extend

问题 In Javascript, with the following illustration code: class Base { constructor() { this._val = 1 } get val() { return this._val } } class Xtnd extends Base { set val(v) { this._val = v } } let x = new Xtnd(); x.val = 5; console.log(x.val); // prints 'undefined' the instance x will not inherit get val()... from Base class. As it is, Javascript treat the absence of a getter, in the presence of the setter, as undefined. I have a situation in which I have many classes that all have the exact same

问题 I have 2 classes (2 files) db.class.php user.class.php I want to use some functions from db.class.php : db.class.php Class DBManager { /** all functions goes here ...*/ } $DB = new DBManager(); The content of user.class.php is: Class User extends DBManager { function User() { } function Total($table) { $query = $DB->Execute("SELECT * FROM $table"); $total = $DB->NumRows($query); return $total; } } $User = new User(); When I want to use my new function total($table) I get 2 errors: Undefined

问题 Though there is a similar question found here it does not provide an answer, at least not for the general problem. My problem is: Since CoreLocation geocoding is rate limited and the (web-)service I am developing an app for provides its own fallback geocoding service, I want to use this custom geocoding service in case I reach Apple's rate limit. Furthermore, I feel it makes total sense to avoid a custom data type for results returned by this custom REST API and therefore would like to use

问题 Though there is a similar question found here it does not provide an answer, at least not for the general problem. My problem is: Since CoreLocation geocoding is rate limited and the (web-)service I am developing an app for provides its own fallback geocoding service, I want to use this custom geocoding service in case I reach Apple's rate limit. Furthermore, I feel it makes total sense to avoid a custom data type for results returned by this custom REST API and therefore would like to use

问题 How can I add actions to the admin interface of a third party app? Example: I want to have a custom action for the model django.contrib.admin.Group . With "action" I mean the batch action of the admin list view of a model. Related docs: https://docs.djangoproject.com/en/1.7/ref/contrib/admin/actions/ 回答1: Unregister the original model admin for Group model and then register it with your own ModelAdmin : from django.contrib.auth.admin import GroupAdmin from django.contrib.auth.models import

问题 Okay, so this is somewhat related to my previous question on the ColorMatrixColorFilter, but I feel it's a significantly different question. I'm wondering if there's a way - or rather, how to extend the ColorFilter class to create my own custom color filter. For what I'm needing to accomplish, I need to write a custom filter that will query each pixel, convert its RGB value to HSL or LAB, modify the hue, convert it back to RGB, and set that pixel to the new value. I'm thinking I could simply

问题 EDIT Answered: Although my original question didn't explain my needs in exactly the way the answer provided by Konrad Rudolph addressed them, He (by accident or design) essentially wrote for me what I was trying to write! The class itself does not get extended, but has it's functionality extended by making the class aware of new functions which allow it (the class) to handle a wider array of issues. My grateful thanks for an excellent answer which in turn is also a great tutorial, even if it

问题 I have a couple classes that have nearly identical code. Only a string or two is different between them. What I would like to do is to make them "x" from another class that defines those functions and then uses constants or something else to define those strings that are different. I'm not sure if "x" is inheritance or extending or what. That is what I need help with. For example: objectA.m: -(void)helloWorld { NSLog("Hello %@",child.name); } objectBob.m: #define name @"Bob" objectJoe.m

问题 How to extend the session timeout? I tried entering: Session.Timeout = 720; In formLoad and also tried in webconfig : <system.web> <sessionState mode="InProc" cookieless="true" timeout="720" /> </system.web> But still it times out after 10 minutes. Can anyone help about this issue? 回答1: Take a look at this Microsoft Technet article. Check if it suits your needs. <configuration> <system.web> <sessionState cookieless="true" timeout="20"> </sessionState> </system.web> </configuration> 回答2: You

问题 if you have a list of values: values=['130','90','150','123','133','120','160', '45','67', '55','34','130','120','180','130','10'] and wanted to scan through with a window size of 6 and if 4 out of the 6 were >= 100 then keep scanning until there were 3 in a row that were < 100 and then not include those in the list so for example with an empty list called results: results=[] i would like to append those values that satisfied the criteria into the empty list to get results=[('130','90','150',