C# 俩个字符串数据进行对比取出不同的数据

string sel_JD = "电冰箱，电热水壶，客厅空调，饮水机，";
string Operation_JD = "电冰箱，电热水壶，电动汽车，";
List<string> select_operation = new List<string>();
string[] sel_arr = sel_JD.Split('，');
IEnumerable<string> nameQuery = from name in sel_arr
select name;
string result = "";
foreach (string tt in nameQuery)
{
if (!Operation_JD.Contains(tt))
{
result += tt+";";
}
}
result = result.Substring(0, result.Length - 1);
Console.WriteLine(result);