Bug Dictionary.Clear() and Dictionary.Remove() do not do anything

In my FPS game, I made this code to save the player's binded controls into a dictionary that can be accessed by other scripts later on:

Code (CSharp):

1.     public void SaveControls()
2.     {
3.         ControlDictionary.Clear();
4.         foreach (Control CurrentControl in ControlArray)
5.         {
6.             ControlDictionary.Add(CurrentControl.Name, CurrentControl.Key);
7.         }
8.  
9.         ControlsCollectionScript.ControlArray = ControlArray;
10.  
11.         //Save ControlArray to a .json file//
12.         string ControlsJSON = JsonUtility.ToJson(ControlsCollectionScript);
13.         File.WriteAllText(Application.dataPath + "/controls.json", ControlsJSON);
14.         //Save ControlArray to a .json file//
15.     }

However, the script returned this error message:

ArgumentException: An item with the same key has already been added. Key: System.Collections.Generic.Dictionary`2[TKey,TValue].TryInsert (TKey key, TValue value, System.Collections.Generic.InsertionBehavior behavior) (at <9577ac7a62ef43179789031239ba8798>:0) System.Collections.Generic.Dictionary`2[TKey,TValue].Add (TKey key, TValue value) (at <9577ac7a62ef43179789031239ba8798>:0) ControlsManager.SaveControls () (at Assets/Scripts/ControlsManager.cs:228) ControlsManager.ResetAllControls () (at Assets/Scripts/ControlsManager.cs:97) ControlsManager.LoadControls () (at Assets/Scripts/ControlsManager.cs:203) ControlsManager.Awake () (at Assets/Scripts/ControlsManager.cs:24)

Which is very odd, considering that the very first thing the script does is clear the Dictionary before trying to add any keys to it. I tried using Dictionary.Remove() as well but to no avail:

Code (CSharp):

1. public void SaveControls()
2.     {
3.         ControlDictionary.Clear();
4.         foreach (Control CurrentControl in ControlArray)
5.         {
6.             ControlDictionary.Remove(CurrentControl.Name);
7.         }
8.  
9.         foreach (Control CurrentControl in ControlArray)
10.         {
11.             ControlDictionary.Add(CurrentControl.Name, CurrentControl.Key);
12.         }
13.  
14.         ControlsCollectionScript.ControlArray = ControlArray;
15.  
16.         //Save ControlArray to a .json file//
17.         string ControlsJSON = JsonUtility.ToJson(ControlsCollectionScript);
18.         File.WriteAllText(Application.dataPath + "/controls.json", ControlsJSON);
19.         //Save ControlArray to a .json file//
20.     }

Finally, I was able to get around this by checking in each individual key if it exists, and got around the problem.

Code (CSharp):

1.     public void SaveControls()
2.     {
3.         ControlDictionary.Clear();
4.  
5.         foreach (Control CurrentControl in ControlArray)
6.         {
7.             if (!ControlDictionary.ContainsKey(CurrentControl.Name))
8.             {
9.                 ControlDictionary.Add(CurrentControl.Name, CurrentControl.Key);
10.             }
11.         }
12.  
13.         ControlsCollectionScript.ControlArray = ControlArray;
14.  
15.         //Save ControlArray to a .json file//
16.         string ControlsJSON = JsonUtility.ToJson(ControlsCollectionScript);
17.         File.WriteAllText(Application.dataPath + "/controls.json", ControlsJSON);
18.         //Save ControlArray to a .json file//
19.     }

But this felt very wrong, as I am very clearly wiping out the Dictionary before using it. What is going on here? Is this just a bug?

 

You can verify that .Clear() is working by outputting ControlDictionary.Count just before the for loop. I guarantee it's working... if it didn't work, about a million projects would be broken.

I would hazard a guess that two of your controls have the same name. Try outputting each control's name just before they are added - I bet you'll see the same name twice there.