Angular2: Use Pipe to render templates dynamically

问题

I am creating a form where I get the fields from the backend. After mapping, I have something like this:

genericFilters: {
        iboId: {
            'display': false,
            'template': ''
        },
        iboCode: {
            'display': true,
            'template': 'text_input_iboCode',
            /*'template': 'text/iboCode'*/
        },
        iboName: {
            'display': true,
            'template': 'text_input_iboName'
        },
        iboSurname: {
            'display': true,
            'template': 'text_input_iboSurname'
        },
        iboRank: {
            'display': false,
            'template': 'multiselect_iboRank',
            /*'template': 'select/multi_iboRank',*/
        },
        iboEmail: {
            'display': false,
            'template': 'text_input_iboEmail'
        },
        iboNewsletter: {
            'display': true,
            'template': 'simple_select_iboNewsletter',
            /*'template': 'select/simple_iboNewsletter',*/
        },
    };

My idea behind this is to create each field type (checkbox, multiselect, text, radio, etc.) for the form field at an app level. And use the mapped JSON above to apply a certain field type to every receieved field from the back end.

In my example, the field iboId should have the field type <text_input_iboCode>.

So, in my view, I don't want to have something like this:

<text_input_iboCode></text_input_iboCode>
<text_input_iboName></text_input_iboName>
<text_input_iboSurname></text_input_iboSurname>

I would actually like to have the form creation more abstract, something like this:

<div *ngFor="let field of genericFilters | dynamicTemplateProcessorPipe">
    {{field.template}} <!--This should equal '<text_input_iboName>' for example-->
</div>

Questions:

Am I asking for the moon? Is this even possible? Are there other or better approaches to achieve this? Am I abusing the @Pipe functionality?

I am actually using @Pipe for translations, formatting, looping through objects in templates, etc. I guessed I could also use them to return a <fieldTemplate>.

I will start a research to see if the usage of <ng-template #fieldTemplate> could also be a viable option, in the meanwhile I hope someone could lay some light on the doability of this functionality with @Pipe.

回答1:

After continuing my research I could not find out a way of implementing what I want with @Pipe, and for a good reason: @Pipe is not meant to work like that.

I found instead Angular 4's NgComponentOutlet.

I am starting to work with it, but my first example would be something like this:

@Component({selector: 'text-input-ibo-name', template: '<input type="text" name="ibo_name">'})
class TextIboName {
}
@Component({
  selector: 'ng-my-form',
  template: `<ng-container *ngComponentOutlet="TextIboName"></ng-container>`
})
class NgMyForm {
  // This field is necessary to expose HelloWorld to the template.
  TextIboName = TextIboName;
}

This is the basis. Now I just need to see how to apply <ng-container *ngComponentOutlet="TextIboName"></ng-container> in my *ngFor (see OP).

If people request it, I can update this answer with more concrete and 'final' code.

Update:

This would be my first approach to select the template for that field that is declared on the mapped JSON.

<div *ngFor="let field of genericFilters | dynamicTemplateProcessorPipe">
    <ng-container *ngComponentOutlet="{{field.template}}"></ng-container>
</div>

The classes TextIboName, TextIboCode, TextIboSurname, etc. Will be declared in a common folder and imported to the current component, just to have a more abstract approach.

The goal is to be able to reuse these fields throughout all the App. Like this, I will be able to replicate the field TextIboName in other places without having to Copy/Paste HTML code or templates.

Update 2:

If we move our 'field component', in my example would be TextIboName to an external folder within another @ngModule or we simply want to use an external class from another @ngModule we will have to use NgModuleFactory.

Adapted above code:

@Component({
  selector: 'ng-my-form',
  template: `
    <ng-container *ngComponentOutlet="TextIboName;
                                      ngModuleFactory: myModule;"></ng-container>`
})
class NgMyForm {
  // This field is necessary to expose OtherModuleComponent to the template.
  TextIboName = TextIboName;
  myModule: NgModuleFactory<any>;
  constructor(compiler: Compiler) { this.myModule = compiler.compileModuleSync(OtherModule); }
}

来源：https://stackoverflow.com/questions/43143956/angular2-use-pipe-to-render-templates-dynamically