How can i solve the following problem? The left-hand side of an assignment must be a variable, a property or an indexer.

 using UnityEngine;
 
 public class ActivateTrigger : MonoBehaviour {
     public enum Mode {
         Trigger   = 0, // Just broadcast the action on to the target
         Replace   = 1, // replace target with source
         Activate  = 2, // Activate the target GameObject
         Enable    = 3, // Enable a component
         Animate   = 4, // Start animation on target
         Deactivate= 5 // Decativate target GameObject
     }
 
     /// The action to accomplish
     public Mode action = Mode.Activate;
 
     /// The game object to affect. If none, the trigger work on this game object
     public Object target;
     public GameObject source;
     public int triggerCount = 1;///
     public bool repeatTrigger = false;
     
     void DoActivateTrigger () {
         triggerCount--;
 
         if (triggerCount == 0 || repeatTrigger) {
             Object currentTarget = target != null ? target : gameObject;
             Behaviour targetBehaviour = currentTarget as Behaviour;
             GameObject targetGameObject = currentTarget as GameObject;
             if (targetBehaviour != null)
                 targetGameObject = targetBehaviour.gameObject;
         
             switch (action) {
                 case Mode.Trigger:
                     targetGameObject.BroadcastMessage ("DoActivateTrigger");
                     break;
                 case Mode.Replace:
                     if (source != null) {
                         Object.Instantiate (source, targetGameObject.transform.position, targetGameObject.transform.rotation);
                         DestroyObject (targetGameObject);
                     }
                     break;
                 case Mode.Activate:
                     targetGameObject.SetActive = true;
                     break;
                 case Mode.Enable:
                     if (targetBehaviour != null)
                         targetBehaviour.enabled = true;
                     break;    
                 case Mode.Animate:
                     targetGameObject.animation.Play ();
                     break;    
                 case Mode.Deactivate:
                 targetGameObject.SetActive = true;
                     break;
             }
         }
     }
 
     void OnTriggerEnter (Collider other) {
         DoActivateTrigger ();
     }
 }