I have the following classes:
public abstract class Navigator<T> where T : Navigator.Route
{
public class Route
{
}
}
public class P2PNavigator : Navigator<P2PNavigator.Route>
{
public class Route : Navigator.Route
{
}
}
During compilation I receive two errors.
Inconsistent accessibility: constraint type 'Navigator.Route' is less accessible than Navigator<T>'
Inconsistent accessibility: base class 'Navigator.Route' is less accessible than class 'P2PNavigator.Route'
Everything has public accessibility. What am I missing to make this work? I realise I could ultimately make them all namespace level classes, but I would prefer to have nesting.
EDIT: Thanks to the answers, I found the root cause of the problem was my partial classes weren't defined properly.
public partial abstract class Navigator<T> where T : Navigator.Route
{
}
partial class Navigator // Different to Navigator<T> and implicitly internal.
{
public class Route
{
}
}
Navigator.Route is not the same as Navigator<P2PNavigator.Route>.Route and should be giving you other errors.
Code that specifies types correctly compiles ok:
public abstract class Navigator<T> where T : Navigator<T>.Route
{
public class Route
{
}
}
public class P2PNavigator : Navigator<P2PNavigator.Route>
{
public class Route : Navigator<P2PNavigator.Route>.Route
{
}
}
You probably have some non-generic Navigator class that makes your sample comile with errors you see.
Related
I have following class hierarchy
public class EntityBase<T> where T : EntityBase<T>
{
//nothing interesting here
}
public class Benefit : EntityBase<Benefit>
{
//again, nothing interesting here
}
public class SeasonTicketLoan : Benefit
{
//nothing interesting here
}
Now I have got following interface
public interface IQuery<T> where T : EntityBase<T>
{
}
When I try to build following class I get compilation error
public class EmployeesQuery : IQuery<SeasonTicketLoan>
{
}
I get an error saying SeasonTicketLoan class does not satisfy the constraint.
The Benefit class also should have a generic type - so all parent classes have the "ultimate"/sealed type as their generic type. Only the "ultimate"/sealed types have no generic arguments.
The result is that in all parent classes all way through to the root parent class the generic argument contains the type of the "ultimate"/sealed class and no errors arise.
public class EntityBase<T> where T : EntityBase<T>
{
//nothing interesting here
}
public class Benefit<T> : EntityBase<T> where T : Benefit<T>
{
//again, nothing interesting here
}
public sealed class SeasonTicketLoan : Benefit<SeasonTicketLoan>
{
//nothing interesting here
}
If I have an abstract class nested inside a partial container class nested inside another class, how can I derive classes from the base class? I would think the following would work, but it says BaseClass isn't accessible due to protection level. I need the derived classes to be private though.
And before anyone tells me what a bad structure this is, this is why I might need it.
class SingletonClass
{
public static partial class ContainerClass
{
abstract class BaseClass
{
}
}
}
static partial class ContainerClass
{
class DerivedClass : BaseClass
{
}
}
You code does not compile because there are two different ContainerClass types. One is a "normal" class and the other is nested in SingletonClass. If there are no namespace involved then the full name of the first is SingletonClass.ContainerClass while the full name of the second is ContainerClass (i.e., two different types).
To do what you want you need to make SingletonClass partial also:
partial class SingletonClass
{
public static partial class ContainerClass
{
abstract class BaseClass
{
}
}
}
partial class SingletonClass
{
public static partial class ContainerClass
{
class DerivedClass : BaseClass
{
}
}
}
I'm trying to create an object of RecipeManager in mainForm but I get this error:
Inconsistent accessibility: base class
'Assign_1.ListManager<Assign_1.Recipe>' is less accessible than class
'Assign_1.Managers.RecipeManager'
RecipeManager:
public class RecipeManager : ListManager<Recipe>
{
public RecipeManager()
{
}
}
ListManager:
public class ListManager<T> : IListManager<T>
{
protected List<T> m_list;
public ListManager()
{
m_list = new List<T>();
}
public int Count
{
get { return m_list.Count; }
}
I have another manager class that works fine:
public class AnimalManager : ListManager<Animal>
{
private int startID =100;
public AnimalManager()
{
}
I have all Manager classes in a folder called Managers
Generic class is as accessible as least accessible of all parameter. So most likely Recipe class is not public.
