FireBaseHelper.cs

public async Task UpdatePerson(int personId, string name)  
        {  
            var toUpdatePerson = (await firebase  
              .Child("Persons")  
              .OnceAsync<Person>()).Where(a => a.Object.PersonId == personId).FirstOrDefault();  
  
            await firebase  
              .Child("Persons")  
              .Child(toUpdatePerson.Key)  
              .PutAsync(new Person() { PersonId = personId, Name = name });  
        }  
  
private async void BtnUpdate_Clicked(object sender, EventArgs e)  
        {  
            await firebaseHelper.UpdatePerson(Convert.ToInt32(txtId.Text), txtName.Text);  
            txtId.Text = string.Empty;  
            txtName.Text = string.Empty;  
            await DisplayAlert("Success", "Person Updated Successfully", "OK");  
            var allPersons = await firebaseHelper.GetAllPersons();  
            lstPersons.ItemsSource = allPersons;  
        }