Checking dictionary for duplicate pairs

Questions & Answers
1

I’m trying to make a player editable keybinding menu.

The player clicks a button and they will be able to change the key binding.

I want to make sure the player hasn’t used the same key twice.

The debugs are there to see what the heck is going on with my code.

//Using OnGUI because it handles events
void OnGUI() {    

    //currentKey it the object that is clicked to indicate the player wants to change that key
    if (currentKey != null) {   
        Event e = Event.current;
        if (e.isKey) { //make sure it's a key press
           //create a dictionary that will be used later
           Dictionary<string, KeyCode> keysToReplace = new Dictionary<string, KeyCode>();

            Debug.Log(e.keyCode);
            myKeys[currentKey.name] = e.keyCode; // change the key to the new keyCode

            // check to see if any keys already have the same keyCode
            foreach (var item in myKeys) { 
                Debug.Log(item.Key + " " + item.Value);
                KeyCode itemValue = item.Value;
                if (itemValue == e.keyCode) {//if the itemValue is the same it's a duplicate
                    keysToReplace.Add(item.Key, KeyCode.Question); // add this pair as a duplicate
                    Debug.Log("Changed " + item.Key + " to question " + KeyCode.Question);
                } else { //the itemValue is not a duplicate
                    keysToReplace.Add(item.Key, item.Value); // add the pair as normal 
                    Debug.Log("Didn't Changed " + item.Key + " to question " + item.Value);

                }
            }
            // replace the dictionary with this new one that has been check for duplicate 
            myKeys = keysToReplace; 

            foreach (var item in myKeys) {
                Debug.Log("my keys: " + item.Key + " " + item.Value);
            }

            foreach (var item in keysToReplace) {
                Debug.Log("Keys to replace: " + item.Key + " " + item.Value);
            }

            ChangeButtonText(); //Change the button texts to show the player the change worked
            currentKey = null; //stop the player from making another change 
        }
    }
}
2

The answer was easier then I thought.

I was making it harder then it should have been. Since you can’t update a dictionary while it’s in a for loop you need to create a list with the keys that will be duplicates. Then iterate through that new list and change all the values of your dictionary.

   void OnGUI() {
    if (currentKey != null) {
        Event e = Event.current;
        if (e.isKey) {
            KeyCode ourKeyCode = e.keyCode;

            //Find if the keyCode is used by anyother keys and add to a temp list
            List<string> alreadyUsedList = new List<string>();
            foreach (var item in myKeys) {
                if (item.Value == ourKeyCode) {
                    alreadyUsedList.Add(item.Key);
                }
            }

            //If that key is used change that key to a question mark
            if (alreadyUsedList.Count > 0) {
                foreach (var alreadyUsedItem in alreadyUsedList) {
                    myKeys[alreadyUsedItem] = KeyCode.Question;
                }
            }

            myKeys[currentKey.name] = e.keyCode;
            ChangeButtonText();
            currentKey = null;
        }
    }
}