Fix: make sure to declare Recipe as public explicitly.
Note that omitting accessibility is most likely reason of class not being public - check out What are the Default Access Modifiers in C#? for defaults.
class Recipe { ... {
means
internal class Recipe {....}
I am having trouble with XML serialization for members that use generics. The following is what my basic class structure looks like (and I want to use the default XML serialization, not overload IXmlSerializable in every class):
public class MyClassToSerialize
{
public Problem<int> Problem;
}
public class MyOtherClassToSerialize
{
public Problem<string> Problem;
}
public abstract class Problem<T>
{
}
public class ProblemImplementationOne<T> : Problem<T>
{
}
public class ProblemImplementationTwo<T> : Problem<T>
{
}
Now here is what I tried:
[XmlInclude(typeof(ProblemImplementationOne<T>))]
[XmlInclude(typeof(ProblemImplementationTwo<T>))]
public abstract class Problem<T>
{
}
This doesn't work: it gives a compile error on the <T> parameter used in the attributes. The following (obviously) doesn't work as well, because it doesn't give enough information for serializing:
[XmlInclude(typeof(ProblemImplementationOne<>))]
[XmlInclude(typeof(ProblemImplementationTwo<>))]
public abstract class Problem<T>
{
}
This gives the error at serializing: "Generic type definition cannot be used in serialization. Only specific generic types can be used."
Does anyone know an easy solution to this problem?
Something like this, depending on the actual runtime type of the Problem properties in the objects you're serializing:
[XmlInclude(typeof(ProblemImplementationOne<int>))]
[XmlInclude(typeof(ProblemImplementationTwo<int>))]
public class MyClassToSerialize
{
public Problem<int> Problem;
}
[XmlInclude(typeof(ProblemImplementationOne<string>))]
[XmlInclude(typeof(ProblemImplementationTwo<string>))]
public class MyOtherClassToSerialize
{
public Problem<string> Problem;
}
Is there any (technical) reason that C# requires all generic type parameters to be declared with their enclosing class' names?
For example, I'd like to declare this:
public class FruitCollection<TFruit> : FoodCollection<TFoodGroup>
where TFruit : IFood<TFoodGroup>
where TFoodGroup : IFoodGroup { }
public class AppleCollection : FruitCollection<Apple> { }
public class TomatoCollection : FruitCollection<Tomato> { }
TFruit is an IFood<TFoodGroup>, so TFoodGroup must be defined if TFruit is provided, even though I haven't explicitly declared it.
Instead, I must do this:
public class FruitCollection<TFoodGroup, TFruit> : FoodCollection<TFoodGroup>
where TFruit : IFood<TFoodGroup>
where TFoodGroup : IFoodGroup { }
// Anything other than FruitGroup is an error when combined with Apple
public class AppleCollection : FruitCollection<FruitGroup, Apple> { }
// Anything other than VegetableGroup is an error when combined with Tomato
public class TomatoCollection : FruitCollection<VegetableGroup, Tomato> { }
The second method works just fine and prevents any invalid combinations from compiling, but it starts getting messy as more and more needless generic type declarations are added to the parameters list.
The other definitions in the set are:
public interface IFoodGroup { }
public class FruitGroup : IFoodGroup { }
public class VegetableGroup : IFoodGroup { }
public interface IFood<TFoodGroup> where TFoodGroup : IFoodGroup { }
public class Apple : IFood<FruitGroup> { }
public class Tomato : IFood<VegetableGroup> { }
public abstract class FoodCollection<TFoodGroup> where TFoodGroup : IFoodGroup { }
Suppose I define:
public class Wompom : IFood<VegetableGroup>, IFood<FruitGroup>
{
}
What would FruitCollection<Wompom> mean?
When everything is specified explicitly:
The compiler doesn't have to perform as much complicated reasoning
The language doesn't have to perform as many complicated rules
You can't get into as many odd, impossible situations