C# 如果项目不在数组中

我有一个包含这 3 项的数组：

string[] departmentArray = {
    "Warranty Service Representative",
    "Warranty Service Administrative Manager",
    "Warranty and Site Administrator"
};

我有这个字符串

var department = "Warranty Service Representative"

我有这个条件，应该测试字符串部门是否不在departmentArray

if (Array.Exists(departmentArray, element => element != department)){
}

显然该字符串在数组中，因此它应该返回 false，但这对于我的字符串返回 true。我究竟做错了什么？

这不是更简单吗？

string[] departmentArray = { 
    "Warranty Service Representative", 
    "Warranty Service Administrative Manager", 
    "Warranty and Site Administrator" };

String department = "Warranty Service Representative";

if (departmentArray.Contains(department) == false)
{
}