我有这样的代码:
using System;
using System.Collections.Generic;
using System.Linq;
public interface IMyString
{
string Id {get;set;}
};
public class MyString : IMyString
{
public string Id {get;set;}
}
public static class Extensions
{
public static IEnumerable<IMyString> WithId(this IEnumerable<IMyString> source,string id)
{
return source.Where(x => x.Id == id);
}
}
public class Program
{
private static List<T> GetMyStrings<T>(string key,List<T> input)
where T: IMyString
{
return input.WithId(key).ToList();
}
public static void Main()
{
var foo = new List<MyString>{ new MyString { Id = "yes"},new MyString { Id = "no" } };
var result = GetMyStrings("yes",foo);
var result2 = foo.WithId("no");
Console.WriteLine(result2);
}
}
为什么input.WithId(key).ToList()
可以,但foo.WithId("no")
会导致语法错误?有没有办法使方法GetMyStrings
起作用?