I want to add an observer in my model, i try to generic delegate but here is problem when invoke.
Here is my code and it works when I use 'handler.DynamicInvoke(this)' instead of 'Invoke'
but I know DynamicInvoke is slow... I want to know is here a right way to use Invoke.
public class Model<T>
{
public delegate void UpdatePrototype<T>(T mdl);
private List<UpdatePrototype<T>> listeners = new List<UpdatePrototype<T>>();
public void Bind(UpdatePrototype<T> handler)
{
listeners.Add(handler);
}
public void Sync()
{
foreach(UpdatePrototype<T> handler in listeners)
{
handler.Invoke((T)this); // << ERROR: can not convert Model<T> to T
}
}
public string Name = "Model";
}
public class MyModel : Model<MyModel>
{
public string Name = "MyModel";
}
public class YourModel : Model<YourModel>
{
public string Name = "YourModel";
}
void Main()
{
MyModel mdl = new MyModel();
mdl.Bind(MyUpdate);
mdl.Sync();
YourModel your = new YourModel();
your.Bind(YourUpdate);
your.Sync();
}
void MyUpdate(MyModel mdl)
{
Debug.Log(mdl.Name);
}
void YourUpdate(YourModel mdl)
{
Debug.Log(mdl.Name);
}
＝＝＝＝＝＝＝＝＝＝＝＝
thanks #IVAAAN123 i modify my code as follow.
it is fine for me, although mdl.Sync<MyModel>() has a little odd ;)
public class Model<T>
{
public delegate void UpdatePrototype<T>(T mdl);
private List<UpdatePrototype<T>> listeners = new List<UpdatePrototype<T>>();
public void Bind(UpdatePrototype<T> handler)
{
listeners.Add(handler);
}
public void Sync()
{
foreach(UpdatePrototype<T> handler in listeners)
{
handler.DynamicInvoke(this);
}
}
public void Sync<T>() where T : Model<T>
{
foreach(UpdatePrototype<T> handler in listeners)
{
handler.Invoke((T)this);
}
}
public string Name = "Model";
}
public class MyModel : Model<MyModel>
{
public string Name = "MyModel";
}
public class YourModel : Model<YourModel>
{
public string Name = "YourModel";
}
void Main()
{
MyModel mdl = new MyModel();
mdl.Bind(MyUpdate);
mdl.Sync<MyModel>();
mdl.Sync();
YourModel your = new YourModel();
your.Bind(YourUpdate);
your.Sync<YourModel>();
your.Sync();
}
void MyUpdate(MyModel mdl)
{
Debug.Log(mdl.Name);
}
void YourUpdate(YourModel mdl)
{
Debug.Log(mdl.Name);
}
}
public class Model<T>
{
public delegate void UpdatePrototype<S>(S mdl);
private List<UpdatePrototype<Model<T>>> listeners = new List<UpdatePrototype<Model<T>>>();
public void Bind(UpdatePrototype<Model<T>> handler)
{
listeners.Add(handler);
}
public void Sync()
{
foreach (UpdatePrototype<Model<T>> handler in listeners)
{
handler(this);
}
}
public virtual string Name
{
get
{
return "Model";
}
}
}
public class MyModel : Model<MyModel>
{
public override string Name
{
get
{
return "MyModel";
}
}
}
public class YourModel : Model<YourModel>
{
public override string Name
{
get
{
return "YourModel";
}
}
}
void main()
{
MyModel mdl = new MyModel();
mdl.Bind(MyUpdate);
mdl.Sync();
YourModel your = new YourModel();
your.Bind(YourUpdate);
your.Sync();
}
void MyUpdate(Model<MyModel> mdl)
{
Console.WriteLine("MY MODEL HANDLER");
Console.WriteLine(mdl.Name);
}
void YourUpdate(Model<YourModel> mdl)
{
Console.WriteLine("YOUR MODEL HANDLER");
Console.WriteLine(mdl.Name);
}
Related
I have currently a problem
I have 1 Interface with two types of argument like this
ITestInterface<ArgumentA>
ITestInterface<ArgumentB>
this interface has only the argument as different
I would like to pass this interface to an constructor of a class. sth like this
public class MyClass
{
public ITestInterface<object> MyInterface {get; set;}
public MyClass(ITestInterface<ArgumentA> testInterfaceA){
this.MyInterface = testInterfaceA as ITestInterface<object>;
this.MyTestInterface.SomeEvent += this.OnSubcribe;
}
public MyClass(ITestInterface<ArgumentB> testInterfaceB){
this.MyInterface = testInterfaceB as ITestInterface<object>;
this.MyTestInterface.SomeEvent += this.OnSubcribe;
}
public void OnSubcribe(){
//Work to do here, dont care about what argument the interface has.
