How to call an interface in C#

Question

interface ISample
{
    int fncAdd();
}

class ibaseclass
{
    public int intF = 0, intS = 0;
    int Add()
    {
        return intF + intS;
    }
}
class iChild : ibaseclass, ISample
{
    int fncAdd()
    {
        int intTot = 0;
        ibaseclass obj = new ibaseclass();
        intTot = obj.intF;
        return intTot;
    }
}

I want to call ISample in static void Main(string[] args) but I dont know how to do that. Could you please tell me how?

According to your question, I really don't think you have grasped the purpose of an interface. — Øyvind Bråthen, Mar 14 '11 at 09:42
As mentioned above, I don't think you know what interfaces are. See this http://msdn.microsoft.com/en-us/library/87d83y5b%28v=vs.80%29.aspx — Fishcake, Mar 14 '11 at 09:45

score 10 · Answer 1 · edited May 23 '17 at 11:58

An interface cannot be instantiated by itself. You can't just call an interface. You need to instantiate a class that actually implements the interface.

Interfaces don't and can't do anything by themselves.

For example:

ISample instance = new iChild(); // iChild implements ISample
instance.fncAdd();

The following questions provide more detailed answers about this:

score 2 · Answer 2 · answered Mar 14 '11 at 09:43

2

You can't "call" interface or create instance of it.

What you can do is have your class implement the interface then use its method fncAdd.

answered Mar 14 '11 at 09:43

Shadow Wizard Says No More War

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score 2 · Answer 3 · answered Mar 14 '11 at 09:46

2

Do you mean?:

static void Main(string[] args)
{
    ISample child = new iChild();
    child.fncAdd();
}

Although, as stated by others the code doesn't seem like it's using inheritance correctly.

answered Mar 14 '11 at 09:46

MattC

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How to call an interface in C#

3 Answers3