Union合并数组（去掉重复的项目）

　　　string[] a = {"a", "b"};

            string[] b = { "b", "c", "d" };

            var data = (from t1 in a select t1).Union(from t2 in b select t2);
            foreach (var str in data)
            {
                MessageBox.Show(str);
            }