}
}
and to call the MyClass constructor I have sth like this:
public List<MyClass> ClassList = new();
public void testMethod(){
var interA = getInterfaceWithArgumentA();
var myClassA = new MyClass(interA);
var interB = getInterfaceWithArgumentB();
var myClassB = new MyClass(interB);
}
So the problem is i am not able to cast the interface argument to object. I dont need to differenciate the argument either. I just want to avoid to have 2 properties of MyInterface like (MyInterfaceA, MyInterfaceB).
I need also to consider that maybe in the future I will have more type of Argument so maybe to have multiple properties like MyInterfaceA, MyInterfaceB, MyInterfaceC and also multiple constructor for each Interfaceargument type would be a mess.
I just thought about have a Baseclass and the ArgumentA and ArgumentB class derived from it so the cast would work but its not like that.
How would I solve this problem ?
Many Thanks
I think you have not provided what getInterfaceWithArgumentB() and getInterfaceWithArgumentA() method doing. I am making few assumption.
To solve your problem Generic will help.
Following is the example of it.
public class MyClass<T>
{
public ITestInterface<T> MyInterface { get; set; }
public MyClass(ITestInterface<T> testInterfaceA)
{
this.MyInterface = testInterfaceA;
this.MyInterface.SomeEvent += MyInterface_SomeEvent;
}
private void MyInterface_SomeEvent(object sender, EventArgs e)
{
Console.WriteLine(sender);
}
}
public class ArgumentA
{
public string Name { get; set; }
}
public class ArgumentB
{
public int Id { get; set; }
}
public interface ITestInterface<T>
{
T Data { get; set; }
event EventHandler SomeEvent;
void OnSomeEvent();
}
public class TestInterface<T> : ITestInterface<T>
{
public T Data { get ; set; }
public event EventHandler SomeEvent;
public void OnSomeEvent()
{
if(SomeEvent != null)
SomeEvent(Data, EventArgs.Empty);
}
}
You can use it like following.
MyClass<ArgumentA> myClass = new MyClass<ArgumentA>(
new TestInterface<ArgumentA>()
{
Data = new ArgumentA() { Name = "test" }
});
MyClass<ArgumentB> myClas2 = new MyClass<ArgumentB>(
new TestInterface<ArgumentB>()
{
Data = new ArgumentB() { Id = 10 }
});
myClas2.MyInterface.OnSomeEvent();
myClass.MyInterface.OnSomeEvent();
UPDATE
class Program
{
static void Main(string[] args)
{
ObservableCollection<MyClass> items = new ObservableCollection<MyClass>();
MyClass<ArgumentA> myClass = new MyClass<ArgumentA>(
new TestInterface<ArgumentA>()
{
Data = new ArgumentA() { Name = "test" }
});
MyClass<ArgumentB> myClas2 = new MyClass<ArgumentB>(
new TestInterface<ArgumentB>()
{
Data = new ArgumentB() { Id = 10 }
});
items.Add(myClass);
items.Add(myClas2);
myClas2.MyInterface.OnSomeEvent();
myClass.MyInterface.OnSomeEvent();
}
}
public class MyClass
{
public ITestInterface MyInterface { get; set; }
}
public class MyClass<T> : MyClass
{
public MyClass(ITestInterface<T> testInterfaceA)
{
this.MyInterface = testInterfaceA;
this.MyInterface.SomeEvent += MyInterface_SomeEvent;
}
private void MyInterface_SomeEvent(object sender, EventArgs e)
{
Console.WriteLine(sender);
}
}
public class ArgumentA
{
public string Name { get; set; }
}
public class ArgumentB
{
public int Id { get; set; }
}
public interface ITestInterface
{
event EventHandler SomeEvent;
void OnSomeEvent();
}
public interface ITestInterface<T> : ITestInterface
{
T Data { get; }
}
public class TestInterface<T> : ITestInterface<T>
{
public T Data { get; set; }
public event EventHandler SomeEvent;
public void OnSomeEvent()
{
if (SomeEvent != null)
SomeEvent(Data, EventArgs.Empty);
}
}
I cant make working the code below.. Do I need other class that impolement my IComponent with paratmeterless consturctor?
