public void Add(string key, Vector2 val)
{
var dict = new Dictionary<string, Vector2>();
for (var i = 0; i < keys.Count; i++) {
var currentKey = keys[i];
var currentVal = values[i];
dict[currentKey] = currentVal;
}
// add or update parameter.
dict[key] = val;
keys = new List<string>(dict.Keys);
values = new List<Vector2>(dict.Values);
}