Is it possible that ValueChanges are not being triggered when a value is assigned to the dropdown via the backend system?

Question

Is it possible that ValueChanges are not being triggered when a value is assigned to the dropdown via the backend system?

When working with an angular form to manage employee details, I encountered a scenario where the valueChanges.subscribe() method was instrumental in detecting changes in dropdown values when adding new employees.

    this.createEmpForm.get('employee_id').valueChanges.subscribe(value => {
            ...
        });

However, during editing mode, a backend error would occur if attempting to save data after changing the value of a specific user's dropdown/input box without physically clicking on the dropdown. This happened because, even though the data was pre-populated from the backend, the valueChanges.subscribe() event did not trigger since the default dropdown state wasn't altered. How can this issue be resolved?

angular typescript angular-forms

Answer 1

Answer №1

If you prefer, you can directly access the data

updateEmployeeInfo({emp_id: this.createEmpForm.get('employee_id').value})

Alternatively, you have the option to send the entire form content or specific parts

const formData = this.form.value
sendToServer(formData)

You can also initialize with the current value

this.createEmpForm.get('employee_id').valueChanges.pipe(
         startWith(this.createEmpForm.get('employee_id').value)
    ).subscribe(data => {
        ...
    });

Answer 2

If you prefer, you can directly access the data

updateEmployeeInfo({emp_id: this.createEmpForm.get('employee_id').value})

Alternatively, you have the option to send the entire form content or specific parts

const formData = this.form.value
sendToServer(formData)

You can also initialize with the current value

this.createEmpForm.get('employee_id').valueChanges.pipe(
         startWith(this.createEmpForm.get('employee_id').value)
    ).subscribe(data => {
        ...
    });

Is it possible that ValueChanges are not being triggered when a value is assigned to the dropdown via the backend system?

Answer №1

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