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shadowfox
Frequent Visitor

Change in PCF Controls load null data on initial load

Recently a control I have had published for quiet some time started to break (in July). This code base has not changed and has been working fine for some time. Trying to determine what update is causing this change in behavior. The issue is on initial load the field mapped to the control shows null data. But if you do a post back again (F5) it will work on the second load and if you exit the record and re-open it will work fine. Trying to understand why all of a sudden it's displaying null on initial load. As I have said - the code hasn't changed since Mar 18, 2020.  This is a modified version of the PeoplePicker control -

 

import { IInputs, IOutputs } from "./generated/ManifestTypes";
import * as React from 'react';
import * as ReactDOM from 'react-dom';
import { PeoplePickerTypes, IPeopleProps, IPeoplePersona } from './Peoplepicker';

export class OfficeUIFabricReactPeoplePicker implements ComponentFramework.StandardControl<IInputs, IOutputs> {
	private theContainer: HTMLDivElement;
	private notifyOutputChanged: () => void;
	private _context: ComponentFramework.Context<IInputs>;
	private props: IPeopleProps = {
		//tableValue: this.numberFacesChanged.bind(this),
		peopleList: this.peopleList.bind(this),
	}

	/**
	 * Empty constructor.
	 */
	constructor() {

	}

	/**
	 * Used to initialize the control instance. Controls can kick off remote server calls and other initialization actions here.
	 * Data-set values are not initialized here, use updateView.
	 * @Param context The entire property bag available to control via Context Object; It contains values as set up by the customizer mapped to property names defined in the manifest, as well as utility functions.
	 * @Param notifyOutputChanged A callback method to alert the framework that the control has new outputs ready to be retrieved asynchronously.
	 * @Param state A piece of data that persists in one session for a single user. Can be set at any point in a controls life cycle by calling 'setControlState' in the Mode interface.
	 * @Param container If a control is marked control-type='standard', it will receive an empty div element within which it can render its content.
	 */
	public init(context: ComponentFramework.Context<IInputs>, notifyOutputChanged: () => void, state: ComponentFramework.Dictionary, container: HTMLDivElement) {
		// Add control initialization code
		this.notifyOutputChanged = notifyOutputChanged;
		this._context = context;
		this.theContainer = container;
	}


	/**
	 * Called when any value in the property bag has changed. This includes field values, data-sets, global values such as container height and width, offline status, control metadata values such as label, visible, etc.
	 * @Param context The entire property bag available to control via Context Object; It contains values as set up by the customizer mapped to names defined in the manifest, as well as utility functions
	 */
	public async updateView(context: ComponentFramework.Context<IInputs>) {
		// Add code to update control view
		this.props.context = context;
		if (context.parameters.peoplePicker.raw !== null) {
			if (context.parameters.peoplePicker.raw!.indexOf("text") > 1) {
				this.props.preselectedpeople = JSON.parse(context.parameters.peoplePicker.raw!);
			}
		}

		ReactDOM.render(
			React.createElement(
				PeoplePickerTypes,
				this.props
			),
			this.theContainer
		);

	}

	/** 
	 * It is called by the framework prior to a control receiving new data. 
	 * @returns an object based on nomenclature defined in manifest, expecting object[s] for property marked as “bound” or “output”
	 */
	public getOutputs(): IOutputs {
		return {
			peoplePicker: JSON.stringify(this.props.people)
		};
	}

	private peopleList(newValue: IPeoplePersona[]) {
		if (this.props.people !== newValue) {
			if (newValue.length === 0) {
				this.props.people = undefined;
			}
			else {
				this.props.people = newValue;
			}

			this.notifyOutputChanged();
		}
	}

	/** 
	 * Called when the control is to be removed from the DOM tree. Controls should use this call for cleanup.
	 * i.e. cancelling any pending remote calls, removing listeners, etc.
	 */
	public destroy(): void {
		// Add code to cleanup control if necessary
		ReactDOM.unmountComponentAtNode(this.theContainer);
	}
}

 

1 ACCEPTED SOLUTION

Accepted Solutions

No, the "null first, value second" thing is something I've seen before, that's why I knew to guess it. I am not sure how to reliably reproduce (or avoid) it, which is why I just take approaches that circumvent it. So again, make sure your nullcheck is safe (you already have a !== null, so that should safely avoid any exceptions) then add in a line right before your reactdom.render, basically the same thing you are doing in Dispose:

 

ReactDOM.unmountComponentAtNode(this.theContainer);

 

This will let your component run once, with a null string, which will render nothing in the picker. But then when updateView gets called again and has a value, it will unload that empty version of the control and reload with an actual value.

