Calling a method with an instance of derived class of derived generic type

Posted by madsbirk on Stack Overflow See other posts from Stack Overflow or by madsbirk
Published on 2013-10-27T21:51:33Z Indexed on 2013/10/27 21:53 UTC
Read the original article Hit count: 333

Filed under:

c#

|

generics

|

polymorphism

Okay, so I have classes

class B<T> : A<T>
class L : K

and a method

void Method(A<K> a) {...}

What I would like to do is this

b = new B<L>();
Method(b); //error

But it is not possible to b to the correct type. Indeed it is not possible to make this cast

A<K> t = new A<L>(); //error

I would really like to not have to change the internals of Method. I have no problems making changes to B and/or L. Do I have any options for making some sort of workaround? I guess it should be possible for Method to execute all of its method calls etc. on b, since B derives from A and L derives from K?

© Stack Overflow or respective owner

Related posts about c#

.NET WebRequest.PreAuthenticate not quite what it sounds like

as seen on West-Wind - Search for 'West-Wind'
I’ve run into the problem a few times now: How to pre-authenticate .NET WebRequest calls doing an HTTP call to the server – essentially send authentication credentials on the very first request instead of waiting for a server challenge first? At first glance this sound like it should be easy:… >>> More
HttpWebRequest and Ignoring SSL Certificate Errors

as seen on West-Wind - Search for 'West-Wind'
Man I can't believe this. I'm still mucking around with OFX servers and it drives me absolutely crazy how some these servers are just so unbelievably misconfigured. I've recently hit three different 3 major brokerages which fail HTTP validation with bad or corrupt certificates at least according to… >>> More
The dynamic Type in C# Simplifies COM Member Access from Visual FoxPro

as seen on West-Wind - Search for 'West-Wind'
I’ve written quite a bit about Visual FoxPro interoperating with .NET in the past both for ASP.NET interacting with Visual FoxPro COM objects as well as Visual FoxPro calling into .NET code via COM Interop. COM Interop with Visual FoxPro has a number of problems but one of them at least got a lot… >>> More
Dynamic Type to do away with Reflection

as seen on West-Wind - Search for 'West-Wind'
The dynamic type in C# 4.0 is a welcome addition to the language. One thing I’ve been doing a lot with it is to remove explicit Reflection code that’s often necessary when you ‘dynamically’ need to walk and object hierarchy. In the past I’ve had a number of ReflectionUtils that used string based expressions… >>> More
Finding a Relative Path in .NET

as seen on West-Wind - Search for 'West-Wind'
Here’s a nice and simple path utility that I’ve needed in a number of applications: I need to find a relative path based on a base path. So if I’m working in a folder called c:\temp\templates\ and I want to find a relative path for c:\temp\templates\subdir\test.txt I want to receive back subdir\test… >>> More

Related posts about generics

Java generics: What is the compiler's issue here?

as seen on Stack Overflow - Search for 'Stack Overflow'
I have the following methods: public <T> T fromJson( Reader jsonData, Class<T> clazz ) { return fromJson( jsonData, (Type)clazz ); } public <T> T fromJson( Reader jsonData, Type clazz ) { ... } The compiler is saying about the first method: type parameters of <T>T… >>> More
Why does NUnit ignore datapoints when using generics in a theory

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm trying to make use of the TheoryAttribute, introduced in NUnit 2.5. Everything works fine as long as the arguments are of a defined type: [Datapoint] public double[,] Array2X2 = new double[,] { { 1, 0 }, { 0, 1 } }; [Theory] public void TestForArbitraryArray(double[,] array) { // ... } It… >>> More
Instantiating generics type in java

as seen on Stack Overflow - Search for 'Stack Overflow'
I would like to create an object of Generics Type in java. Please suggest how can I achieve the same. suppose I have the class declaration as: public class Abc<T> { public static void main(String[] args) { // I want to create an instance of T } } >>> More
.NET converting simple arrays to List Generics

as seen on Stack Overflow - Search for 'Stack Overflow'
This question might seem trivial and also stupid at the first glance, but it is much more than this. I have an array of any type T (T[]) and I want to convert it into a List generic (List<T>). Is there any other way apart from creating a Generic list, traversing the whole array and adding the… >>> More
Instantiating a list of parameterized types, making beter use of Generics and Linq

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm hashing a file with one or more hash algorithms. When I tried to parametrize which hash types I want, it got a lot messier than I was hoping. I think I'm missing a chance to make better use of generics or LINQ. I also don't like that I have to use a Type[] as the parameter instead of limiting… >>> More