Tutorial: Pass Parameter with Slider’s OnValueChanged() in Unity


This article would show how to pass parameters with UI events. Here we would make a UI text listening to a UI slider’s OnValueChanged() event to display its current value.


  • Unity 2017.1.1p3 (64-bit)

Step by Step

1. Create Callback Function in UI Text

We need to create a callback function for slider’s OnValueChanged(). Note that it must have a float parameter. Then add this script to your UI text.

public class OnValueChangedText : MonoBehaviour
    private Text ValueText;

    private void Start()
        ValueText = GetComponent<Text>();

    public void OnSliderValueChanged(float value)
        ValueText.text = value.ToString("0.00");

2. Add Callback Function to Slider’s OnValueChanged()

  • Drag the UI Text object into the slider’s OnValueChanged() panel in the inspector.

  • Select OnSliderValueChanged() function below Dynamic float label. Only functions matched the event’s parameters would show below this label.


The UI Text would receive every OnValueChanged() event with a float parameter now.

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