class

问题 How would I create an NSPredicate to filter by entity of class Contact ? The solution to NSPredicate check for kind of object class crashes: [NSPredicate predicateWithFormat:@"person.class == %@", [Contact class]]; *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'keypath person.class not found in entity <NSSQLEntity User id=12>' Background I have the Core Data entities User (app user) & Contact (address book contact), both children of Person (abstract

问题 This seems like a simple problem but nothing nothing is fixing it. I'm trying to dynamically change the background-color (from white or pink to green) on some text with javascript/jQuery but for some reason it's not working. The text is styled with a CSS class called ".novice". Here's the CSS. It's simple. I've also tried removing background-color completely so it does not already have a set background-color. <style type="text/css"> .novice { background-color: pink; } </style> Here is an

问题 I am trying to write a generic method for deserializing json into my model. My problem is that I don't know how to get Class from the generic type T. My code looks something like this (and doesn't compile this way) public class JsonHelper { public <T> T Deserialize(String json) { Gson gson = new Gson(); return gson.fromJson(json, Class<T>); } } I tried something else, to get the type, but it throws an error I had the class as JsonHelper<T> and then tried this Class<T> persistentClass = (Class

问题 What are ways to get around the problem of only being allowed to extend at most one other class. class Bar { doBarThings() { //... } } class Bazz { doBazzThings() { //... } } class Foo extends Bar, Bazz { doBarThings() { super.doBarThings(); //... } } This is currently not possible, TypeScript will give an error. One can overcome this problem in other languages by using interfaces but solving the problem with those is not possible in TypeScript. Suggestions are welcome! 回答1: This is possible

问题 I have a class inside my DLL. And this DLL provides an "interface" to create objects of this class and call their methods. Class code (simplified): TLogger = class private // public function AddToLog(sBuf: PWideChar): Word; constructor Create(Name: PWideChar); destructor Destroy; override; end; constructor Create(Name: PWideChar); begin // end; destructor TLogger.Destroy; begin // end; function TLogger.AddToLog(sBuf: PWideChar): Word; var Temp1 : WideString; Temp2 : AnsiString; begin Result :

问题 I have a class inside my DLL. And this DLL provides an "interface" to create objects of this class and call their methods. Class code (simplified): TLogger = class private // public function AddToLog(sBuf: PWideChar): Word; constructor Create(Name: PWideChar); destructor Destroy; override; end; constructor Create(Name: PWideChar); begin // end; destructor TLogger.Destroy; begin // end; function TLogger.AddToLog(sBuf: PWideChar): Word; var Temp1 : WideString; Temp2 : AnsiString; begin Result :

问题 Is there a way to list all Variables of a class in Swift? For example: class foo { var a:Int? = 1 var b:String? = "John" } I want to list it like this: [a:1, b:"John"] 回答1: The following should use reflection to generate the list of members and values. See fiddle at http://swiftstub.com/836291913/ class foo { var a:Int? = 1 var b:String? = "John" } let obj = foo() let reflected = reflect(obj) var members = [String: String]() for index in 0..<reflected.count { members[reflected[index].0] =

问题 Is there a way to list all Variables of a class in Swift? For example: class foo { var a:Int? = 1 var b:String? = "John" } I want to list it like this: [a:1, b:"John"] 回答1: The following should use reflection to generate the list of members and values. See fiddle at http://swiftstub.com/836291913/ class foo { var a:Int? = 1 var b:String? = "John" } let obj = foo() let reflected = reflect(obj) var members = [String: String]() for index in 0..<reflected.count { members[reflected[index].0] =

问题 i am trying to compile this very simple piece of code class myList { public: std::vector<std::string> vec; class Items { public: void Add(std::string str) { myList::vec.push_back(str); }; }items; }; int main() { myList newList; newList.items.Add("A"); } what can i do to make this work without creating more objects that needed or overcomplicating stuff... 回答1: Add a couple of constructors and a pointer to the parent class. #include <string> #include <vector> class myList { public: std::vector

问题 I have the following Class code and when Debug it kept showing the following error: 1.) Unhandled Exception: java.lang.ClassNotfoundException 2.) Unhandled Exception:java.lang.NoSuchMethodException Error Log: /apps/robotapp/Utils.java:32: error: exception IOException is never thrown in body of corresponding try statement } catch (IOException e) { ^ /apps/robotapp/Utils.java:24: error: unreported exception ClassNotFoundException; must be caught or declared to be thrown final int tckName =