View solution in original post

18 REPLIES 18
cchannon
Solution Sage
Solution Sage

Nothing is jumping out at me as problematic in this code. What do you see when you debug the control using browser developer tools?

DianaBirkelbach
Super User
Super User

Hi @shadowfox 

 

 I don't know if that has something to do with it, but what's the reason of searching the "text" inside the peoplePicker parameter?

context.parameters.peoplePicker.raw!.indexOf("text")

 

If after the reload it works, maybe the first render triggers the "peopleList" witch changes the value.


Otherweise, I agree with @cchannon  , it depends on which values are passed to updateView when it's triggered. 

 

Kind regards,

Diana

 

Kind regards,
Diana
----------
Please click "Accept as Solution" if my post answered your question so that others may find it more quickly. If you found this post helpful consider giving it a "Thumbs Up."

@cchannon When using the debug tool - on the initial load when it first hits the updateview this is what I see (image below which shows the field being null) -

shadowfox_0-1628085445069.png

But then on the second call of the updateview is shows the data but at this point it's not rendering.

shadowfox_1-1628085522565.png

If I close the page and re-open the initial load this time has a value - 

shadowfox_2-1628085618220.png

This is the part that makes no sense to me. The fact on a cold load - the initial is null but then after closing and re-opening it's fine. As I said - this has been working wonderfully for over a year with no issues but this behavior just started. I did also try to update my npm packages and see if that fixed it but no luck.

 

Thanks.

 

@DianaBirkelbach thanks for the reply! The indexOf("text") is verifying the JSON has the label text in it to get the label for the control. Otherwise if text is missing, then the JSON main part is malformed and won't work. Hope that helps better explain that. Sadly - with the issue I'm having - I'm not hitting this part since the field is passing null on the initial cold load.

 

Thanks!

Hi @shadowfox , 

 

Now I'm making some wild guessing.
Maybe the "this.props" makes some trouble because the props is reserved in react, and the PCFs are based on react. Thinking of it, you actually don't need the private "props" in your class, which you also pass as a reference to the component PeoplePickerTypes as props. I also suppose that the changing of the content inside the props won't be reflected, since you render the PeoplePickerTypes with the same reference of the props, but you change the content (props should be immutable).

In your class, you only need the value (in your case the people).
So I suggest, not to define a private "props" in your class. The props you pass to your PeoplePickerTypes can be defined just where you call the render function. All you need to keep in the class is the value for people, and the function itself (peopleList).

 

I've also saw that the updateView is declared "async". Not so sure if it's supposed to work that way, but I also don't see where you have the await. I suggest to delete the async.

 

It the explanation is not clear enough, please let me know.

Hope it helps.

 

Kind regards,

Diana

Kind regards,
Diana
----------
Please click "Accept as Solution" if my post answered your question so that others may find it more quickly. If you found this post helpful consider giving it a "Thumbs Up."

@shadowfox When you say, "the field is passing null" do you mean

context.parameters.peoplePicker.raw

is coming through as null even though the attrib does contain a JSON value?

@cchannon Yes - that was on the debugger image I grabbed. The context.parameters.peoplePicker.raw is null on initial cold load. Very crazy - this is something new I'm experiencing. 

@DianaBirkelbach thanks for the reply. You did catch something I was trying just to see if it made a difference but it didn't. Here is the original code for that part. I was initially just using context.parameters.peoplePicker.raw but wanted to see if the this.props.context made any difference (mostly because I'm stuck and nothing else I tried worked so figured I'd try it just to rule it out). As for the async - this was initially developed as part of the PCF Gallery control - People Picker | PCF Gallery. I have modified the React code quiet a bit to handle any entity and fixed an issue with the async promise. But the index.ts page has been left untouched since I pulled it down. What's blogging my head its been working for over a year now just fine. This makes me think something with how controls are being rendered on cold load and binding has been changed. Thanks for the help!

public async updateView(context: ComponentFramework.Context<IInputs>) {
		// Add code to update control view
		this.props.context = context;
		if (context.parameters.peoplePicker.raw !== null) {
			if (context.parameters.peoplePicker.raw!.indexOf("text") > 1) {
				this.props.preselectedpeople = JSON.parse(context.parameters.peoplePicker.raw!);
			}
		}

		ReactDOM.render(
			React.createElement(
				PeoplePickerTypes,
				this.props
			),
			this.theContainer
		);

	}

 

Well, updateView gets called multiple times onLoad (at least two, could be more depending on what's happening on your form) and you can even force it to fire with Client Script by using the fireOnChange() function.

 

So try debugging again and just put your breakpoint at the top of updateView. Is contex.parameters.peoplePicker null every time updateView gets called, or maybe just the first time?

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