Need help deciding how to structure a C# application that creates products that share similarities but have their differences

Question

I'm having a bit of a mental block trying to figure out the best architecture for this program and need some help.

I'm writing a C# application that creates what we'll call "Views". A view is basically an object which accepts some data as input and spits out another object as output.

Here is the code I'm envisioning:

ViewResponse response;
ViewRequest request;

request = new CustomerViewRequest();
request.Translations = GetTranslations(); // generic to Request
request.CustomerViewAsOfDate = new DateTime(2014,1,1); // specific to CustomerViewRequest

response = ViewCreator.CreateView(request);
Console.WriteLine(response.ViewCreatedSuccessfully); // generic to Response
Console.WriteLine((CustomerViewResponse)response.SomeCustomerViewSpecificProperty); // specific to CustomerViewResponse

request = new BKLedgerViewRequest();
request.Translations = GetTranslations(); // generic to Request
request.EAAnalysisData = GetEAAnalysisData(); // specific to BKLedgerViewRequest

response = ViewCreator.CreateView(bkRequest);
Console.WriteLine(response.ViewCreatedSuccessfully); // generic to Response
Console.WriteLine((BKLedgerViewResponse)response.SomeBKLedgerViewSpecificProperty); // specific to BKLedgerViewResponse

Answer 1

As I look at your code, it seems like the key to accomplishing what you want is just to understand object-oriented coding, inheritance, covariance, and contravariance. I did a re-factor of your code below that compiles and generally does what you are looking for based on using a base class for ViewRequest and ViewResponse.

When you instantiate the objects, using the more specific types of CustomerViewRequest (for example) gives you an object that you can treat as either a ViewRequest or a CustomerViewRequest, depending on your needs.

class Class6
{
    public object GetTranslations() { return null; }
    public object GetEAAnalysisData() { return null; }

    public void DoStuff()
    {
        CustomerViewRequest cvRequest = new CustomerViewRequest();
        cvRequest.Translations = GetTranslations(); // generic to Request
        cvRequest.CustomerViewAsOfDate = new DateTime(2014, 1, 1); // specific to CustomerViewRequest

        CustomerViewResponse cvResponse = ViewCreator.CreateViewResponse<CustomerViewResponse>(cvRequest);
        Console.WriteLine(cvResponse.ViewResponseCreatedSuccessfully); // generic to Response
        Console.WriteLine(cvResponse.SomeCustomerViewSpecificProperty); // specific to CustomerViewResponse

        BKLedgerViewRequest bkRequest = new BKLedgerViewRequest();
        bkRequest.Translations = GetTranslations(); // generic to Request
        bkRequest.EAAnalysisData = GetEAAnalysisData(); // specific to BKLedgerViewRequest

        BKLedgerViewResponse bkResponse = ViewCreator.CreateViewResponse<BKLedgerViewResponse>(bkRequest);
        Console.WriteLine(bkResponse.ViewResponseCreatedSuccessfully); // generic to Response
        Console.WriteLine(bkResponse.SomeBKLedgerViewSpecificProperty); // specific to BKLedgerViewResponse
    }
}

class ViewRequest
{
    public object Translations { get; set; }

}
class ViewResponse
{
    public bool ViewResponseCreatedSuccessfully { get; set; }
}
class CustomerViewRequest : ViewRequest
{
    public DateTime CustomerViewAsOfDate { get; set; }
}

class CustomerViewResponse : ViewResponse
{
    public string SomeCustomerViewSpecificProperty { get; set; }
}

static class ViewCreator
{
    public static T CreateViewResponse<T>(ViewRequest request)
        where T : ViewResponse, new()
    {
        return new T();
    }
}
class BKLedgerViewResponse : ViewResponse
{
    public int SomeBKLedgerViewSpecificProperty { get; set; }
}

class BKLedgerViewRequest : ViewRequest
{
    public object EAAnalysisData { get; set; }
}