From the documentation of a bound API I'm using:
overrideClassNames
Use this to use specific subclasses instead of the default PSPDF*
classes. e.g. add an entry of [PSPDFAnnotationParser class] /
[MyCustomAnnotationParser class] as key/value pair to use the custom
subclass. (MyCustomAnnotationParser must be a subclass of
PSPDFAnnotationParser) Throws an exception if the overriding class is
not a subclass of the overridden class. Note: does not get serialized
when saved to disk.
#property (nonatomic, strong) NSDictionary *overrideClassNames
Here's what I tried but doesn't work. Appearently not strings are required but actual types or something. How can I use this in MonoTouch?
var oClassDic = new NSMutableDictionary();
oClassDic.Add(new NSString("[PSPDFAnnotationParser class]"), new NSString("[PSPDFKitAnnotationParser class]"));
oDoc.OverrideClassNames = oClassDic;
The PSPDFKitAnnotationParser I created like this:
[Register("PSPDFKitAnnotationParser")]
public class PSPDFKitAnnotationParser : PSPDFAnnotationParser
{
public PSPDFKitAnnotationParser () : base()
{
}
public PSPDFKitAnnotationParser (PSPDFDocumentProvider provider) : base(provider)
{
}
public PSPDFKitAnnotationParser (IntPtr handle) : base(handle)
{
}
public PSPDFKitAnnotationParser (NSObjectFlag t) : base(t)
{
}
public PSPDFKitAnnotationParser (NSCoder coder) : base(coder)
{
}
MonoTouch's own bindings generally hides the class and replace them with, the more .NETy, System.Type.
However the MonoTouch.ObjCRuntime.Class type exists and can also be used. If the native code expects class instances then you should be able to do something like:
var oClassDic = new NSMutableDictionary();
oClassDic.Add(new Class("PSPDFAnnotationParser"), new Class("PSPDFKitAnnotationParser"));
oDoc.OverrideClassNames = oClassDic;
You might have to tweak this a bit since a Class instance is not an NSObject, it's a NativeObject in MonoTouch, so you might have to go one level deeper and use the Handle properties (IntPtr) when adding values/keys to your dictionary.
Following #poupou answer this might work, I have not tested it this is what you have to do, It Works (TM)
var oClassDic = new NSMutableDictionary();
var key = new Class("PSPDFAnnotationParser");
var val = new Class("PSPDFKitAnnotationParser");
IntPtr selSetObjectForKey = Selector.GetHandle ("setObject:forKey:");
Messaging.void_objc_msgSend_IntPtr_IntPtr (oClassDic.Handle, selSetObjectForKey, val.Handle, key.Handle);
oDoc.OverrideClassNames = oClassDic;
Selector setObject: forKey: expects an ObjC id type on both params
"id" its just a special type that can hold a pointer to any object you can construct with ObjC
So this should work :)
Hope this helps
Alex
Related
I came across a lot of code in our company codebase with the following structure
class Base
{
public Base (var a, var b)
{
base_a = a;
base_b = b;
}
var base_a;
var base_b;
}
class Derived:Base
{
publc Derived (var a,b,c,d): base (a,d)
{
der_c = c;
der_d = d;
}
var der_c;
var der_d;
var der_e;
}
class Ref
{
Base _ref;
public Ref( var a,b,c,d)
{
_ref = new Derived (a,b,c,d)
}
public void method( )
{
_ref.der_e = 444; // won't compile
}
}
What is the correct way to initialize der_e ? What is the advantages of having a reference of base class and using an object derived class for _ref ? Just the fact that using a base class reference can hold multiple derived class objects ? If that's the case, should all the member variables of derived class be initialized during construction itself (like this: _ref = new Derived (a,b,c,d) ). What if I want to initialize _ref.der_e later in a method ? I know I can do this (var cast_ref = _ref as Derived; cast_ref.der_e = 444) but this look doesn't seem to the best practice. What is the idea of having such a structure and what is the correct of initializing a member of a derived class object after it has been constructed ?
Those are too many questions in a single post.
What is the correct way to initialize der_e ?
For initializing der_e you will have to have Reference of Derived class as it knows about the der_e property and not Base class.
What is the advantages of having a reference of base class and using
an object derived class for _ref ?
Yes that's called Polymorphism which is the essence of Object Oriented Programming. It allows us to hold various concrete implementations without knowing about the actual implementation.
If that's the case, should all the member variables of derived class
be initialized during construction itself (like this: _ref = new
Derived (a,b,c,d) )
There is no such rule. It depends on your scenario. If the values are not meant to be changed after the creation of the object and the values are known before hand during construction of the object then they should be initialized during construction.
Again if there are various scenarios like sometimes values are known and sometimes not then there can be Overloaded Constructors, which take different arguments.
What if I want to initialize _ref.der_e later in a method ?
That is perfectly fine, it depends on what you are trying to achieve. The question is not a concrete one but an abstract one in which it is difficult to comment on what you are trying to achieve.
I know I can do this (var cast_ref = _ref as Derived; cast_ref.der_e =
444) but this look doesn't seem to the best practice.
