class YourClass
{
int Num;
List<string> Items
}


private YourClass Foo()
{
YourClass yc = new YourClass();
yc.Num = 0;
yc.Items = new List<string>();
yc.Items.Add("abc");
return yc;
}

------解决方案--------------------
第一种：

private List<T> Get(out int)
{}


第二种：

struct Test<T>
{
 int A {get;set;}
 List<T> List {get;set;}
}


private Test<T> Get()
{}