,ArgumentOutOfRangeException: Index was out of range.

Questions & Answers
1

Error Message:
ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
`
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class ButtonManager : MonoBehaviour
{
#region Variables
[Header(“Scroll Settings”)]
[SerializeField] private Scrollbar scrollbarHorizontal;

[Header("Buttons Reference")]
[SerializeField] private GameObject bottomPanel;

private List<Button> bottomPanelButtonsList = new();
private List<float> scrollbarValuesList = new();

private int listCount;

private const float scrollbarValueForShop = 0f;
private const float scrollbarValueForLeaderboard = 0.25f;
private const float scrollbarValueForHome = 0.5f;
private const float scrollbarValueForFriends = 0.75f;
private const float scrollbarValueForSettings = 1;
#endregion

#region In-Built Functions
private void Awake()
{
    scrollbarHorizontal.value = scrollbarValueForHome;  //To always start from Home

    PopulateButtonList();
    PopulateScrollbarValueList();
}

private void Start()
{
    OnButtonClick();
}
#endregion

#region Custom Functions
private void PopulateButtonList()
{
    if (bottomPanelButtonsList != null)
    {
        bottomPanelButtonsList.AddRange(bottomPanel.GetComponentsInChildren<Button>());
        Debug.Log("Button List Populated");
    }
    else
    {
        bottomPanelButtonsList = new();
    }
}

private void PopulateScrollbarValueList()
{
    if (scrollbarValuesList != null)
    {
        scrollbarValuesList.Add(scrollbarValueForShop);
        scrollbarValuesList.Add(scrollbarValueForLeaderboard);
        scrollbarValuesList.Add(scrollbarValueForHome);
        scrollbarValuesList.Add(scrollbarValueForFriends);
        scrollbarValuesList.Add(scrollbarValueForSettings);
        Debug.Log("Float List Populated");
    }
    else
    {
        scrollbarValuesList = new();
    }
}

private void OnButtonClick()
{
    if (bottomPanelButtonsList.Count == scrollbarValuesList.Count)
    {
        listCount = bottomPanelButtonsList.Count;
        Debug.Log($"{listCount}");  //5
        for (int i = 1; i < listCount; i++)
        {
            //bottomPanelButtonsList[0].onClick.AddListener(() => scrollbarHorizontal.value = scrollbarValuesList[0]);
            //bottomPanelButtonsList[1].onClick.AddListener(() => scrollbarHorizontal.value = scrollbarValuesList[1]);
            //bottomPanelButtonsList[2].onClick.AddListener(() => scrollbarHorizontal.value = scrollbarValuesList[2]);
            //bottomPanelButtonsList[3].onClick.AddListener(() => scrollbarHorizontal.value = scrollbarValuesList[3]);
            //bottomPanelButtonsList[4].onClick.AddListener(() => scrollbarHorizontal.value = scrollbarValuesList[4]);

            bottomPanelButtonsList_.onClick.AddListener(() => scrollbarHorizontal.value = scrollbarValuesList*); //Error Here*_

}
}
}
#endregion
}
`
, using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class ButtonManager : MonoBehaviour
{
#region Variables
[Header(“Scroll Settings”)]
[SerializeField] private Scrollbar scrollbarHorizontal;

[Header(“Buttons Reference”)]
[SerializeField] private GameObject bottomPanel;

private List bottomPanelButtonsList = new();
private List scrollbarValuesList = new();

private int listCount;

private const float scrollbarValueForShop = 0f;
private const float scrollbarValueForLeaderboard = 0.25f;
private const float scrollbarValueForHome = 0.5f;
private const float scrollbarValueForFriends = 0.75f;
private const float scrollbarValueForSettings = 1;
#endregion

#region In-Built Functions
private void Awake()
{
scrollbarHorizontal.value = scrollbarValueForHome; //To always start from Home

PopulateButtonList();
PopulateScrollbarValueList();
}

private void Start()
{
OnButtonClick();
}
#endregion

#region Custom Functions
private void PopulateButtonList()
{
if (bottomPanelButtonsList != null)
{
bottomPanelButtonsList.AddRange(bottomPanel.GetComponentsInChildren());
Debug.Log(“Button List Populated”);
}
else
{
bottomPanelButtonsList = new();
}
}

private void PopulateScrollbarValueList()
{
if (scrollbarValuesList != null)
{
scrollbarValuesList.Add(scrollbarValueForShop);
scrollbarValuesList.Add(scrollbarValueForLeaderboard);
scrollbarValuesList.Add(scrollbarValueForHome);
scrollbarValuesList.Add(scrollbarValueForFriends);
scrollbarValuesList.Add(scrollbarValueForSettings);
Debug.Log(“Float List Populated”);
}
else
{
scrollbarValuesList = new();
}
}

private void OnButtonClick()
{
if (bottomPanelButtonsList.Count == scrollbarValuesList.Count)
{
listCount = bottomPanelButtonsList.Count;
Debug.Log($“{listCount}”); //5
for (int i = 1; i < listCount; i++)
{
//bottomPanelButtonsList[0].onClick.AddListener(() => scrollbarHorizontal.value = scrollbarValuesList[0]);
//bottomPanelButtonsList[1].onClick.AddListener(() => scrollbarHorizontal.value = scrollbarValuesList[1]);
//bottomPanelButtonsList[2].onClick.AddListener(() => scrollbarHorizontal.value = scrollbarValuesList[2]);
//bottomPanelButtonsList[3].onClick.AddListener(() => scrollbarHorizontal.value = scrollbarValuesList[3]);
//bottomPanelButtonsList[4].onClick.AddListener(() => scrollbarHorizontal.value = scrollbarValuesList[4]);

bottomPanelButtonsList_.onClick.AddListener(() => scrollbarHorizontal.value = scrollbarValuesList*);
}
}
}
#endregion*
}_

Error Message:
ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
System.Collections.Generic.List`1[T].get_Item (System.Int32 index) (at <9aad1b3a47484d63ba2b3985692d80e9>:0)
ButtonManager+<>c__DisplayClass14_0.b__0 () (at Assets/Scripts/ButtonManager.cs:88)

2

The exception tells you what the problem is and it will tell you the file, line and the character its happening on i.e.

ButtonManager.cs
line88

You are trying to use an item in an array using an index which is either to large or negative i.e. <=-1 or >=array.Length.

I suggest going to the line it tells you its happening on and fixing that