使用服务动态加载 NgModule entryComponents [英] Load NgModule entryComponents dynamically using service

问题描述

您好，我是 angular2 和 typescript 的新手.我正在动态加载组件，我想知道是否有一种方法可以使用模块的声明"和入口组件"中的服务来声明我的组件.

Hi I am new to angular2 and typescript. I am loading components dynamically and I was wondering if there is a way to declare my components using a service in the module's "declarations" and "entryComponents".

使用打字稿，我可以通过执行以下操作来实现它:

Using typescript, I am able to achieve it by doing the following:

import { ComponentLoaderService } from './../../services/component-loader.service';

let componentsToLoad = ComponentLoaderService.getComponents();

@NgModule({
  declarations: [ componentsToLoad ],
  entryComponents: [ componentsToLoad ],
})
export class testModule {}

这确实有效，但前提是我已经编译并且服务器首先运行.

This actually works, but only if I have compiled and the server is running first.

如果我尝试重新编译并运行它，我会得到这个持续错误:

If, I try to recompile and run it, I get this constant error:

静态解析符号值时出错.不支持函数调用.考虑用对导出函数的引用替换函数或 lambda，"

"Error encountered resolving symbol values statically. Function calls are not supported. Consider replacing the function or lambda with a reference to an exported function,"

我的另一个想法是，有没有办法将组件的加载放在export class testModule {}"部分以填充数组，然后将其传递给 NgModule?

My other thought was, is there a way to put the loading of the components in the "export class testModule {}" portion to fill the array and then pass it to NgModule?

从我目前的测试来看，它不起作用，但我还是新手，所以我可能会遗漏一些东西.

From my current test it doesn't work, but I am still new to this so I might be missing something.

希望有人可以提供帮助.谢谢！

Hope someone can help. Thanks!

这是产生编译错误的代码:

Here is the code that creates the compile error:

我刚刚做了一个新的测试应用程序.

I just did ng new test-app.

然后我在 test-app 文件夹中安装了 npm.

Then in the test-app folder i did npm install.

我创建了/src/app/services/components-loader.service.ts.

I created /src/app/services/components-loader.service.ts.

import { Injectable } from '@angular/core';
import { ViewContainerRef, ViewChild, ComponentFactoryResolver } from '@angular/core';

@Injectable()
export class ComponentLoaderService {
    constructor(private componentFactoryResolver: ComponentFactoryResolver){}

    static getComponents(components: any[]): any[] {
        var tmp = Array();

        for (var i = 0; i < components.length; ++i){
            if (components[i].key == 0){
                tmp.push(components[i].component);
            }
        }

        return tmp;
    }

    load(container: ViewContainerRef, components: any[]): void {
        // clear 
        container.clear();

        for (var i = 0; i < components.length; ++i){
            if (components[i].key == 0 || components[i].key == 'site'){
                const childComponent = this.componentFactoryResolver.resolveComponentFactory( components[i].component );

                // at this point we want the "child" component to be rendered into the app.component:
                container.createComponent(childComponent);          
            }            
        }
    }
}

我创建了一个文件/src/app/components.ts.

I created a file /src/app/components.ts.

import { TestComponent } from './test.component';

export const mainComponents = [
    { key: 0, component: TestComponent },        
];

我创建了一个文件/src/app/test.component.ts.

I created a file /src/app/test.component.ts.

import { Component } from '@angular/core';

@Component({
  template: `test`,
})
export class TestComponent {}

我将/src/app/app.module.ts 修改为如下所示.

I modified /src/app/app.module.ts to look like this.

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { HttpModule } from '@angular/http';

import { AppComponent } from './app.component';
import { mainComponents } from './components';
import { ComponentLoaderService } from './services/components-loader.service';

let componentsToLoad = ComponentLoaderService.getComponents(mainComponents);

@NgModule({
  declarations: [
    AppComponent,
    componentsToLoad
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule
  ],
  providers: [],
  bootstrap: [AppComponent],
  entryComponents: [ componentsToLoad ],
})
export class AppModule { }

当我使用 ng serve 编译时，我得到这个错误:

When I compile using ng serve, i get this error:

10% 构建模块 2/2 模块 0 activeError: 遇到错误静态解析符号值.不支持函数调用.考虑将函数或 lambda 替换为对导出函数，解析符号 AppModule 中D:/angularjs/test-app/src/app/app.module.ts，解析符号D:/angularjs/test-app/src/app/app.module.ts中的AppModule

10% building modules 2/2 modules 0 activeError: Error encountered resolving symbol values statically. Function calls are not supported. Consider replacing the function or lambda with a reference to an exported function, resolving symbol AppModule in D:/angularjs/test-app/src/app/app.module.ts, resolving symbol AppModule in D:/angularjs/test-app/src/app/app.module.ts

推荐答案

@NgModule({
    declarations: [],
    exports: []
})
export class testModule {
    static withComponents(components: any[]) {
        return {
            ngModule: testModule,
            providers: [
                {provide: ANALYZE_FOR_ENTRY_COMPONENTS, useValue: components, multi: true}
            ]
        }
    }
}

其他模块:

import { ComponentLoaderService } from './../../services/component-loader.service';

let componentsToLoad = ComponentLoaderService.getComponents();

@NgModule({
    imports: [
        BrowserModule,
        FormsModule,
        testModule.withComponents([
            ...componentsToLoad
        ])
    ],
    declarations: [
        AppComponent,
        ...componentsToLoad
    ],
    bootstrap: [AppComponent]
})
export class AppModule {
}

通过在此处使用 ANALYZE_FOR_ENTRY_COMPONENTS，您可以将多个组件动态添加到 NgModule.entryComponents 条目中.

By making use of ANALYZE_FOR_ENTRY_COMPONENTS here, you are able to add multiple components to the NgModule.entryComponents entry dynamically.

这篇关于使用服务动态加载 NgModule entryComponents的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！