How do I reference button clicked to use in IndexOf

I’m trying to use a reference to a Button to get its position in a List of Buttons.

I have an OnClick function attached to multiple buttons. I have made a List of these buttons so that I can do other things with them by referencing them by their index numbers. I am having trouble figuring out how to get the index of the button that was clicked. I want to use IndexOf but I can’t figure out what to use to reference the button inside of IndexOf. I have read through many pages of documentation and searched results but haven’t been able to wrap my head around it.

Do I need to use AddListener? Do I need to use UnityEngine.EventSystems? Any input is appreciated. Here’s an example of my script:

public void SelectThisButton() {

    //try and get the index of the button pressed
    buttonIndex = buttonList.IndexOf( what goes in here? );

    //use the index of the button pressed for stuff
    buttonSprite = buttonList[buttonIndex].GetComponent<Image>().sprite;

    //do other stuff

}

Why over complicate it? If all you what to do is retrieve the sprite image from the button clicked, this will work

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class ButtonHandler : MonoBehaviour
{
    public void ButtonPressed (Button button)
    {
        if ((button != null) && (button.image != null) && (button.image.sprite != null))
        {
            Debug.Log("Button image/sprite = " + button.image.sprite.name);
            
            Sprite buttonSprite = button.image.sprite;

            // do other stuff
        }
    }
}

You will of course have to set each button OnClick() event in the inspector like so


Here I attached ButtonHandler.cs to the canvas with all the buttons. Then on each button I first selected the Canvas. Then I selected the ButtonHandler.ButtonPressed() function. Then I selected the Button as shown in the image (in this case it was “Button (3)”).

When the button is pressed the button is passed to the function where you can retrieve the sprite and do what you want with it.

If you still have a need to use a list for some reason you can do a look up based on the sprite name.