public class Program
{
public static void Main()
{
var lazy = new Lazy<IComponent>();
IComponent comp = lazy.Value;
var client = new ComponentClient(comp);
client.Run();
}
}
public interface IComponent
{
void Something();
}
public class LazyComponent : IComponent
{
public Lazy<IComponent> _LazyComponent { get; set ;}
public LazyComponent(Lazy<IComponent> lazyComponent)
{
_LazyComponent = lazyComponent;
}
public void Something()
{
_LazyComponent.Value.Something();
}
}
public class ComponentClient
{
public IComponent _Component { get; set; }
public ComponentClient(IComponent component)
{
_Component = component;
}
public void Run()
{
_Component.Something();
}
}
You need to tell the Lazy how to construct the component, by giving it a factory method.
https://learn.microsoft.com/en-us/dotnet/api/system.lazy-1?view=netframework-4.8
public class Program
{
public static void Main()
{
var lazy = new Lazy<IComponent>(() => new RealComponent());
var lazyComponent = new LazyComponent(lazy);
var client = new ComponentClient(lazyComponent);
client.Run();
}
}
How to use dependency injection for generic interfaces? I want the IDrawView interface to be created in DrawPresenter, and it controls the view.
I do not know what to use, Ninject or something else. I am using WinForms.
Which is better to choose?
class Program
{
static void Main(string[] args)
{
IDrawPresenter prisenter = new DrawPresenter(new DrawWindow());
prisenter.Show();
Console.ReadLine();
}
}
public interface IView
{
void Show();
}
public interface IDrawView : IView
{
object GetGridDraw { get; }
}
public interface IPrisenter<TView> where TView : IView
{
void Show();
}
public interface IDrawPresenter : IPrisenter<IDrawView>
{
object SelectedDraws { get; }
}
public class DrawWindow : IDrawView
{
public object GetGridDraw => 1;
public void Show()
{
Console.WriteLine("Show Window");
}
}
public abstract class BasePresenter<TView> : IPrisenter<TView>
where TView : IView
{
protected BasePresenter(TView view)
{
View = view;
}
protected TView View { get; private set; }
public void Show()
{
View.Show();
}
}
public class DrawPresenter : BasePresenter<IDrawView>, IDrawPresenter
{
public DrawPresenter(IDrawView view): base(view)
{
}
public object SelectedDraws => View.GetGridDraw;
}
Can DI implement this?
IDrawPresenter prisenter = new DrawPresenter();
public DrawPresenter()
{
}
What I need to do for Presenter to manage the form.
Here is what I want to get. But this does not work ...
public class NinjectProgram
{
//Gets the inject kernal for the program.
public static IKernel Kernel { get; protected set; }
}
public class DependencyModule : NinjectModule
{
public override void Load()
{
Bind<IDrawView>().To<DrawWindow>();
}
}
static void Main(string[] args)
{
StandardKernel Kernel = new StandardKernel();
Kernel.Load(new DependencyModule());
IDrawPresenter prisenter = new DrawPresenter();
prisenter.Show();
Console.ReadLine();
}
public abstract class BasePresenter<TView> : IPrisenter<TView>
where TView : IView
{
protected BasePresenter()
{
View = NinjectProgram.Kernel.Get<TView>();
}
protected TView View { get; private set; }
public void Show()
{
View.Show();
}
}
Thank you all, that’s what I wanted to do. Perhaps this will help someone in the future.
static void Main(string[] args)
{
CompositionRoot.Wire(new DependencyModule());
IDrawPresenter prisenter = new DrawPresenter();//kernel.Get<IDrawPresenter>();
prisenter.Show();
Console.ReadLine();
}
public class CompositionRoot
{
private static IKernel _ninjectKernel;
public static void Wire(INinjectModule module)
{
_ninjectKernel = new StandardKernel(module);
}
public static T Resolve<T>()
{
return _ninjectKernel.Get<T>();
}
}
public class DependencyModule : NinjectModule
{
public override void Load()
{
Bind<IDrawView>().To<DrawWindow>();
}
}
public abstract class BasePresenter<TView> : IPrisenter<TView>
where TView : IView
{
protected BasePresenter()
{
View = CompositionRoot.Resolve<TView>();//NinjectProgram.Kernel.Get<TView>();
}
protected TView View { get; private set; }
}
Also include the presenter in the container and resolve it.
public class DependencyModule : NinjectModule {
public override void Load() {
Bind<IDrawView>().To<DrawWindow>();
Bind<IDrawPresenter>().To<DrawPresenter>();
}
}
All its dependencies, if registered, will also be resolved and injected into the presenter
static void Main(string[] args) {
var kernel = new StandardKernel();
kernel.Load(new DependencyModule());
IDrawPresenter presenter= kernel.Get<IDrawPresenter>();
presenter.Show();
Console.ReadLine();
}
The above is based on
public abstract class BasePresenter<TView> : IPrisenter<TView> where TView : IView {
protected BasePresenter(TView view) {
View = view;
}
protected TView View { get; private set; }
public void Show() {
View.Show();
}
}
public class DrawPresenter : BasePresenter<IDrawView>, IDrawPresenter {
public DrawPresenter(IDrawView view): base(view) {
}
public object SelectedDraws => View.GetGridDraw;
}
I'm trying to get notified when the title of a UIViewController changes.
