[英]Interfaces and methods with generic types
我有兩個小類, Pet
和Book
每個類都有幾個屬性,以及一個帶有類似方法的函數
public static List<T> GetSubSet<T>(List<T> incomingList)
{
var returnList = new List<T>();
Random r = new Random();
Console.WriteLine("Enter size of random subset: ");
int randomInt = 0;
int size = Convert.ToInt32(Console.ReadLine());
while (size > incomingList.Count)
{
Console.WriteLine("Size too large, enter smaller subset: ");
size = Convert.ToInt32(Console.ReadLine());
}
while (returnList.Count < size)
{
randomInt = r.Next(incomingList.Count);
if (!returnList.Contains(incomingList[randomInt]))
{
returnList.Add(incomingList[randomInt]);
}
}
return returnList;
}
它接受對象的通用列表並返回較小的子集。 該功能有效,並且可以攜帶Pet或Book對象。 我想用同樣的功能,包含PET和圖書類型列表上。 我知道如何做到這一點的最好方法是使用接口(繼承在這里沒有意義)。
interface ISubset<T>
{
IEnumerable<T> GetSubset();
}
當我在Pet類上實現接口時,它看起來像
class Pet : ISubset<Pet>
在我的主班我有一個寵物和書籍清單。 我想將這兩個都添加到ISubset
對象的列表中,以便可以對兩個都使用GetSubset函數。 但是,我無法聲明類似
List<ISubset<T>> list = new List<ISubset<T>>();
我收到錯誤消息'the type or namespace T could not be found
接口接受通用類型時,如何聲明ISubset對象的列表?
好,我有兩個清單
List<Pet> petList = new List<Pet>();
petList.Add(new Pet() { Name = "Mr.", Species = "Dog" });
petList.Add(new Pet() { Name = "Mrs.", Species = "Cat" });
petList.Add(new Pet() { Name = "Mayor", Species = "Sloth" });
petList.Add(new Pet() { Name = "Junior", Species = "Rabbit" });
List<Book> bookList = new List<Book>();
bookList.Add(new Book() { Author = "Me", PageCount = 100, Title = "MyBook" });
bookList.Add(new Book() { Author = "You", PageCount = 200, Title = "YourBook" });
bookList.Add(new Book() { Author = "Pat", PageCount = 300, Title = "PatsBook" });
如果要將這些列表一起添加到另一個列表中,類型應該是什么?
您只能使用List<object>
,但是如果要按照建議的方式進行操作,則需要創建一個帶有簽名的接口,該簽名涵蓋兩個類
public interface IGen
{
int A;
int Method;
}
然后在類中繼承/實現此接口
public class Pet : IGen
{
public int A { get; set; }
private int Method(){ ... }
}
public class Book : IGen
{
public int A { get; set; }
private int Method(){ ... }
}
然后您可以像這樣傳遞到GetSubSet
GetSubSet<IGen>(List<IGen> incomingList) { ... }
我希望這有幫助。
List<object>
應該可以正常工作。
以下在LinqPad中進行了測試
void Main()
{
List<Pet> petList = new List<Pet>();
petList.Add(new Pet() { Name = "Mr.", Species = "Dog" });
petList.Add(new Pet() { Name = "Mrs.", Species = "Cat" });
petList.Add(new Pet() { Name = "Mayor", Species = "Sloth" });
petList.Add(new Pet() { Name = "Junior", Species = "Rabbit" });
List<Book> bookList = new List<Book>();
bookList.Add(new Book() { Author = "Me", PageCount = 100, Title = "MyBook" });
bookList.Add(new Book() { Author = "You", PageCount = 200, Title = "YourBook" });
bookList.Add(new Book() { Author = "Pat", PageCount = 300, Title = "PatsBook" });
List<object> both = petList.OfType<object>().Union(bookList.OfType<object>()).ToList().Dump();
}
// Define other methods and classes here
public class Pet
{
public string Name { get; set; }
public string Species { get; set; }
}
public class Book
{
public string Author { get; set; }
public int PageCount { get; set; }
public string Title { get; set; }
}
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