Javascript Facing error core.js:15723错误类型错误：无法读取属性'；toLowerCase'；角度7中未定义的

下面我提到了我正在使用lazyLoading模块的代码。 所以请检查我的代码并更正我。facing TypeError:无法读取Angular 7中未定义的属性“toLowerCase”。 下面是添加模型类。我想知道我在代码中犯了什么错误，请纠正我

模范班

export class C_data {
productId:number;
product:string;
code:string;
available:string;
price:number;
rating:number;
productImage:string;
}

allData-page.component.ts

import {C_data} from '../../shared/model/c_data';
import { AllDataService } from './allData.service';
import { Observable } from 'rxjs';
@Component({
selector: 'all-data',
templateUrl: './alldataPage.component.html'
})

export class AlldataPageComponent implements OnInit {

    cdata:Observable<C_data[]>;

    constructor(private _allDataService: AllDataService) { }

    ngOnInit() { 
        this._allDataService.getData().subscribe(data => this.cdata)
        console.log(this.cdata);
    }
}

alldata.module.ts

import { AlldataPageComponent } from './allData-page.component';
import { CommonModule } from '@angular/common';
import { AllDataRouterModule } from './allData-routing.module';
import {  HttpClientModule } from '@angular/common/http';

@NgModule({
    imports: [
        CommonModule,
        AllDataRouterModule,
        HttpClientModule
    ],
    exports: [],
    declarations: [AlldataPageComponent]
})
export class AllDataModule { }

import { NgModule } from '@angular/core';
import { AlldataPageComponent } from './allData-page.component';

export const routes: Routes = [
    {
        path:'',
        component: AlldataPageComponent,
        data:{
            title:'data-table'
        }
    }
]

@NgModule({
    imports: [RouterModule.forChild(routes)],
    exports: [RouterModule],
    declarations: [],
})
export class AllDataRouterModule { }

allData-routing.module.ts

import { AlldataPageComponent } from './allData-page.component';
import { CommonModule } from '@angular/common';
import { AllDataRouterModule } from './allData-routing.module';
import {  HttpClientModule } from '@angular/common/http';

@NgModule({
    imports: [
        CommonModule,
        AllDataRouterModule,
        HttpClientModule
    ],
    exports: [],
    declarations: [AlldataPageComponent]
})
export class AllDataModule { }

import { NgModule } from '@angular/core';
import { AlldataPageComponent } from './allData-page.component';

export const routes: Routes = [
    {
        path:'',
        component: AlldataPageComponent,
        data:{
            title:'data-table'
        }
    }
]

@NgModule({
    imports: [RouterModule.forChild(routes)],
    exports: [RouterModule],
    declarations: [],
})
export class AllDataRouterModule { }

应该是：

urls='../../shared/services/modeldata.json';

不是

应该是：

urls='../../shared/services/modeldata.json';

不是

---

您正在模板中调用

toLowerCase

？我在你的代码中没有看到它。你在模板中调用

toLowerCase

？我在你的代码里没看到