I tried adding an observer to the title of a UIViewController subclass but it never gets triggered. What's strange about this, is that it works on a plain UIViewController. Am I doing something wrong?
Here's a code example explaining my issue (Xamarin.iOS C#):
using System;
using UIKit;
using System.Collections.Generic;
namespace ObserverTests
{
public partial class ViewController : UIViewController
{
List<UIViewController> viewControllers = new List<UIViewController>();
public override void ViewDidLoad()
{
UIViewController controller1 = new UIViewController() { Title = "Controller1" };
UIViewController controller2 = new Test() { Title = "Controller2" };
this.viewControllers.Add(controller1);
this.viewControllers.Add(controller2);
foreach(UIViewController viewController in viewControllers)
{
viewController.AddObserver("title", Foundation.NSKeyValueObservingOptions.New, (changes) =>
{
Console.WriteLine(viewController.Title);
Console.WriteLine("Title Changed!");
});
}
controller1.Title = "TitleChanged1"; // Works
controller2.Title = "TitleChanged2"; // Fails
}
private class Test : UIViewController
{
}
}
}
In Xamarin the best way might be using inheritance and adding such a feature. For this you derive from UIViewController
public class UIObserveTitleChangedViewController : UIViewController
{
public event TitleChangedEvent TitleChanged;
public override string Title
{
get
{
return base.Title;
}
set
{
var oldTitle = base.Title;
if (oldTitle == value)
return;
base.Title = value;
OnTitleChanged(new TitleChangedEventArgs(value, oldTitle));
}
}
protected virtual void OnTitleChanged(TitleChangedEventArgs args)
{
TitleChanged?.Invoke(this, args);
}
#region ctor
public UIObserveTitleChangedViewController() { }
public UIObserveTitleChangedViewController(NSCoder coder) : base(coder) { }
protected UIObserveTitleChangedViewController(NSObjectFlag t) : base(t) { }
protected internal UIObserveTitleChangedViewController(IntPtr handle) : base(handle) { }
public UIObserveTitleChangedViewController(string nibName, NSBundle bundle) : base(nibName, bundle) { }
#endregion
}
and implement missing event types
public delegate void TitleChangedEvent(object sender, TitleChangedEventArgs args);
public class TitleChangedEventArgs : EventArgs
{
public string NewTitle { get; set; }
public string OldTitle { get; set; }
public TitleChangedEventArgs(string newTitle, string oldTitle)
{
NewTitle = newTitle;
OldTitle = oldTitle;
}
}
You can then subscribe to this event and get notified of changes
public partial class ViewController : UIObserveTitleChangedViewController
{
public ViewController(IntPtr handle) : base(handle)
{
this.TitleChanged += ViewController_TitleChanged; // Subscribe to TitleChanged
}
public override void ViewDidLoad()
{
base.ViewDidLoad();
Title = "Some title"; // triggers TitleChanged
Title = "Another new title"; // triggers TitleChanged
}
private void ViewController_TitleChanged(object sender, TitleChangedEventArgs args)
{
Debug.WriteLine("Title changed from {0} to {1}", args.OldTitle, args.NewTitle);
}
}
You could set the title like so and it will work:
controller2.SetValueForKey(new NSString("TitleChangedHAHA"), new NSString("title"));
You could do this. First define a new event argument that will hold the new title when it changes.
public class TitleChangedEventArgs: EventArgs
{
public string Title { get; private set; }
public TitleChangedEventArgs(string title)
{
Title = title;
}
}
In your test class, add a new Event Handler for TitleChanged and override Title to raise an event when the new title for the view controller.
