Javascript Angular 2 - 绑定不能包含赋值
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Angular 2 - Bindings cannot contain assignments
提问by Nicolas
I need to give a class to a <tr>if a property of item has the same value as a property from an object in an array.
<tr>如果 item 的属性与数组中对象的属性具有相同的值，我需要为 a 提供一个类。
Here's the codeI currently have:
这是我目前拥有的代码：
<tr *ngFor="let item of closingDayGroupsList" [class.inactive]="definitionDetails.Groups.filter(i => i.AbsenceReservationGroupID === item.ID).length > 0">
however now I receive the error:
但是现在我收到错误：
Bindings cannot contain assignments
I'm not sure if what I'm doing is bad practice, or if I'm just making syntax errors.
我不确定我在做什么是不好的做法，或者我只是在犯语法错误。
This is the only way I know to achieve what I want, but it's not working
这是我所知道的实现我想要的唯一方法，但它不起作用
回答by Sravan
Its a bad practice to use expressionsin angular bindings
它是一种不好的做法，用expressions在angular bindings
Move the classexpressioninto controller.
将class表达式移动到控制器中。
export class AppComponent {
title = 'Groups';
getClass(item): void {
// add filter logic here
return this.definitionDetails.Groups.filter(i => i.AbsenceReservationGroupID === item.ID).length > 0
}
}
The tr will be something like,
tr 将是这样的，
<tr *ngFor="let item of closingDayGroupsList" [class.inactive]="getClass(item)">
回答by Shubham Dave
There is a little problem with that. Take as an example, that I want to stop showing the date to the user which is equal to 0000.00.00, so, by taking the inline expression binding I can find it right to:
这有点问题。举个例子，我想停止向用户显示等于 0000.00.00 的日期，所以，通过使用内联表达式绑定，我可以找到它：
{{(appointment_date === "0000.00.00") ? ' ' : appointment_date}} 