sf.GetMethod());
}
}
}

class Program
{
static void Main()
{
var mc = new MyClass();
Action d = MyGreeting;
mc.MethodA(d);
Console.ReadKey();
}

static void MyGreeting()
{
Console.WriteLine("Hello");
}
}

The output is :

Void MyGreeting()

Method: Void MethodC(System.Delegate)
Method: Void MethodB(System.Delegate)
Method: Void MethodA(System.Delegate)
Method: Void Main()
Hello
Hello

Notice that the only method in the invocation list is MyGreeting.

However, the stack trace reveals the methods that have been called culminating in MethodC.

Notice also that I've had to add extra code to MethodA and MethodB to avoid them being 'optimized away' by the JIT compiler.
Manish Kumar Choudhary11y ago
Hi ramesh forever,
Read these links it may help you

http://msdn.microsoft.com/en-us/library/bb985537.aspx

http://etutorials.org/Programming/visual-c-sharp/Part+II+Advanced+C/Chapter+6+Delegates+and+Attributes/Using+Delegates/