Multiple Interface!!!!!!!

[Wallace]

Hai All,

I am having some query in the following sample code... On creating
object for class1 and calling display function, it shows a message box
with "Hai". My question is

1. Which interface's display is called?
2. If I want to give different implementation for each display(), how
can I do that?
3. Again ambiguity occurs, how can differenciate from multiple
inheritance?

interface ITest1
{
void display();
}

interface ITest2
{
void display();
}

class class1 : ITest1, ITest2
{
public void display()
{
MessageBox.Show("Hai");
}
}

someone plz explain the concept here....
Looking forward for the response...
Thanx in advance...

 

[Marc Gravell]

As it stands, your "Hai" display method() will be called regardless of
whether somebody is looking at your object as a class1, an ITest1 or an
ITest2

If you want to provide separate implementations, or you just don't want to
expose a particular interface method on the class's public interface, then
you use explicit interface implementation, like so:

class class1 : ITest1, ITest2 {
public void display() {
MessageBox.Show("Fred");
}
void ITest1.display() {
MessageBox.Show("Barney");
}
void ITest2.display() {
MessageBox.Show("Wilma");
}
}

Here, I will get 3 different messages:
class1 obj = new class1();
obj.display();
((ITest1) obj).display();
((ITest2) obj).display();

Marc

 

[Tom Porterfield]

Hai All,

I am having some query in the following sample code... On creating
object for class1 and calling display function, it shows a message box
with "Hai". My question is

1. Which interface's display is called?
2. If I want to give different implementation for each display(), how
can I do that?
3. Again ambiguity occurs, how can differenciate from multiple
inheritance?

interface ITest1
{
void display();
}

interface ITest2
{
void display();
}

class class1 : ITest1, ITest2
{
public void display()
{
MessageBox.Show("Hai");
}
}

someone plz explain the concept here....
Looking forward for the response...
Thanx in advance...

It doesn't matter from a pure implementation standpoing. You can, if you
want do explicit interface implementation and provide two display() methods.
But the contract (the interface) simply states you need to provide for a
display() method, so having only one can satisfy both interfaces that you
are implementing. If requirements are such that you do want a separate
implementation for each interface, that is accomplished as follows:

public void ITest1.display(){...}
public void ITest2.display(){...}

 

[John Duval]

Hi Wallace,
If you run into a situation like this, you can differentiate the
implementation like this:

class class1 : ITest1, ITest2
{
void ITest1.display()
{
MessageBox.Show("ITest1");
}
void ITest2.display()
{
MessageBox.Show("ITest2");
}
}

And you can differentiate the call like this:

class1 x = new class1();
ITest1 a = (ITest1)x;
ITest2 b = (ITest2)x;
a.display();
b.display();

Hope that helps,
John

 

[Wallace]

Hai All,

Thanx for ur explanations!!!!!!!!!

It doesn't matter from a pure implementation standpoing. You can, if you
want do explicit interface implementation and provide two display() methods.
But the contract (the interface) simply states you need to provide for a
display() method, so having only one can satisfy both interfaces that you
are implementing. If requirements are such that you do want a separate
implementation for each interface, that is accomplished as follows:

public void ITest1.display(){...}
public void ITest2.display(){...}