computed-properties

问题 I am using Database First approach and I have created model from a database. Now I have a datagrid view in my Winforms app, that is bound to a binding source. And all that works fine (an appropriate data is shown in datagrid view). Now the problem is, how to add a computed property that consists of two values (already found in db) ? For an example: Lets say that I have a table user (id, username, first_name, last_name, user_type) but I want to have different columns in my bound datagrid view

问题 I'm using Angular 8 and am trying to do something that seems like it should be really simple. I'm retrieving an array of records from my controller on the server using http.get. Those records have a particular type (defined within Angular) and I would like to add a computed property to that type called "meetsTarget". My problem is that it is not recognising that that property exists on the results I get back from the server. Question 2: Becasue that property is computed from other properties,

问题 im learning vue js following a channel on YT, the video was sent last year, so i think its not working due to some changes on VueJS itself, but it would be great if you guys could help me with this codeio link: http://codepen.io/myrgato/pen/BWWxdQ HTML <script src="https://unpkg.com/vue@2.2.2"></script> <div id="app"> <button @click="increment">Increment</button> <p>Counter: {{counter}}</p> <p>Clicks: {{clicks}}</p> </div> JS new Vue({ el: '#app', data: { counter: 0, clicks: 0 }, methods: {

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 2 years ago . I'm an experienced Ember.js developer. In guides, we can find an example of Computed Property with full name (synchronous, easy, relies on first name and last name). In the wild, we can find however lots of usages of Computed Properties in an asynchronous manner (for example

问题 I have two models, folder and files. A folder has many files. If I say folder.get('files') I get all the files associated with that folder ordered by id. I would like the array of files to be order by something other then the id; lets say createDate. If possible, I do not want to make a computed property that has a different name then files . Any help would greatly be appreciated? 回答1: As mentioned in my comment you need to create an computed property files in your controller, which contains

问题 I have a simple belongsTo model relationship: contract.js: export default DS.Model.extend({ object : DS.belongsTo('object'), .... }) object.js: export default DS.Model.extend({ street : DS.attr('string'), zip : DS.attr('string'), city : DS.attr('string'), ... }) In my controller for an entity that holds many contracts , I'd like to sort by the street name of the associated object , but somehow this export default Ember.Controller.extend({ sortOrder: ['object.street'], sortedObjects: Ember

问题 I'm just learning Ember and I'm a bit confused about computed properties. Everything in the guides uses strings, like a computed property that creates a full name out of a first and last name, etc. Anyway, I'm confused about how to use integers because it seems like the syntax almost demands the use of strings. As an example, I have a property on my controller called count . import Ember from 'ember'; export default Ember.Controller.extend({ count: 0, counter: Ember.computed('count', function

问题 I'm not new to Vue.js, but I'm going through the docs again, trying to pick up on anything I missed the first time. I came across this statement in basic example section of using computed properties: You can data-bind to computed properties in templates just like a normal property. Vue is aware that vm.reversedMessage depends on vm.message , so it will update any bindings that depend on vm.reversedMessage when vm.message changes. And the best part is that we’ve created this dependency

问题 If I have a custom element Polymer({ name: 'dane', computed: { message: 'greet(name)' }, greet: function(name) { return 'hello ' + name + Date.now(); } }) When I change name polymer will automatically recompute message , but is there a way to recompute message without changing name ? 回答1: You could add another input value to the compute expression, i.e.: message: 'greet(name,x)' and then force a re-compute by updating x. Keep in mind computed properties are read-only so you can't directly

问题 I got a printerList computed property that should be re-evaluated after getPrinters() resolve, but it look like it's not. sources are online: optbox.component.vue, vuex, optboxes.service.js Component <template> <div v-for="printer in printersList"> <printer :printer="printer" :optbox="optbox"></printer> </div> </template> <script> … created() { this.getPrinters(this.optbox.id); }, computed: { printersList() { var index = optboxesService.getIndex(this.optboxesList, this.optbox.id); return this