Angular2中的matDatePicker ngModal问题

这是我的Html代码

 <div>
    <mat-form-field>
        <input matInput [matDatepicker]="picker" placeholder="Choose a date" [(ngModal)]="picker"  >
        <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
        <mat-datepicker #picker></mat-datepicker>
    </mat-form-field>
    <button type="submit">Go</button>
</div>

我在ngModal中遇到问题。我得到以下错误

Unhandled Promise rejection: Template parse errors:
Can't bind to 'ngModal' since it isn't a known property of 'input'. (" <mat-form-field>
    <input matInput [matDatepicker]="picker" placeholder="Choose a date" [ERROR ->][(ngModal)]="picker"  >
    <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker"): 

    ng:///app/dashboard/dashboard.component.html@3:81 ; Zone: <root> ; 
    Task: Promise.then ; Value: Error: Template parse errors:


Can't bind to 'ngModal' since it isn't a known property of 'input'. (" <mat-form-field>
       <input matInput [matDatepicker]="picker" placeholder="Choose a date" [ERROR ->][(ngModal)]="picker"  >            
       <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker"): ng:///app/dashboard/dashboard.component.html@3:81

未处理的承诺拒绝：模板分析错误：
无法绑定到“ngModal”，因为它不是“input”的已知属性。(" 
][（ngModal）]=“选择器”>
正确的指令是NgModel，而不是NgModal

通常，出现错误的原因是定义指令的模块未导入组件的模块，或者指令选择器拼写错误

以下是官方文档的链接：
我已将ngModal更正为ngModel。这是我得到的错误。“未处理的承诺拒绝：无法分配给引用或变量！”区域：；任务：承诺。然后；值：错误：无法分配给引用或变量！"在模板中，您应该更改#picker reference Variable name，因为它已在组件类中定义。是的，我已将ngModel中的picker的名称更改为其他名称，现在可以使用了。谢谢。我找到了一个解决方案，ngModel名称不应与日期picker名称相同。我已将ngModel名称更改为fromDatePicker。这就是解决方案我解决了我的问题。
Unhandled Promise rejection: Template parse errors:
Can't bind to 'ngModal' since it isn't a known property of 'input'. (" <mat-form-field>
    <input matInput [matDatepicker]="picker" placeholder="Choose a date" [ERROR ->][(ngModal)]="picker"  >
    <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker"): 

    ng:///app/dashboard/dashboard.component.html@3:81 ; Zone: <root> ; 
    Task: Promise.then ; Value: Error: Template parse errors:


Can't bind to 'ngModal' since it isn't a known property of 'input'. (" <mat-form-field>
       <input matInput [matDatepicker]="picker" placeholder="Choose a date" [ERROR ->][(ngModal)]="picker"  >            
       <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker"): ng:///app/dashboard/dashboard.component.html@3:81