System.Collections.SortedList.SetByIndex C# (CSharp) Method

        public virtual void SetByIndex(int index, Object value)
        {
            if (index < 0 || index >= Count) throw new ArgumentOutOfRangeException(nameof(index), SR.ArgumentOutOfRange_Index);
            Contract.EndContractBlock();
            _values[index] = value;
            _version++;
        }

 public override void SetByIndex(int index, object value)
 {
     lock (host.SyncRoot)
     {
         host.SetByIndex(index, value);
     }
 }