将list集合中重复的元素只保留一个

    for (int i = 0; i < listRemove.Count; i++)

                {

                    for ( int j = listRemove.Count - 1;j>i;j--)

                    {

                        if (listRemove[i] == listRemove[j])

                        {

                            listRemove.RemoveAt(j);

                        }

                    }

                }