Xamarin.Forms中的多个阶梯状滑块

Question

I have a question about a multiple stepped sliders. I am trying to create multiple stepped sliders, but the problem is that I don't know how to identify which slider value is changed

This is my constructor:

 public FeedbackPage ()
        {
            InitializeComponent ();

            Feedback = new Feedback();

            StepValue = 1.0;

            SliderValueVak.ValueChanged += OnSliderValueChanged;
            SliderValueUitleg.ValueChanged += OnSliderValueChanged;

            this.BindingContext = this;
        }

As you can see if the value of a slider changes, it calls the OnSliderValueChanged method. The code inside this method is shown here below:

void OnSliderValueChanged(object sender, ValueChangedEventArgs e)
        {
            var newStep = Math.Round(e.NewValue / StepValue);

            SliderValueVak.Value = newStep * StepValue;
            SliderValueUitleg.Value = newStep * StepValue;
        }

But now if I use one slider, both slider values change, this is because I give them both the same value. Is there a way to use a if statement or swich case to see which slider value is changed?

Answer 1

sender is the control that fired the event. Simply cast it to the correct type and then you will know which slider was the source

void OnSliderValueChanged(object sender, ValueChangedEventArgs e)
    {
        var newStep = Math.Round(e.NewValue / StepValue);

        var slider = (Slider)sender;
        slider.Value = newStep * StepValue;
    }

Answer 2

As jason said, sender is the control that fired the event.But if you want to do some more .You can define a subclass of Slider

class MySlider:Slider
{
    public readonly int tag;
    public MySlider()
    {

    }

    public MySlider(int tag)
    {
        this.tag = tag;
    }

}

And you can set the tag to distinguish multiple stepped sliders.

SliderValueVak = new MySlider(10);
SliderValueUitleg = new MySlider(20);

Andin the method OnSliderValueChanged

void OnSliderValueChanged(object sender, ValueChangedEventArgs e)
{
   var newStep = Math.Round(e.NewValue / StepValue);

   MySlider slider = (MySlider)sender;

   if(slider.tag==10)// source is SliderValueVak
    {
      SliderValueVak.Value = newStep * StepValue;
      // do some thing more
    }

   else if(slider.tag == 20) //source is SliderValueUitleg
    {
      SliderValueUitleg.Value = newStep * StepValue;
      // do some thing more
    }

  }