如何从C#数组中删除重复项？

int[] array = { 1, 2, 2, 3, 4, 4, 5 };
HashSet<int> set = new HashSet<int>(array);
int[] newArray = set.ToArray();

int[] array = { 1, 2, 2, 3, 4, 4, 5 };
int[] newArray = array.Distinct().ToArray();

int[] array = { 1, 2, 2, 3, 4, 4, 5 };
int[] newArray = new int[array.Length];
int index = 0;

foreach (int item in array)
{
    if (Array.IndexOf(newArray, item) == -1)
    {
        newArray[index] = item;
        index++;
    }
}
Array.Resize(ref newArray, index);