pcf assign output params for canvas app operations

[cchannon]

I am building a dataset type pcf specifically to embed in a powerapp. This control needs to perform limited API operations ("PUT") but since we don't have a webapi in pcf for canvas, that makes this part a bit tricky.

I want to be lazy about my coding and pass the operations back up to the containing powerapp so I can handle them there--where I don't need to handle my own authentication.

Is there a way to assign value to params of type "output" such that they can be picked up by a canvas app for OnChange events, or is my only real option here to import adal and use app authentication from inside pcf?

[cchannon · Accepted solution]

OK, I think I have it myself, at least partially...

part 1: define the output param in ControlManifest.Input.xml:
<property name="output" display-name-key="outputVal" description-key="Output from the conrol" of-type="SingleLine.Text" usage="output"/>

part 2: define the datatype of the output in manifesttypes.d.ts:
export interface IOutputs { output?: string; }

part 3: attach your own notifyoutputchanged event to the init param:
public init(context: ComponentFramework.Context<IInputs>, notifyOutputChanged: () => void, state: ComponentFramework.Dictionary, container:HTMLDivElement)
{
this._notifyOutputChanged = notifyOutputChanged;
}

part 4: designate a return val for the type defined in manifesttypes:
public getOutputs(): IOutputs { return {output : "test"}; }

part 5: call your notifyoutputchanged event wherever in code you want the change recognized:
this._notifyOutputChanged();

part 6: in PowerApps, add your pcf control, then add a label valued as <controlname>.output

... All that still missed the onchange part, but I am sure I will figure that out eventually.

[alrez]

Hi,

Thanks for your follow up. I am glad you were able to get this issue figured out. Thanks for the information, hopefully it can help future communities members with their issues in the future. 

Regards,

Alex

-------

Community Support Team _ Alex Rezac
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[Anonymous]

Hi, @cchannon 

I have been looking for something like this. Thanks for the share. 
Do you mind sharing your code (as a zip file, maybe) so that I may compare it with mine to see where I am going wrong. 

Thanks.

[cchannon]

Wow. This is an old one. I don't still have the code for this, but the process is pretty simple: 

• You update your manifest to declare the Output parameter
• You rebuild your node project
• You call notifyOutputChanged whenever you have a change to your value
• You provide the updated value in getOutputs
• You handle the outputs in your canvas app as <controlname>.output

If you're hitting issues in there, is there a specific error message you're seeing?

[Anonymous]

Let me try and provide some context.
I have a separate javascript code that reads data from a serial port. I managed to convert the code to typescript. I am trying to include that very code (either one of two) into the index.ts file.
I hope my explanation wasn't ambiguous. 

[Anonymous]

Would it help if I attached the serial port code here? 

[cchannon]

I've never tried to read from a serial port with a pcf, not even sure it is possible. In any event it is a totally separate topic from this one. I suggest you spin up a new thread to see if anyone else has tried it.

But for the record, I'd first make sure you've enabled all uses-feature elements for Device:

If all of them are enabled and you still can't read from the serial port, it might just not be a supported capability.