Angular：No component factory found for ChildComponent. Did you add it to @NgModule.entryComponents?

在使用 ngx-bootstrap/modal 弹出模态框时报下面错误：

ERROR Error: No component factory found for ChildComponent. Did you add it to @NgModule.entryComponents?

解决办法就是在 module.ts 里的 @NgModule 里追加 entryComponents: [ChildComponent]

@NgModule({
  entryComponents: [ChildComponent]
})