Variable gets overwritten when changing from OnDrag() to OnDrop()

Hi everyone,

I'am using the unity event system for my drag & drop functionality in my inventory. I experienced a change of the variable value between the "drag calls": OnBeginDrag(), OnDrag(), OnEndDrag() and the "drop call" OnDrop(). I created an example to show the problem:

• created a scrpit 'TestDragDrop'

• script is attached to two identical gameobjects Rect and Rect(1) which are placed in the scene, see:

Inspector of Rect(1) (identical to Rect):

TestDragDrop(Script) - working principle:

• In Start() I declare _testNumber = 3

• OnBeginDrag() sets _testNumber = 5

• during OnDrag() dragged gameobject (Rect or Rect(1) follows mouse cursor

• OnDrop() gets called when dropping Rect on Rect(1) or vice versa

• OnDrop() output says _testNumber = 3 <-- Why??? (i want it to be: _testNumber = 5)

• output of OnEndDrag() says _testNumber = 5 <-- okay

I hope somebody can help me. If I forgot some information feel free to ask me :).

Here the complete script:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.EventSystems;
 
 using UnityEngine.UI;
 
 public class TestDragDrop : MonoBehaviour, IBeginDragHandler, IDragHandler, IDropHandler, IEndDragHandler
 {
 
     private int _testNumber;
 
     // Use this for initialization
     void Start()
     {
         Debug.Log("Start");
         _testNumber = 3;
     }
 
     
     public void OnBeginDrag(PointerEventData eventData)
     {
         Debug.Log("OnBeginDrag");
         _testNumber = 5;
         Debug.Log("_testNumber = " + _testNumber);
 
         GetComponent<CanvasGroup>().blocksRaycasts = false;
         GetComponent<Image>().raycastTarget = false;
     }
 
 
     public void OnDrag(PointerEventData eventData)
     {
         Debug.Log("OnDrag");
         Debug.Log("_testNumber = " + _testNumber);
 
         // mouse Coordinates need to be converted to World coordinates
         var mouseCoordinates = Input.mousePosition;
         // use the inverted z-coordinate to make sure object gets displayed 
         // in front of the camera
         mouseCoordinates.z = -GameObject.Find("MainCamera").transform.position.z;
         transform.position = Camera.main.ScreenToWorldPoint(mouseCoordinates);
     }
 
 
     public void OnDrop(PointerEventData eventData)
     {
         Debug.Log("OnDrop");
         Debug.Log("_testNumber = " + _testNumber);
     }
 
 
     public void OnEndDrag(PointerEventData eventData)
     {
         Debug.Log("OnDragEnd");
         Debug.Log("_testNumber = " + _testNumber);
 
         GetComponent<CanvasGroup>().blocksRaycasts = true;
         GetComponent<Image>().raycastTarget = true;
     }
 
 
 }