C# 泛型

（一）泛型类

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 { }

我的本意是要将一个实体参数转换为泛型对象T返回，所以初次代码就写成下面这样：

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，编译器提示无法将类型转换为T,之前竟然没碰到过这个问题。查了一下资料，原来，要这么写：

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;
        }
    }

天杀的ms。