How to bind web api data to form select option in Angular

Solution

It looks like your sys_id is an empty array.

I think you need to assign the data in your getSys() method.

 this.service.getSys(this.customer_id).subscribe((data) => {
  this.loading = true;
  console.log('Data' + data);

  for(var i = 0; i < data.length; i++){  // loop through the object array
       this.sys_id.push(data[i]);        // push each element to sys_id
  }

  this.loading = false;
  console.log('Result - ', data);
  console.log('data is received');
})