I am sharing some Java code which is similar to C# as I am from Java background
//This class knows about Base and nothing about the Derived class
class UserOfBase{
Base ref;
//Constructor of UserOfBase gets passed an instance of Base
public UserOfBase(Base bInstance){
this.ref = bInstance;
}
//Now this class should not cast it into Derived class as that would not be a polymorphic behavior. In that case you have got your design wrong.
public void someMethod(){
Derived derivedRef = (Derived)ref; //This should not happen here
}
}
I am sharing some references which would help you with this, as I think the answer can be very long to explain.
Factory Pattern
Dependency Injection
Head First Design Patterns
Posts on SO regarding polymorphism
You can create a constructor in your derived class and map the objects or create an extension method like this:
public static class Extensions
{
public static void FillPropertiesFromBaseClass<T1, T2>(this T2 drivedClass, T1 baseClass) where T2 : T1
{
//Get the list of properties available in base class
System.Reflection.PropertyInfo[] properties = typeof(T1).GetProperties();
properties.ToList().ForEach(property =>
{
//Check whether that property is present in derived class
System.Reflection.PropertyInfo isPresent = drivedClass.GetType().GetProperty(property.Name);
if (isPresent != null && property.CanWrite)
{
//If present get the value and map it
object value = baseClass.GetType().GetProperty(property.Name).GetValue(baseClass, null);
drivedClass.GetType().GetProperty(property.Name).SetValue(drivedClass, value, null);
}
});
}
}
for example when you have to class like this:
public class Fruit {
public float Sugar { get; set; }
public int Size { get; set; }
}
public class Apple : Fruit {
public int NumberOfWorms { get; set; }
}
you can initialize derived class by this code:
//constructor
public Apple(Fruit fruit)
{
this.FillPropertiesFromBaseClass(fruit);
}
When accessing to outlets from my CustomClass : UICollectionViewCell, they are appearing as not initialized and can not set a proper value.
Every example I've seen it uses a plain Class (no XIB) to set the UI.
[Register("CustomCommentCell")]
public partial class CustomCommentCell : UICollectionViewCell
{
public static readonly NSString Identifier = new NSString("CustomCommentCell");
public CustomCommentCell () : base()
{
}
public CustomCommentCell (IntPtr handle) : base (handle)
{
}
public void updateData()
{
this.lblComment.Text = "Test";
}
}
On the other hand, I have registered the Class:
this.tableComments.RegisterClassForCell (typeof(CustomCommentCell),commentCellId);
and have the GetCell properly set.
However, when trying to set the outlets to a specific value, it indicates it is null. (this.lblcomment = null) while it should have been a UILabel initialized.
Any clues?
to create the Custom CollectionViewCell using XIB. do the following
1) create C# class which inherits from UIcollectionViewCell
[Register("MyCustomCell")]
public class MyCustomCell : UICollectionViewCell
{
public static readonly NSString Key = new NSString ("MyCustomCell");
[Export ("initWithFrame:")]
public MyCustomCell(CoreGraphics.CGRect frame) : base (frame)
{
}
public override UIView ContentView {
get {
var arr= NSBundle.MainBundle.LoadNib ("MyCustomCell", this, null);
UIView view =arr.GetItem<UIView> (0);
view.Frame = base.ContentView.Frame;
base.ContentView.AddSubview (view);
return base.ContentView;
}
}
}
2) Add a IphoneView XIB file has the Same Name as that of Class created in step 1
3) Open XIB in XCODE and do the Following Changes
3.1)Select the FileOwner set the Class same name as Step 1
3.2)Select The View Set the Class name UIView
4) Design Your XIB Accordingly
I can't follow quite the problem you are seeing. What is a "Custom XIB outlet"? Why is this question tagged "custom-controls"? Is there some example code or pictures you can show to help explain the problem?
The approach I use for UICollectionViewCell's is the same as I use for UITableViewCell - see the tutorial - http://slodge.blogspot.co.uk/2013/01/uitableviewcell-using-xib-editor.html
Update: From the code you've posted as a comment (not sure if it's complete or not), I think it would be useful for you to follow through that tutorial. There are a few steps to complete including registering the custom class name and including using RegisterNibForCellReuse - one of those will probably fix this for you.
I have subclassed a ViewController that was created via XCode Interface Builder. my subclass is defined like so
public MyViewControllerGeneric<T> : MyViewController{
public MyViewControllerGeneric(IntPtr handle) : base(handle){}
}
I can use Storyboard.InstantiateViewController("MyViewController") to get an instance of MyViewController. However how do I create an instance of MyViewControllerGeneric and pass a handle to it?
Tried
var vc = new MyViewControllerGeneric<MyType>(this.Handle)
var vc = new MyViewControllerGeneric<MyType>(new IntPtr(DateTime.Now.Ticks)
both throw a SigAbort
Any Help highly appreciated.
The IntPtr handle is not something you should be passing in.
