先附上code class TestA { public int ID { get; set; } public string Name { get; set; } public int Age { get; set; } } class TestB : TestA { public string CName { get; set; } } class Program { static void Main(string[] args) { TestA ta = getTestA(); TestB tb = getTestA() as TestB; var temp = tb; } private static TestA getTestA() { return new TestA() { ID = 1, Name = "AA", Age = 18 }; } } 目的是讓TestB繼承的屬性直接給值而不用在B那邊一個一個寫入 爬了一天文沒找到相關的資訊及解法 求有沒有相類似的關鍵字讓小弟可以去查