从C#中的List <T>中删除重复项

List<T> list = new List<T>();
HashSet<T> set = new HashSet<T>(list);
List<T> uniqueList = set.ToList();

List<T> list = new List<T>();
List<T> uniqueList = list.Distinct().ToList();

List<T> list = new List<T>();
List<T> uniqueList = new List<T>();
foreach (T item in list)
{
    if (!uniqueList.Contains(item))
    {
        uniqueList.Add(item);
    }
}

List<T> list = new List<T>();
Dictionary<T, bool> dict = new Dictionary<T, bool>();
List<T> uniqueList = new List<T>();
foreach (T item in list)
{
    if (!dict.ContainsKey(item))
    {
        dict.Add(item, true);
        uniqueList.Add(item);
    }
}