Solution: this.$refs refers to subcomponents and reports an error is not a function

Solution: this.$refs refers to subcomponents and reports an error is not a function

• Description of the problem:
  Vue refers to subcomponents through this.$refs, and there is an error of undefined or is not a function

• The error is as follows:
  _this3.$refs.fileUpload.changeFileList is not a function

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problem analysis:

• Problem 1: An undefined error occurs

  1. The tag containing the sub-component needs to be placed in the sub-tag of the first sub-tag, and the ref attribute needs to be set,

     Because the logic code of the parent component calls the method or property of the child component through this property.

• Question 2: There is an error of is not a function

  1. Subcomponents need to be imported, please make sure the path is correct when importing
  2. After import, you need to register in the component of the parent component

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Solution:

• According to the above analysis, the seat number can be modified.

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