反应形式的自定义验证器控制数量 [英] Custom Validator Control Quantity in Reactive Forms

问题描述

我很难在 Angular 的响应式表单中实现自定义验证.我需要控制数量.数量不应超过可用数量.问题是如果每行都有子行，我怎么能得到所有数量的总和.我将如何计算子行的总数并将其与找到可用数量的父行进行比较.下面是我的代码.

I had a hard time implementing a custom validation in my reactive forms in Angular. I need to control the quantity. The quantity should not be more than the available quantity. The problem how can i get the total of all the quantity if each row has subrows. How will i able to compute the total of subrows and compare it to its parent row where the available quantity is found. Here's my code below.

这里还有我的代码链接请点击此链接

customValidator(campo1: string) {
    return (group: FormGroup): { [key: string]: any } => {
      const receive = group.controls[campo1];
       //Change this
      const available = 10;
      if (receive.value > available) {
        return {
          out: true
        };
      }
    }
  }

推荐答案

关键是使用parent"来访问 formArray.那么我们可以使用map对数组进行变换，只得到que的数量，reduce得到数量的总和

the key is using "parent" to reach the formArray. then we can use map to transform the array and get only que quantity and reduce to get the sum of the quantities

customValidator(campo1: string) {
    return (group: FormGroup): { [key: string]: any } => {
      //get the formArray
      const form=(group.parent as FormArray);
      if (form)
      {
        //get the available quantity using parent
        let available =form.parent.get('available_quantity').value;

        //the final available are the available less each quantity
        available=form.value //In form.value we have e.g. [{quantity:10..},{quantity:16}]
          .map(x=>x.quantity?+x.quantity:0)  //using map we have, e.g. [10,16]
          .reduce((a, b) => a - b, available)  //using reduce we substract the quantities to available
        if (available<0) {
          return {
            out: true
          };
        }
      }
    }
  }

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