两个枚举列表的联合不会产生不同的项目？

Question

With

        var test = new RarityEnum[] { RarityEnum.Uncommon };
        var test2 = new RarityEnum[] { RarityEnum.Uncommon };
        var test3 = test.Union(test2);

Why is the test3 only containing 1 item and not 2?

How should I change this so it properly produces a new list of enums (even if the same enum value is present multiple times)?

I could cast to int before Union then cast back to enum after...is that the cleanest? I feel casting is not so pretty

Answer 1

From Microsoft's documentation on Union : "This method excludes duplicates from the return set. This is different behavior to the Concat method, which returns all the elements in the input sequences including duplicates."

In this example:

var test = new string[] { "cat" };
var test2 = new string[] { "cat" };
var test3 = test.Concat(test2);
var test4 = test.Union(test2);

test3 ends up being { "cat", "cat" }

test4 is just { "cat" }