How to access an object's property through its interface in C#-CodePudding

I have a class A with a property A.A and a class B with a property B.B. Both implement the IC interface that defines the IC.C property, but do not defines A.A or B.B.

I want a method that receive an instance of A or B as a parameter and can access those properties, something like:

void MyMethod(IC obj)
{
    if (obj.GetType().Name.Equals("A"))
    {
        var v = obj.A;    // some code for access A
    }
}

Is that possible? And, is it a good idea? Thanks!

Edited: renaming the interface as IC as suggested by @dmedine.

CodePudding user response：

The best approach would depend on the specifics of what you are trying to do, but here are 2 options:

Pattern matching

void MyMethod(C obj)
{
    if (obj is A objAsA)
    {
        var vA = objAsA.A;
    }

    if (obj is B objAsB)
    {
        var vB = objAsB.B;
    }
}

Reflection

void MyMethod(C obj)
{
    var objType = obj.GetType();
    if (objType.Name.Equals("A"))
    {
        var prop = objType.GetProperty("A");
        var v = prop.GetValue(obj, null);
    }
}

CodePudding user response：

Doing this can, in my opinion, be useful under certain circumstances. For instance, if you have a bunch of objects that inherit from interface IC (always start the name of an interface with I) that have similar but also unique properties/methods (can't wait for the comments to roll in). You can test the type of class that inherits using is. For example, assuming A and B implement IC:

void MyMethod(List<IC> objects)
{
    foreach(IC object in objects) 
    {
        var cProperty = object.CProperty;  // use common property
        if(object is A a)
            var aProperty = a.AProperty;  // if A, use unique property
    }
}

void Foo()
{
    List<IC> cObjects = new();
    cObjects.Add(new A());
    cObjects.Add(new B());
    MyMethod(cObjects);
}