implementing generic interfaces in c#

Question

how can we inherit generic interfaces in to a generic class? I have tried below code and getting error message: "Bc' does not implement interface member 'ConsoleApplication3.iB.showval(int, int)". How it could be solved?

interface iB<X, Y> 
{
    void storeval(X p1,Y p2);
    void getval();
}
class Bc<X,Y>:iB<int,int>
{
    private X _dm1;
    private Y _dm2;
    public void storeval(X p1,Y p2) 
    {
        this._dm1 = p1;
        this._dm2 = p2;
    }
    public void getval() 
    {
        Console.WriteLine("{0}\t{1}",this._dm1,this._dm2);
    }
}
class Program
{
    static void Main(string[] args)
    {
        Bc<string, bool> b1 = new Bc<string, bool>();
        b1.storeval("AppScienti",true);
        b1.getval();
        Console.ReadKey();
    }
}

Answer 1

Your code is not inheriting a generic interface - it inherits a fully defined instance of a generic interface.

Since you inherit iB<int,int> , you need to implement

public void storeval(int p1, int p2) {
    ...
}

Alternatively, you could inherit iB<X,Y> , in which case your implementation of the interface would have worked:

class Bc<X,Y> : iB<X,Y> {
    ...
}

In either case, the parameters of the interface methods dependent on type parameters of the generic interface need to match the type parameters that you specify when inheriting the interface.

Answer 2

With class Bc<X, Y> : iB<int, int> you define a new generic class, with two new generic type parameters, that happens to implement iB<int, int> . It's more clear if you rename them: class Bc<NewX, NewY> : iB<int, int> .

Your two new generic type parameters have nothing to do with the parameters defined by the interface. You can now declare a new Bc<string, bool> variable while the class still implements iB<int, int> .

You'll have to alter your method signature to let it implement iB<int, int>.storeval(int, int) :

public void storeval(int p1, int p2) 

If you change your Bc class to inherit the generic parameters like this:

class Bc<X, Y> : iB<X, Y>

You can instantiate one like this:

var bcInt = new Bc<int, int>();