C# 泛型

（一）泛型類

public class GenericClassBase<X, Y, Z> where X : IComparable, new()
    where Y : B, new()
    where Z : class, new()
{

}
public class GenClass : GenericClassBase<A, BB, C> { }
public class A : IComparable
{
    public int CompareTo(object obj)
    {
        throw new NotImplementedException();
    }
}
public class BB : B { }
public class B { }
public class C { }

 

我的本意是要將一個實體參數轉換為泛型對象T返回，所以初次代碼就寫成下面這樣：

public static T GetObj<T>(Employee model)
        {
            T result = default(T);
if (model is T)
            {
                result = (T)model; //或者  result = model as T;
            }
return result;
        }

可是，編譯器提示無法將類型轉換為T,之前竟然沒碰到過這個問題。查了一下資料，原來，要這么寫：

public class GenericTest
    {
//public static T GetObj<T>(Employee model)
//{
//    T result = default(T);
//    if (model is T)
//    {
//        result = (T)model; //或者  result = model as T;
//    }
//    return result;
//}
public static T GetObj<T>(Employee model)
        {
            T result = default(T);
if (model is T)
            {
                result = (T)(object)model; //或 (T)((object)model);
            }
return result;
        }
    }

天殺的ms。