如何在formik中基于另一个字段设置一个字段的输入值? [英] How to set input value of one field based on another field in formik?

问题描述

我是ReactJS的新手，并在我的Web应用程序中使用了formik.在表单内部，我必须根据用户在另一个字段中输入的值来设置字段的值.

I am new to ReactJS and using formik in my web application. Inside the form, I have to set the value of a field based on the value entered by the user in another field.

以下是我的表格:

<Formik
   initialValues={this.state.data}
   enableReinitialize={true}
   onSubmit={this.formSubmit} >
   {({ values, setFieldValue }) => (
   <Form>
      <FormGroup>
         <Field className="form-control" name="Price" type="number">
         </Field>
         <Label className="impo_label">Price</Label>
      </FormGroup>
      <FormGroup>
         <Field className="form-control" name="Qty" type="number">
         </Field>
         <Label className="impo_label">Qty</Label>
      </FormGroup>
      <FormGroup>
         <Field className="form-control" value={values.Price*values.Qty} name="Amount" type="number">
         </Field>
         <Label className="impo_label">Amount</Label>
      </FormGroup>
      <FormGroup>
         <Field className="form-control" name="Discount" type="number">
         </Field>
         <Label className="impo_label">Discount</Label>
      </FormGroup>
      <FormGroup>
         <Field className="form-control" name="Discount" type="number">
         </Field>
         <Label className="impo_label">Discount</Label>
      </FormGroup>
      <FormGroup>
         <Field className="form-control" value={(values.Amount * values.Discount)/100} name="FinalAmount" type="number">
         </Field>
         <Label className="impo_label">FinalAmount</Label>
      </FormGroup>
   </Form>
   )}
</Formik>

在此表单中，我想基于用户输入的价格和数量来设置金额"值.为此，我使用了value = {values.Price * values.Qty}，该值在文本框中正确显示了该值，但未在values中设置该值.由于未正确评估FinalAmount的金额.

In this form, I want to set value for Amount based on the price and quantity entered by the user. For this, I have used value={values.Price*values.Qty}, that is showing the value properly in textbox but the value is not set in values.Amount due to which FinalAmount is not being evaluated properly.

我知道这里的问题，我必须使用setFieldValue来更新{values.Amount}.同样，我也必须将setFieldValue用于{values.FinalAmount}，并且在Price和Qty的更改上也是如此，因为更改价格或数量中的金额应同时反映在金额和最终金额中.另外，我必须在Discount更改时将setFieldValue用于FinalAmount.是否可以通过其他方法直接设置{values.Amount}和{values.FinalAmount}的值，而无需在更改价格，数量和折扣时编写setFeildValue.将value = {values.Price * values.Qty}用作金额"之类的内容应会更新{values.Amount}.

I know the issue here, I have to use setFieldValue to update the {values.Amount}.Likewise, I had to use setFieldValue for {values.FinalAmount} also and that too on the change of Price and Qty, because change in either price or qty should be reflected in both Amount as well as FinalAmount. Also, I have to use setFieldValue for FinalAmount on change of Discount. Is there any other way through which I can directly set the value for {values.Amount} as well as {values.FinalAmount} without writing setFeildValue on change of Price, Qty and Discount. Something like using value={values.Price*values.Qty} for Amount should update {values.Amount}.

推荐答案

最后，在尝试了各种方法之后，我得到了解决方案.我只是简单地将Amount和FinalAmount内部值属性设置为value={values.Amount = values.Price*values.Qty}.因此，在不使用setFieldValue的情况下更新了{values.Amount}字段.结果，基于{values.Amount}，正确评估了{values.FinalAmount}.我不知道我们可以像这样直接设置formik值，而无需使用setFieldValue.现在，我的最终形式为:

Finally, after trying various ways, I got the solution for this. I simply set the Amount and FinalAmount inside value attribute like value={values.Amount = values.Price*values.Qty}. So the {values.Amount} field was updated without using setFieldValue. As a result, based on {values.Amount}, {values.FinalAmount} was evaluated properly. I didn't knew we can set the formik values directly like this without using setFieldValue. Now my final form becomes:

<Formik
   initialValues={this.state.data}
   enableReinitialize={true}
   onSubmit={this.formSubmit} >
   {({ values, setFieldValue }) => (
   <Form>
      <FormGroup>
         <Field className="form-control" name="Price" type="number">
         </Field>
         <Label className="impo_label">Price</Label>
      </FormGroup>
      <FormGroup>
         <Field className="form-control" name="Qty" type="number">
         </Field>
         <Label className="impo_label">Qty</Label>
      </FormGroup>
      <FormGroup>
         <Field className="form-control" value={values.Amount = values.Price*values.Qty} name="Amount" type="number">
         </Field>
         <Label className="impo_label">Amount</Label>
      </FormGroup>
      <FormGroup>
         <Field className="form-control" name="Discount" type="number">
         </Field>
         <Label className="impo_label">Discount</Label>
      </FormGroup>
      <FormGroup>
         <Field className="form-control" name="Discount" type="number">
         </Field>
         <Label className="impo_label">Discount</Label>
      </FormGroup>
      <FormGroup>
         <Field className="form-control" value={values.FinalAmount = (values.Amount * values.Discount)/100} name="FinalAmount" type="number">
         </Field>
         <Label className="impo_label">FinalAmount</Label>
      </FormGroup>
   </Form>
   )}

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