angular2管道模板解析错误

Question

我正在尝试使用管道实现简单的搜索。我对管道和 angular2 的概念真的很陌生，所以我需要你的帮助

这是我的html：

<input  type="textarea"  placeholder="branch" [(ngModel)]="search.branch" name="branch">
 <tr *ngFor="let loan of loans | loanfilter:search.branch ">
            <td><input type="checkbox"></td>
            <td>{{loan.loanId}}</td>
            <td>{{loan.custName}}</td>
            <td>{{loan.vehicleNum}}</td>
            <td>{{loan.TC}}</td>
            <td>{{loan.RE}}</td>
        </tr>

loan.component.ts：

import { Component } from '@angular/core';
import { LoanService } from '../../services/loans.service';
import { Loan } from '../../../loan';
import { Injectable, Pipe, PipeTransform } from '@angular/core';
import { LoanFilterPipe } from '../../pipes/loan.pipe';

@Component({
    moduleId: module.id,
    selector: 'loans',
    templateUrl: './loans.component.html',
    providers: [LoanService],
    declarations: [LoanFilterPipe]  //getting error on this line: Object literal may only specify known properties, and 'declarations' does not exist in type 'Component'.
})

export class LoansComponent{

    loans : Loan[];
    custName: any;

    constructor(private loanService: LoanService){
        this.getloans();
    };

    getloans(){
        this.loanService.getLoan()
            .subscribe(loans => {
                this.loans = loans;
                console.log(loans);
            });

    }
};

我得到的错误是：

未捕获（承诺中）：错误：模板解析错误：无法绑定到 'ngModel' 因为它不是 'input' 的已知属性

loan.pipe.ts：

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
    name: 'loanfilter'
})

export class LoanFilterPipe implements PipeTransform{
    transform(loans: any[], args: any): any{
        return loans.filter(item => item.title.indexOf(args[0].title) !== -1);
    }
}

我还使用了一个 module.ts 文件来声明管道和所有其他组件：

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

import { LoansComponent } from './components/loans/loans.component';
import { LoanFilterPipe } from './pipes/loan.pipe';
import { AppComponent }  from './app.component';

@NgModule({
  imports:      [ BrowserModule, HttpModule ],
  declarations: [ AppComponent, LoansComponent, LoanFilterPipe ],
  bootstrap:    [ AppComponent ],
  exports:      [LoanFilterPipe]
})

export class AppModule { }

Answer 1

正如其他答案所建议的，您必须导入 FormsModule

您还设置了search.branch 为未在组件打字稿文件中声明的ngModel。

而且您不必在组件装饰器中提供declarations 数组。 从@Component 中删除declarations: [LoanFilterPipe]。

它在 NgModule 中给出。除非你要在另一个模块中使用，否则不必将它放在导出中。

Answer 2

您的代码中缺少FormsModule

因为根据角度FormsModule，如果您使用ngModel，则必须在引导时添加，因为到目前为止，ngModel 是 FormModule 的一部分

Answer 3

在您的应用模块中导入FormsModule。

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

import { LoansComponent } from './components/loans/loans.component';
import { LoanFilterPipe } from './pipes/loan.pipe';
import { AppComponent }  from './app.component';

@NgModule({
  imports:      [ BrowserModule, HttpModule, FormsModule ],
  declarations: [ AppComponent, LoansComponent, LoanFilterPipe ],
  bootstrap:    [ AppComponent ],
  exports:      [LoanFilterPipe]
})

export class AppModule { }