I have a child sidebar component with some dropdowns. Simplified example:
You select a status here and it re renders the table/dashboard view in the parent component. That is handled via $emit in the child component like so:
selectedStatus: function(status) {
this.$emit('updateStatus', status)
},
No issues there. Now I'd like to be able to clear or reset this input from the parent component. As I said this is a simplified example and there are many dropdowns, a couple datetime selectors, and other inputs to clear.
If I do something like
this.selectedStatus = [] in the parent, it does indeed reset/re render the table/data properly but it still shows the UI piece (ie, the selected status in the dropdown).
If I do something like
this.selectedStatus = [] in the child it does correctly remove/alter the UI piece to where it clears the dropdown.
What is the correct approach here to clear child filters/inputs from the parent?
I recommend you to read this article, it explains all the ways to make a child component rerender (and therefore reset it's state).
Related
I am adding child component dynamically using ComponentFactoryResolver and able to using ngModel in the child component but it's working as a one way data binding rather than two way.
I tried by adding child component tag and it's working but in my case I can't add that. So need a solution with ComponentFactoryResolver. Please check the below stackblitz for better understanding. i need the parent component vlue to be update on second text box value change.
Example Stackblitz.
const factory = this.componentFactoryResolver.resolveComponentFactory(AppChildComponent);
const component = factory.create(this.ViewContainerRef.parentInjector);
component.instance['childData']=this.parentData;
this.ViewContainerRef.insert(component.hostView);
I have a parent component that loads dinamycally childs components via *ngFor. My parent component loads data for rendering child components. There is extra data needed after on user request.
The html of parent component:
<panel *ngFor="let item of collection" (selected)="onTogglePanel($event, item)">
<div panel-body>
<item-detail
*ngIf="item.detail; else templateLoading"
[detail]="item.detail"
(eventItemLoad)="getExtraData($event, item.detail)"
></item-detail>
</div>
</panel>
Each child component, emits an event to the parent component, that will make an http request for getting the data.
The question is, how can I pass the data to the sepecific child component?
I have been reading about invoking child method from parent, but I don´t know really how to invoke only for specified child.
NOTE: Perhaps my approach of parent getting data and passing to children is not correct and each child should get the data. Any advice for the approach is welcome. Thanks for any help.
The child should get the data on its own.
It looks like you just need item.detail to get the additional data. So if you don't need anything from the parent, just let the child make the http request.
This is about separation of concerns : in Angular you achieve this by creating components, each one serving its specific purpose - and not "messing" with another one if it is not needed.
I have two different components in my React application.One component to display pop up, and other for text search field.
There is no relation(parent-child)between them.
My question is when user clicks pop up message(component), be focused text field in another component.
How can I handle this situation without using document.getElementById?
only using a react a specific way like reactDOM with ref.
Is it possible to handle like that?
Thanks
Find the common parent component, and write a function which updates a state with ref of the element to be focused. Pass down that function as props to the second component.
And use <input ref={r => this.props.func(r)
Now on click of first component you can access this parent state.
I am looking for all web but I no found any solution, maybe because I am newer with React-Native universe.
Well, my question is about Node Parent change value of Children.
My situation is, I have a data controller and this data controller listen data from events and when the events happen it need update a component like Slider.
the render need be.
<DataListener url={this.state.service_url}>
<Slider style={this.styles.slider_component}/>
</DataListener>
I need understand the cycle to get a default Slider with my Class DataListener. Is it with props in constructor? How can I get the slider inside DataListener and change this value like this.default_slider.value = 0.4
Thanks Advance
Victor C Tavernari
You should pass down the value as a prop and then your slider component can deal with it appropriately. Of course DataListener has to get the value in the first place and as you have detailed that let's assume it is in state (when you update state (via this.setState(newState)) it will cause a re-render of the DataListener which will in turn re-render the Slider with the new property):
<DataListener url={this.state.service_url}>
<Slider style={this.styles.slider_component} value={this.state.value}/>
</DataListener>
the data controller event you refer to would then be something like
onEvent(e) {
this.setState({value: e.value});
}
I have a child component that renders several list elements from an array. This child component's list items when clicked turns to input boxes, and can be changed. But I need to also put focus on the input box when it's rendered.
Here is a quick view of what my app is so far.
I'm making list items from an array in the state and it's then mapping around while populating the array items in the parent components render function (like any other tutorial shows).
render: function() {
var listItems = this.state.ingredients.map(function(item) {
return <ListItem key={item.id} id={item.id} refer={item.ref} handleChange={this.toggleEnv} env={item.env} ingredient={item.text} />;
}.bind(this));
id for callback from the child component to search the array using id.
env for toggling states from list item to input box and back to list item.
toggleEvn is the function i use for every manipulation of the child component with callback a child component make.
Now that refer property where I pass the item.ref to the child component so it can attach it to the input and then use
componentDidMount: function() {
ReactDom.findDOMNode(ref-name-passed-from-child-component-callback).focus();
}
Where in the child element i pass clicked list items ref (which is equal to input box's ref) to the callback so it can be captured by the parent but it passes null so i can't add the focus from ReactDom.findDOMNode().
I checked in react documentation and they say something like
Never access refs inside of any component's render method – or while any component's render method is even running anywhere in the call stack
I'm a very newbie in react and i think this is referring to my current situation.
But they also have another way of using refs by passing a callback in ref which will be used when some button is clicked as seen here https://facebook.github.io/react/docs/more-about-refs.html
I followed the example by
Adding a ref callback like this ref={(ref) => this.myTextInput = ref}
in my input tag.
Instead of the button, i triggered the function when the list item is clicked. This doesn't work since the this.myTextInput isn't created yet. (Since this function is triggered when list item is clicked and it's before the input is rendered.
At this point i was stuck completely because i can't pass this ref to check it in componentDidMount.
I'm convinced that I'm missing on some understanding here please with refs, child components and callback. Please help.