角度-如何在函数内设置值? [英] Angular - How to set the value inside the function?

问题描述

我无法设置 this.isHiddenColumnAvail 值.如何设置该值?

I am not able to set the this.isHiddenColumnAvail value. How to set this value?

checkHiddenRowAndColumns(file) {
    const workbook = new Excel.Workbook();
    const arryBuffer = new Response(file).arrayBuffer();
    arryBuffer.then(function (data) {
      workbook.xlsx.load(data)
        .then(function () {
          const worksheet = workbook.getWorksheet(1);

          //check hidden columns
          for(var i=0; i < worksheet.columns.length; i++) {
            if(worksheet.columns[i].hidden == true){
              this.isHiddenColumnAvail = true;
              break;
            }
          }

          //check hidden rows
          worksheet.eachRow(function (row,rowNumber) {
            if(row.hidden == true) {
              this.isHiddenColumnAvail = true;
            }
          });
        });
    });
  }

推荐答案

只需将函数更改为箭头函数即可.

It's simple you need to change the function to an arrow function.

使用箭头功能，您可以使用 this ，从而允许您访问外部/全局变量.

Using Arrow functions you can use this, allowing you access outside/global variables.

请参见下面的示例:

      worksheet.eachRow((row,rowNumber) => {
        if(row.hidden == true) {
          this.isHiddenColumnAvail = true;
        }
      });

在您的代码中，将其他功能替换为箭头功能

In your code, replace the other functions with arrow functions

观察:

• 在es6或更高版本中允许使用箭头功能

参考:

• https://medium.com/better-programming/常规功能和箭头功能之间的差异-f65639aba256
• https://262.ecma-international.org/6.0/#sec-arrow-function-definitions

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