this

Save access to this scope

由 爱⌒轻易说出口 提交于 2019-11-26 09:04:40
问题 I have color stored in a data attribute on my button that I wanted to use in a toggle. However, when I tried to access the data information using this , no data was available. How can I keep my access to the correct this scope? I was trying to only toggle the given color for the elements which didn\'t contain Skip. html <div> <input id=\"toggleButton\" type=\"button\" value=\"Toggle\" data-color=\"Red\" /> </div> <div id=\"toggleSet\"> <div>Element</div> <div>Skip</div> <div>Element</div> <

Use of “this” keyword in formal parameters for static methods in C#

由 邮差的信 提交于 2019-11-26 08:42:31
问题 I\'ve come across several instances of C# code like the following: public static int Foo(this MyClass arg) I haven\'t been able to find an explanation of what the this keyword means in this case. Any insights? 回答1: This is an extension method . See here for an explanation. Extension methods allow developers to add new methods to the public contract of an existing CLR type, without having to sub-class it or recompile the original type. Extension Methods help blend the flexibility of "duck

this is undefined inside arrow function

由 旧城冷巷雨未停 提交于 2019-11-26 08:36:05
问题 I am trying to access this inside my arrow function: import myObject from \'../myObjectPath\'; export const myClass = Fluxxor.createStore({ initialize() { this.list = []; this.id = null; }, myOutsideFunction(variable1) { // here this in NOT undefined myObject.getMyList(this.id, (myList) => { // here this in undefined this.list = myList; } }); )}; But inside arrow function which in ma callback function this is undefined!! I am using babel to transpile the code: myOutsideFunction: function

this: Cannot use this in static context

由 早过忘川 提交于 2019-11-26 08:27:24
问题 Can you please help me with below code. The error is: \"Cannot use This in a static context\" public class Sample2 { /** * @param args */ public static void main(String[] args) { Sample2 sam=new Sample2(); //Below code works fine System.out.println(sam); //Below code is displaying error System.out.println(this); } } 回答1: See, "this" keyword refers to current object due to which method is under exceution. As, you cannot call static method using instance of class. That is why, "this" can't be

What object javascript function is bound to (what is its “this”)?

由 别等时光非礼了梦想. 提交于 2019-11-26 07:47:51
问题 I know that inside the function it is this . var func = function { return this.f === arguments.callee; // => true, if bound to some object // => false, if is bound to null, because this.f === undefined } var f = func; // not bound to anything; var obj = {}; obj1.f = func; // bound to obj1 if called as obj1.f(), but not bound if called as func() var bound = f.bind(obj2) // bound to obj2 if called as obj2.f() or as bound() Edited: You can\'t actually call obj2.f() as f doesn\'t become a

What is the &#39;this&#39; pointer?

由 雨燕双飞 提交于 2019-11-26 06:34:35
问题 I\'m fairly new to C++, and I don\'t understand what the this pointer does in the following scenario: void do_something_to_a_foo(Foo *foo_instance); void Foo::DoSomething() { do_something_to_a_foo(this); } I grabbed that from someone else\'s post on here. What does this point to? I\'m confused. The function has no input, so what is this doing? 回答1: this refers to the current object. The keyword this identifies a special type of pointer. Suppose that you create an object named x of class A ,

How can I exclude $(this) from a jQuery selector?

由 让人想犯罪 __ 提交于 2019-11-26 06:14:40
问题 I have something like this: <div class=\"content\"> <a href=\"#\">A</a> </div> <div class=\"content\"> <a href=\"#\">B</a> </div> <div class=\"content\"> <a href=\"#\">C</a> </div> When one of these links is clicked, I want to perform the .hide() function on the links that are not clicked. I understand jQuery has the :not selector, but I can\'t figure out how to use it in this case because it is necessary that I select the links using $(\".content a\") I want to do something like $(\".content

difference and when to use getApplication(), getApplicationContext(), getBaseContext() and someClass.this

由 自作多情 提交于 2019-11-26 05:56:36
I'm new to android and I'm trying to understand the difference between getApplication() , getApplicationContext( ), getBaseContext() , getContext() and someClass.this and especially when to use the these methods in the following code lines: When I launch a toast what is the difference between these and in which cases to I use them? Toast.makeText(LoginActivity.this, "LogIn successful", Toast.LENGTH_SHORT).show(); Toast.makeText(getApplication(), "LogIn successful", Toast.LENGTH_SHORT).show(); Toast.makeText(getApplicationContext(), "LogIn successful", Toast.LENGTH_SHORT).show(); Toast.makeText

Leaking this in constructor warning

由 ぃ、小莉子 提交于 2019-11-26 05:52:25
问题 I\'d like to avoid (most of the) warnings of Netbeans 6.9.1, and I have a problem with the \'Leaking this in constructor\' warning. I understand the problem, calling a method in the constructor and passing \" this \" is dangerous, since \" this \" may not have been fully initialized. It was easy to fix the warning in my singleton classes, because the constructor is private and only called from the same class. Old code (simplified): private Singleton() { ... addWindowFocusListener(this); }

this inside function

由 那年仲夏 提交于 2019-11-26 05:26:26
问题 My question is: function Foo() { this.foo = \"bar\"; // <- What is \"this\" here? } From what I can tell it depends on how Foo is used, i.e. as a constructor or as a function. What can this be in different circumstances? 回答1: The this keyword refers to the object the function belongs to, or the window object if the function belongs to no object. It's used in OOP code, to refer to the class/object the function belongs to For example: function foo() { this.value = 'Hello, world'; this.bar =
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