instance

问题 Given a really oversimplified example: Class A { B b = new B(); } Class B { //unicorns and what-not //Something happens and I want to let A know //Yet I don't want to return and exit } Is there any way that B can communicate with A without Sockets? By communicate, I mean B sending values to A without A invoking a method on B. EDIT : Thank you for your responses. This following is my follow up question: If I had the following, and method signal() is called simultaneously by 2 instances of B,

问题 I have a gui application I put text into text box1, text box2,and then click on the pushButton , The function return_text_username () in the moduel_b.py be called. Now I can call one instance by lambda1 function and use it in class_b , but I can not call two instants when I click on the pushbutton . **A- I want add lineEdit_2 into lambda method in main.py or add instance_lambda2_password into connect method. **B- I want to edit return_printtext_password (self, txt) in the moduel_b.py to print

问题 I am completely new to django and was a php coder previously, so please bear with me if i am being dumb. I have three models defined in my app, Comprehension, Question, Answer. Each comprehension has multiple questions and answers defined as 'inline' in the Comprehension model. Questions are input directly by the admin, but answers would added automatically from the comprehension. What I want to achieve is, to split the comprehension in to sentences and add each sentence as an answer object

问题 I'm just beginning understanding delegates, I have a class that implemens IDisposable: public class MyClass : IDisposable { public delegate int DoSomething(); public int Zero() {return 0;} public int One() {return 1;} public void Dispose() { // Cleanup } } A method (defined in an another class) that is using MyClass: public class AnotherCLass { public static void UseMyClass(MyClass.DoSomething func) { using (var mc = new MyClass()) { // Call the delegate function mc.func(); // <-------- this

问题 I have a button in my SettingsViewController that when pressed, I want to present the same instance of my TimerViewController each time the button is pressed. I think I have gotten fairly close with this post here, iOS Swift, returning to the same instance of a view controller. So if you could point me to saving the instance of TimerViewController , that would work the best. This is the code I have right now - var yourVariable : UIViewController! if yourVariable == nil { let storyboard =

问题 I have a string containing the name of a generic class with specified type: string s = "GenericRouteHandler<MemberHandler>"; How do I instantiate an instance from this string? I know how to instantiate a concrete class using Type.GetType() and then use Activator but I am not sure where to go with a generic class. 回答1: Like this typeof(GenericRouteHandler<>).MakeGenericType(typeof(MemberHandler)); Of course if you don't have the types you have to use Type.GetType(string) to get the type

问题 I'm looking for a way to get the instance ID of a given object / resource with PHP, the same way var_dump() does: var_dump(curl_init()); // resource #1 of type curl var_dump(curl_init()); // resource #2 of type curl How can I get the instance count without calling var_dump()? Is it possible? 回答1: Convert it to an int to get the resource ID: $resource= curl_init(); var_dump($resource); var_dump(intval($resource)); 回答2: (int) curl_init() 回答3: This is a very interesting question... I would be

问题 The book I'm currently reading has me write the following code : -(IBAction)displaySomeText:(id)sender { NSString *cow = @"Milk"; NSString *chicken = @"Egg"; NSString *goat = @"Butter"; NSArray *food = [NSArray arrayWithObjects:cow, chicken, goat, nil]; NSString *string = @"The shopping list is: "; string = [string stringByAppendingString:[food componentsJoinedByString:@", "]]; [textView insertText:string]; } I understand somewhat how arrays work but I need help understanding the following

问题 I have a new requirement on Array object. So I need to add my own method to built-in Array class. How do I add a new method so that whatever Array object I create, it will also have my instance method? 回答1: Use Ruby Open Classes: class Array def mymethod #implementation end end 回答2: The other answers basically show you can add a method to the class by redefining the class, just to add to that, an example could be like this: class Array def third size > 2 ? self[2] : nil end end a = [1, 2, 3,

问题 There are many questions related to the use of the Singleton pattern in python, and although this question might repeat many of the aspects already discussed, I have not found the answer to the following specific question. Let's assume I have a class MyClass which I want to instantiate only exactly once. In python I can do this as follows in the code myclass.py : class MyClass(object): def foo(self): .... instance = MyClass() Then in any other program I can refer to the instance simply with