javascript - vue parent-child component passes data

The parent component passes an array to the child component. This data needs to be called in the child component. How to pass it? 1. The child component uses props to receive the data of the parent component and cannot be used in js. 2. Use the wacth method to monitor and not execute it at all. Plea...

高洛峰 2017-06-26 10:57:44 0  4  1043

How does a PHP static method call a non-static method of the parent class?

1. this calls the parent class method: 2. self calls the parent class method: 3. parent calls the parent class method: Is there no way for a subclass static method to call a parent class non-static method?

淡淡烟草味 2017-06-08 11:01:40 0  5  1120

java - When a member variable with the same name is called polymorphically, why is the member variable of the parent class accessed?

At first I guessed that since the member variables of the parent class and the subclass are each stored in the heap, it may be due to the existence of the parent class, so the member variables of the parent class are found first. Then I tested it, the code is as follows: {code...} The output is: Z:t...

女神的闺蜜爱上我 2017-06-12 09:27:03 0  2  997

javascript - Issues about coordinate calculation after trasform

After I made a function of dragging pictures in the parent container, I used transform to change the parent container, rotate it, stretch it, etc. After that, the calculation of coordinates started to get messy. I would like to ask if I want it to be What should I do if it works normally? The draggi...

巴扎黑 2017-07-01 09:12:23 0  1  1533

javascript - JS inheritance, how to avoid the situation where the object type attribute of the parent class prototype will be affected by the subclass;

Parent is the parent class, and child inherits parent. When the sex value of the child instance is modified, it will cause the sex of the parent and other subclass instances to change; whether this type of object type attributes can only be placed in the constructor, or whether it is agreed upon All...

过去多啦不再A梦 2017-06-30 09:59:00 0  4  937

Is there a parent selector in CSS?

How to select the <li> element that is the direct parent of the anchor element? For example, my CSS might look like this: li<a.active{property:value;} Obviously, it is possible to achieve this using JavaScript, but I was hoping for a CSSLevel2-native workaround. The menu I'm try...

P粉270842688 2023-08-21 10:49:24 0  2  509

Is there a CSS parent selector?

How to select an element that is the direct parent of an anchor element? For example, my CSS should look like this: li<a.active{property:value;} Obviously there are ways to achieve this using JavaScript, but I'm hoping there's some kind of workaround for CSSLevel2 itself. The menu I'm trying ...

P粉176980522 2023-08-23 10:53:50 0  2  530

MySQL trigger not working after delete update

Sorry to ask this question again as there is a lot on the forum about this issue. But I hope my problem is different from others. Sorry for my bad English. First I have 2 tables (parent and child) parent (location) loc_idloc_size1100275 child (region) ar_idar_loc_idar_size12352240 this is my post de...

P粉155832941 2024-02-03 22:07:06 0  1  393

Can't use constants with empty()?

parent::_initialize();// Inherit the initialization operation in the parent class. It is different from what the teacher said. In addition, if(empty(USER_ID)) reports an error, if(USER_ID!=null) can.

刘磊 2018-11-01 16:04:04 0  2  1426

javascript - If the parent nodes of the nodes to be operated on by appendchild and removechild are both body, then there is no need to obtain the body parent node in advance. or

If the parent nodes of appendchild and removechild are both body, there is no need to obtain the body parent node in advance. Or if the parent node is not the body, it is necessary to obtain the parent node in advance before using it?

为情所困 2017-06-14 10:51:27 0  5  1037

JS: How to build an object based on parent properties

I'm trying to create a JS object containing all URLs. I want to achieve this through the data() part: exportdefaultdefineComponent({name:'MyPage',data(){backendUrls:{...}}}) In a simpler way it would look like this: backendUrls :{baseUrl:"http://localhost:8080",baseUrlWithPrefi

P粉883223328 2024-04-04 21:08:50 0  1  1612

Only the next level can be found based on the id passed from the front end.

'pid'=>$id can only be found at the next level, but it should not be found at the next level, because the $id passed is fixed, and the grandson cannot be deleted based on the parent.

浮尘 2022-08-15 23:54:11 0  2  1181

The child window operates the parent window, but the output does not respond.

The first two sentences are executable, but the last sentence cannot be implemented.

P粉722478067 2024-04-19 15:37:47 0  1  2224

php - How does Laravel's Baum obtain the final parent class id of a certain record?

For example, I want to get the final parent class of the little black pig with ID 10. In the table, the parent_id is 9, but what I want to get is 5. Is there any way? Or I want to judge whether a certain record belongs to The final parent class

某草草 2017-06-06 09:54:07 0  3  737

Recursive call - javascript recursive array recursion problem

Now there is a need to assemble a tree node based on the data requested by the server, that is, the parent-child node. The data structure after the server request is as shown below. Topology is an object, and the key under the object is a parent and value. is the child array. For example, 1 in the p...

阿神 2017-06-26 10:50:17 0  3  978

javascript - Confusion about class and super in ES6

{Code...} After reading Ruan Yifeng's ES6 tutorial, I am still a little confused about class and super. First, create a Book class and then create a subclass Book to inherit the parent class Book. Super calls the constructor of the parent class and calls it in toSay. The getName() method of the pare...

黄舟 2017-05-19 10:31:04 0  2  788

javascript - insertbefore issue with replacing parent element

Code before modification {code...} Code after modification {code...} After modification, elements cannot be added. What is the problem. The previous addition had body as the parent element and was used directly without passing it. I have nested a div and fetched the elements in advance. But still ca...

欧阳克 2017-06-14 10:52:13 0  2  924

javascript - How to select the node corresponding to the attribute structure and obtain the corresponding id and parent id

The information returned by the tree structure is as follows. When selected, "state": {"selected" : true} will be generated accordingly. Now I want to get the corresponding id when selected and the id of the parent. How to solve it elegantly? ? {Code...} is similar to Demo http:/...

淡淡烟草味 2017-05-19 10:29:19 0  1  533

javascript - Is it a prototype problem again?

I don’t understand what is the essential difference between the following two ways of writing? {Code...} The above way of writing is to use the prototype to allow the instantiated object to call the function of the parent class. The following method does not pass the prototype, but it is exactly the...

怪我咯 2017-05-19 10:30:56 0  3  574

c++ - A question about static_cast

The static_cast operator converts expression to type-id type, but there is no runtime type checking to ensure the safety of the conversion. ① Used for conversion of pointers or references between base classes (parent classes) and derived classes (subclasses) in the class hierarchy. Perform upcasting...

阿神 2017-06-05 11:11:51 0  1  885