属性“ callproducts”在类型“ XMLHttpRequest”上不存在

Question

说明：我在项目中使用XMLHttpRequest。我想在获得状态时调用另一个函数。下面是我的home.ts代码。

从输入类型中选择文件时，会调用

onFileSelected(event)，除非我尝试调用此函数，否则一切正常  this.callproducts(data,0,c_altcode)

请指导我如何调用此功能

home.ts

     onFileSelected(event)
  {
    var file = event.target.files[0];
    var url = window.URL.createObjectURL(file);
        var oReq = new XMLHttpRequest();
        oReq.open("GET", url, true);
        oReq.responseType = "arraybuffer";

        oReq.onload = function(e) {
            var arraybuffer = oReq.response;


            var data = new Uint8Array(arraybuffer);

            var arr = new Array();
            for (var i = 0; i != data.length; ++i) arr[i] = String.fromCharCode(data[i]);
            var bstr = arr.join("");


            var workbook = XLSX.read(bstr, {
                type: "binary"
            });


            var first_sheet_name = workbook.SheetNames[0];


            var worksheet = workbook.Sheets[first_sheet_name];


            var final_arr = XLSX.utils.sheet_to_json(worksheet, {
              raw: true
          });


          if(oReq.status === 200)
          { 
            if(final_arr[0].hasOwnProperty("Altcode"))
            {
              var c_altcode =final_arr[0].hasOwnProperty("Altcode");
// error comming in this line. 
          this.callproducts(data,0,c_altcode);           
                }

          }
        }

        oReq.send(null);
  }


// This is my `callproducts()` which i want to call.
callproducts(data,index,srch)
  {
     // some code here
}

  

错误：类型'XMLHttpRequest'上不存在属性'callproducts'。