"InvalidCastException: Specified cast is not valid." Error

Questions & Answers
1

Hello there! I have a script that will create the menus in my game procedurally so I don’t have to make them all myself. It has all been working perfectly fine up until now, and I haven’t changed anything that should affect it. I am getting this error :

InvalidCastException: Specified cast is not valid.
BuildingMenus.ClearButtons (System.Boolean buildMenu) (at Assets/Scripts/Menus/BuildingMenus.cs:65)
BuildingMenus.DrawBuildMenu () (at Assets/Scripts/Menus/BuildingMenus.cs:48)
UnityEngine.Events.InvokableCall.Invoke () (at <4a29708cee654ac0aca16c9d5624806a>:0)
UnityEngine.Events.UnityEvent.Invoke () (at <4a29708cee654ac0aca16c9d5624806a>:0)
UnityEngine.UI.Button.Press () (at Library/PackageCache/com.unity.ugui@1.0.0/Runtime/UI/Core/Button.cs:70)
UnityEngine.UI.Button.OnPointerClick (UnityEngine.EventSystems.PointerEventData eventData) (at Library/PackageCache/com.unity.ugui@1.0.0/Runtime/UI/Core/Button.cs:114)
UnityEngine.EventSystems.ExecuteEvents.Execute (UnityEngine.EventSystems.IPointerClickHandler handler, UnityEngine.EventSystems.BaseEventData eventData) (at Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/ExecuteEvents.cs:57)
UnityEngine.EventSystems.ExecuteEvents.Execute[T] (UnityEngine.GameObject target, UnityEngine.EventSystems.BaseEventData eventData, UnityEngine.EventSystems.ExecuteEvents+EventFunction`1[T1] functor) (at Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/ExecuteEvents.cs:272)
UnityEngine.EventSystems.EventSystem:Update() (at Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/EventSystem.cs:501)

Quite a long one! The thing is, it only happens when I select the tab the SECOND time. So after the game objects are already there. The error is from the ClearButtons() method. My script is this:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using TMPro;

public class BuildingMenus : MonoBehaviour
{
    private BuildingManager buildingManager;
    private Decorating decorating;

    [SerializeField] private GameObject buttonPrefab;
    [SerializeField] private GameObject decorateButtonParent;
    [SerializeField] private GameObject buildButtonParent;
    [SerializeField] private GameObject buttonStart;
    GameObject previousButton;

    [SerializeField] private float offset;

    private Button[] buttons;

    void Start()
    {
        buildingManager = GameObject.Find("Building Manager").GetComponent<BuildingManager>();
        decorating = GameObject.Find("Building Manager").GetComponent<Decorating>();
    }

    public void DrawDecorateMenu()
    {
        previousButton = null;
        ClearButtons(false);
        foreach(DecorationAsset decoration in decorating.decorations)
        {
            if (decoration.unlocked)
            {
                if (previousButton == null) { previousButton = Instantiate(buttonPrefab, buttonStart.transform.position, transform.rotation, decorateButtonParent.transform); }
                else { previousButton = Instantiate(buttonPrefab, new Vector3(previousButton.transform.position.x + Screen.width/offset, previousButton.transform.position.y, previousButton.transform.position.z), transform.rotation, decorateButtonParent.transform); }
                previousButton.GetComponent<Image>().sprite = decoration.icon;
                previousButton.GetComponent<Button>().onClick.AddListener(delegate {decorating.SelectDecoration(decoration); });
                previousButton.name = decoration.name;
            }
        }
    }

    public void DrawBuildMenu()
    {
        previousButton = null;
        ClearButtons(true);
        foreach (CoursePieceAsset piece in decorating.coursePieces)
        {
            if (piece.unlocked)
            {
                if (previousButton == null) { previousButton = Instantiate(buttonPrefab, buttonStart.transform.position, transform.rotation, buildButtonParent.transform); }
                else { previousButton = Instantiate(buttonPrefab, new Vector3(previousButton.transform.position.x + Screen.width / offset, previousButton.transform.position.y, previousButton.transform.position.z), transform.rotation, buildButtonParent.transform); }
                previousButton.GetComponent<Image>().sprite = piece.icon[0];
                previousButton.GetComponent<Button>().onClick.AddListener(delegate { decorating.SelectCoursePiece(piece); });
                previousButton.name = piece.name;
            }
        }
    }

    public void ClearButtons(bool buildMenu)
    {
        if (buildMenu) {
            foreach (GameObject obj in buildButtonParent.transform) { Destroy(obj); }
        }
        else {
            foreach (GameObject obj in decorateButtonParent.transform) { Destroy(obj); }
        }
    }
}

I have tabs that you click on to switch between different sections of the building menu. Here is a screenshot of what one of the tabs click events look like if this is relevant at all:
190553-buttonevents.png

I am assuming that this is something that I have just completely missed and I am just being dumb, but I hope this is enough info to help! If you need to see anything else please let me know.

2

SOLVED BY SOMEONE ON A DISCORD SERVE I AM ON :
It is because transforms hold transforms not game objects, so I needed to change the GameObject in the loop to transform. I am sad that I didn’t realize this. Thank you to that person, you helped me a lot. Maybe one day, this will help someone else.