Use this constructor instead:
public MyViewControllerGeneric<T> : MyViewController{
public MyViewControllerGeneric() : base(){ }
}
Or this if you need a NIB loaded, depending on your base class:
public MyViewControllerGeneric<T> : MyViewController{
public MyViewControllerGeneric() : base("MyViewControllerGeneric", null){ }
}
I have this interface for using AutoMapper:
public interface IMapper
{
object Map(object source, Type sourceType, Type destinationType);
}
Then for each type of data, I have a different mapper class , for example:
public class UserMapper : IMapper
{
static UserMapper()
{
Mapper.CreateMap<User, UserViewModel>();
Mapper.CreateMap<UserViewModel, User>();
}
public object Map(object source, Type sourceType, Type destinationType)
{
return Mapper.Map(source, sourceType, destinationType);
}
}
Then I have IMapper as one of the parametter in my controller class like this:
public UsersController(IUsersRepository repo, IMapper userMapper)
{....}
I am using Windsor as the IOC for my application and the problem is that I want to register the components, so that when running in UsersController , it use the UserMapper class and if running on ProductsController it will use my ProductMapper class.
My registration code looks something along the line of this:
container.Register(
Component.For<IMapper>()
.ImplementedBy<UsersMapper>()
.Named("usersMapper"),
Component.For<IMapper>()
.ImplementedBy<ProductsMapper>()
.Named("productsMapper"),
Component.For<ProductController>()
.ServiceOverrides(ServiceOverride.ForKey("usersMapper").Eq("productsMapper"))
)
I have done my homework on google and stackoverflow, and i know that I need to use ServicesOverride but I am still stuck on this, could anyone give me a hand please?
Thanks
While svick's solution looks correct to me (I haven't attempted to compile it, though), this scenario is an excellent case for convention-based configuration.
Let's introduce this convention: Each consumer of IMapper will signal the intended role of the mapper by its name. By default, that name will be matched with a type of the same name - only with different casing.
So, constructor parameters could be mapped like this:
userMapper -> UserMapper
productMapper -> ProductMapper
In Castle Windsor, such a configuration might look like this:
container.Register(Classes
.FromThisAssembly()
.Pick()
.WithServiceAllInterfaces()
.WithServiceSelf());
container.Kernel.Resolver.AddSubResolver(
new MapperConvention(container.Kernel));
And the Sub Resolver (where the magic really happens) looks like this:
public class MapperConvention : ISubDependencyResolver
{
private readonly IKernel kernel;
public MapperConvention(IKernel kernel)
{
this.kernel = kernel;
}
public bool CanResolve(CreationContext context,
ISubDependencyResolver contextHandlerResolver,
ComponentModel model,
DependencyModel dependency)
{
return typeof(IMapper).IsAssignableFrom(dependency.TargetType);
}
public object Resolve(CreationContext context,
ISubDependencyResolver contextHandlerResolver,
ComponentModel model,
DependencyModel dependency)
{
var representativeMapperType = typeof(UserMapper);
var concreteMapperType = representativeMapperType.Assembly
.GetExportedTypes()
.Where(t =>
t.Name.Equals(dependency.DependencyKey,
StringComparison.OrdinalIgnoreCase))
.Single();
return this.kernel.Resolve(concreteMapperType);
}
}
This registration works for me:
container.Register(
Component.For<IMapper>()
.ImplementedBy<UserMapper>()
.Named("userMapper"),
Component.For<IMapper>()
.ImplementedBy<ProductMapper>()
.Named("productMapper"),
Component.For<UsersController>()
.ServiceOverrides(ServiceOverride.ForKey<IMapper>().Eq("userMapper")),
Component.For<ProductsController>()
.ServiceOverrides(ServiceOverride.ForKey<IMapper>().Eq("productMapper"))
);
I've a base presenter class:
public abstract class PresenterBase<T> where T : IView
{
//Some code
}
A concrete presenter class that implements this base:
public class RegistrationPresenter : PresenterBase<IRegistration>
{
//Some Code
}
A concrete presenter factory to return the instance of presenter which depends on a specific interface contract:
public class ProductPresenterFactory : PresenterFactoryBase
{
// Some code
public override PresenterBase<IView> GetPresenter(IView view, string name = "")
{
if (view == null && string.IsNullOrEmpty(name))
throw new ArgumentNullException();
return presenter;
}
}
I need to implement the GetPresenter method. The user will put the interface contract, for example of type IRegistration in the above case. This method should figure out the class that implements PresenterBase<IRegistration> and return an instance.
I did not write this with a compiler; I might have made a few mistakes.
You'll first need to get the type of the presenterbase, then we'll scour the assemble for the implementation, then call it's constructor. I'll make some assumptions as written in the code.
var genericType = typeof (PresenterBase<>).MakeGenericType(new[] { view.GetType() });
var allTypes = GetType().Assembly.GetTypes(); // I assume the class is in the same assembly.
var typeToImplement = allTypes.Single(t => t.IsSubclassOf(genericType)); // I assume there is only one implementation for the given type
var constructorToCall = typeToImplement.GetConstructors().First(); // I assume there is one constructor
var presenter = constructorToCall.Invoke(new object[0]); // I assume there is no parameter