public class Test : UIViewController
{
public event EventHandler<TitleChangedEventArgs> TitleChanged;
public override string Title {
get {
return base.Title;
}
set {
base.Title = value;
OnTitleChanged();
}
}
public virtual void OnTitleChanged()
{
if (TitleChanged != null) {
TitleChanged.Invoke(this, EventArgs.Empty);
}
}
}
and finally in your Main View Controller you can do something like this:
public class ViewController : UIViewController
{
private Test _test;
public override void ViewDidLoad()
{
_test = new Test();
base.ViewDidLoad();
}
public override void ViewWillAppear(bool animated)
{
base.ViewWillAppear(animated);
_test.TitleChanged += Test_TitleChanged;
}
public override void ViewDidDisappear(bool animated)
{
_test.TitleChanged -= Test_TitleChanged;
base.ViewDidDisappear(animated);
}
void Test_TitleChanged(object sender, TitleChangedEventArgs e)
{
Console.WriteLine("Title Changed! " + e.Title);
}
public override void ViewWillDisappear(bool animated)
{
base.ViewWillDisappear(animated);
}
}
The Title property in UIViewController is marked virtual...so as an alternative solution, you could define a BaseViewController class and override Title and call a method in the Setter:
Public class BaseViewController : UIViewController
{
....
public override string Title {
get {
return base.Title;
}
set {
base.Title = value;
OnTitleChanged();
}
}
protected virtual void OnTitleChanged()
{
......
}
}
Then you can override OnTitleChanged on any of your UIViewControllers to have a callback when the Title is changed.
I have the following code for supporting a list of different types :
public enum eType
{
tInt,
tString,
tDateTime
}
public interface ICustomType<out T>
{
T Value { get; }
}
public abstract class DifferentType
{
protected DifferentType(eType type, string mnemonic)
{
Type = type;
Mnemonic = mnemonic;
}
public string Mnemonic { get; private set; }
public eType Type { get; private set; }
}
public class DateTimeType : DifferentType, ICustomType<DateTime>
{
public DateTimeType(DateTime value, string mnemonic)
: base(eType.tDateTime, mnemonic)
{
Value = value;
}
public DateTime Value { get; private set; }
}
public class IntType : DifferentType, ICustomType<int>
{
public IntType(int value, string mnemonic)
: base(eType.tInt, mnemonic)
{
Value = value;
}
public int Value { get; private set; }
}
public class StringType : DifferentType, ICustomType<string>
{
public StringType(string value, string mnemonic)
: base(eType.tString, mnemonic)
{
Value = value;
}
public string Value { get; private set; }
}
public static class UtilValue
{
public static T GetValue<T>(DifferentType customType)
{
return ((ICustomType<T>)customType).Value;
}
}
public class testTypes2
{
public testTypes2()
{
var values = new List<DifferentType> { GetInt(), GetString(), GetDate() };
foreach (var i in values)
{
switch (i.Type)
{
case eType.tInt:
int resInt = UtilValue.GetValue<int>(i);
break;
case eType.tString:
string resString = UtilValue.GetValue<string>(i);
break;
case eType.tDateTime:
DateTime resDateTime = UtilValue.GetValue<DateTime>(i);
break;
}
}
}
private DateTimeType GetDate()
{
return new DateTimeType(new DateTime(2000, 1, 1), "MnemonicDate");
}
private IntType GetInt()
{
return new IntType(5, "MnemonicInt");
}
private StringType GetString()
{
return new StringType("ok", "MnemonicString");
}
}
and would like to avoid the cast at line return ((ICustomType<T>)customType).Value; in the UtilValue class, any idea how I can get rid of that while still keeping the design?
I am not even sure if this cast is expensive to do? My guess is most certainly.
Visitor-pattern example:
interface IDifferentTypeVisitor
{
void Visit(DateTimeType dt);
void Visit(StringType st);
}
class DifferentType
{
public abstract void Accept(IDifferentTypeVisitor visitor);
}
class DateTimeType : DifferentType
{
public void Accept(IDifferentTypeVisitor visitor)
{
visitor.Visit(this);
}
}
class StringType : DifferentType
{
public void Accept(IDifferentTypeVisitor visitor)
{
visitor.Visit(this);
}
}
class SomeVisitor : IDifferentTypeVisitor
{
public void Visit(DateTimeType dt)
{
//DateTime resDateTime = dt.Value; Or similar
}
public void Visit(StringType st)
{
//string resString = st.Value; Or similar
}
}
public class testTypes2
{
public testTypes2()
{
var values = new List<DifferentType> { /* Content */ };
var visitor = new SomeVisitor();
foreach (var i in values)
{
i.Accept(visitor);
}
}
}
In C# 4 with dynamic it's possible to save some code by adding this to DifferentType:
public void Accept(IDifferentTypeVisitor visitor)
{
visitor.Visit((dynamic)this);
}
and then delete all other Accept methods. It hurts performance but it looks better ;-)