Passing an int to a function from an onClick event gives the same value on every button.

So I'm calling this to make a bunch of buttons with different resolutions on them and set an onClick event on them that calls the function after it.

             for (int x = resString.Length-1; x >= 0; x--)
             {
                 GameObject newButton = (GameObject)Instantiate(resolutionButton);
                 newButton.transform.SetParent(resolutionPanel);
                 newButton.transform.localPosition = Vector3.zero;
                 newButton.transform.localScale = Vector2.one;
                 newButton.name = x.ToString();
                 newButton.transform.FindChild("Text").GetComponent<Text>().text = resString[x];
                 checks[x] = newButton.transform.FindChild("Check").GetComponent<Image>();
                 checks[x].enabled = (currentRes == x);
                 int newResInt = x;
                 Debug.Log(newResInt);
                 newButton.GetComponent<Button>().onClick.AddListener(
                 () => { SetResolutionIndex(newResInt, newButton); }
                 );
             }
     public void SetResolutionIndex(int theNewIndex, GameObject thisButton)
     {
         Debug.Log("New Index:" + EventSystem.current.currentInputModule.name);
         checkSelectedIndex = theNewIndex;
         DoChecks();
     }

But I have a problem with the int. It seems that it is using the last set value of "x" on every button (so in this case, 0), even though I am creating a new local integer, newResInt, to pass into the function. I've looked into this issue already, and people have said that should fix it, however, newResInt still seems to be a pointer to x. What am I doing wrong?