---
Added: v2.0.0
---
# Form Extensibility and Customisation
_Note: it is assumed you are familiar with Alfresco Process Services (powered by Activiti) form definition structure._
- How components and widgets are rendered on a Form
- Replacing default form widgets with custom components
- Replacing custom stencils with custom components
## How components and widgets are rendered on a Form
All form field editors (aka widgets) on a Form are rendered by means of `FormFieldComponent`
that takes an instance of a `FormFieldModel`:
```html
```
This component depends on `FormRenderingService` service to map `FormFieldModel` to UI component
based on field type or metadata information.
### Component type resolvers
`FormRenderingService` maps field types to corresponding instances exposing `ComponentTypeResolver` interface:
```ts
export interface ComponentTypeResolver {
(field: FormFieldModel): Type<{}>;
}
```
Typically a `ComponentTypeResolver` is a function that takes `FormFieldModel` and returns corresponding component type.
It can be either a predefined component type or a dynamically evaluated based on field properties and metadata.
#### Static component mapping
You can (re)map fields like in the following:
```ts
let customResolver: ComponentTypeResolver = () => CustomWidgetComponent;
formRenderingService.setComponentTypeResolver('text', customResolver, true);
```
or simply:
```ts
formRenderingService.setComponentTypeResolver('text', () => CustomWidgetComponent, true);
```
#### Dynamic component mapping
Alternatively your resolver may return different component types based on `FormFieldModel` state and condition:
```ts
let customResolver: ComponentTypeResolver = (field: FormFieldModel): Type<{}> => {
if (field) {
let params = field.params;
}
return UnknownWidgetComponent;
};
formRenderingService.setComponentTypeResolver('text', customResolver, true);
```
### Default component mappings
| Stencil Name | Field Type | Component Type |
| ------------ | ---------- | -------------- |
| Text | text | TextWidgetComponent |
| Number | integer | NumberWidgetComponent |
| Multi-line text | multi-line-text | MultilineTextWidgetComponentComponent |
| Checkbox | boolean | CheckboxWidgetComponent |
| Dropdown | dropdown | DropdownWidgetComponent |
| Date | date | DateWidgetComponent |
| Amount | amount | AmountWidgetComponent |
| Radio buttons | radio-buttons | RadioButtonsWidgetComponent |
| Hyperlink | hyperlink | HyperlinkWidgetComponent |
| Display value | readonly | DisplayValueWidgetComponent |
| Display text | readonly-text | DisplayTextWidgetComponentComponent |
| Typeahead | typeahead | TypeaheadWidgetComponent |
| People | people | PeopleWidgetComponent |
| Group of people | functional-group | FunctionalGroupWidgetComponent |
| Dynamic table | dynamic-table | DynamicTableWidgetComponent |
| N/A | container | ContainerWidgetComponent (layout component) |
| Header | group | ContainerWidgetComponent |
| Attach | upload | AttachWidgetComponent or UploadWidgetComponent (based on metadata) |
| N/A | N/A | UnknownWidgetComponent |
## Replacing default form widgets with custom components
This is a short walkthrough on replacing a standard `Text` widget with a custom component for all APS forms
rendered within `` component.
First let's create a simple APS form with `Text` widgets:
Every custom widget must inherit `WidgetComponent` class in order to function properly:
```ts
import { Component } from '@angular/core';
import { WidgetComponent } from '@alfresco/adf-core';
@Component({
selector: 'custom-editor',
template: `
Look, I'm a custom editor!
`
})
export class CustomEditorComponent extends WidgetComponent {}
```
Now you will need to add it to the application module or any custom module that is imported into the application one:
```ts
import { NgModule } from '@angular/core';
import { CustomEditorComponent } from './custom-editor.component';
@NgModule({
declarations: [ CustomEditorComponent ],
exports: [ CustomEditorComponent ],
entryComponents: [ CustomEditorComponent ]
})
export class CustomEditorsModule {}
```
Every custom widget should be added into all three module collections: `declarations`, `exports` and `entryComponents`.
If you decided to store custom widgets in a separate dedicated module (and optionally as separate redistributable library)
don't forget to import it into your main application one:
```ts
@NgModule({
imports: [
// ...
CustomEditorsModule
// ...
],
providers: [],
bootstrap: [ AppComponent ]
})
export class AppModule {}
```
Now you can import `FormRenderingService` in any of your Views and override default mapping similar to the following:
```ts
import { Component } from '@angular/core';
import { CustomEditorComponent } from './custom-editor.component';
@Component({...})
export class MyView {
constructor(formRenderingService: FormRenderingService) {
formRenderingService.setComponentTypeResolver('text', () => CustomEditorComponent, true);
}
}
```
At runtime it should look similar to the following:
## Replacing custom stencils with custom components
This is a short walkthrough on rendering custom APS stencils by means of custom Angular components.
### Creating custom stencil
First let's create a basic stencil and call it `Custom Stencil 01`:
_Note the `internal identifier` value as it will become a `field type` value when corresponding form is rendered._
Next put some simple html layout for `Form runtime template` and `Form editor template` fields:
```html
Custom activiti stencil
```
Now you are ready to design a test form based on your custom stencil:
Once wired with a new task it should look like the following within APS web application:
### Creating custom widget
If you load previously created task into ADF `` component you will see something like the following:
Let's create an Angular component to render missing content:
```ts
import { Component } from '@angular/core';
import { WidgetComponent } from '@alfresco/adf-core';
@Component({
selector: 'custom-stencil-01',
template: `ADF version of custom Activiti stencil
`
})
export class CustomStencil01 extends WidgetComponent {}
```
Put it inside custom module:
```ts
import { NgModule } from '@angular/core';
import { CustomStencil01 } from './custom-stencil-01.component';
@NgModule({
declarations: [ CustomStencil01 ],
exports: [ CustomStencil01 ],
entryComponents: [ CustomStencil01 ]
})
export class CustomEditorsModule {}
```
And import into your Application Module
```ts
@NgModule({
imports: [
// ...
CustomEditorsModule
// ...
],
providers: [],
bootstrap: [ AppComponent ]
})
export class AppModule {}
```
Now you can import `FormRenderingService` in any of your Views and provide new mapping:
```ts
import { Component } from '@angular/core';
import { CustomStencil01 } from './custom-stencil-01.component';
@Component({...})
export class MyView {
constructor(formRenderingService: FormRenderingService) {
formRenderingService.setComponentTypeResolver('custom_stencil_01', () => CustomStencil01, true);
}
}
```
At runtime you should now see your custom Angular component rendered in place of the stencils:
## See Also
- [Form field model](core/form-field.model.md)
- [Form rendering service](core/form-rendering.service.md)
- [Form component](core/form.component.md)
- [Widget component](insights/widget.component.md)