将ValueTuple转换为IEnumerable
有没有更好的方法来做到以下几点:
public static class ValueTupleAdditions {
public static IEnumerable<object> ToEnumerable<A, B>(this ValueTuple<A, B> tuple) {
yield return tuple.Item1;
yield return tuple.Item2;
}
public static IEnumerable<object> ToEnumerable<A, B, C>(this ValueTuple<A, B, C> tuple) {
yield return tuple.Item1;
yield return tuple.Item2;
yield return tuple.Item3;
}
[etc]
}
编辑:由于人们要求用例,在这里你去。
using Xunit;
namespace Whatever {
public class SomeTestClass {
public static IEnumerable<(string, Expression<Func<string, string>>, string)> RawTestData() {
yield return ("Hello", str => str.Substring(3), "lo");
yield return ("World", str => str.Substring(0, 4), "worl");
}
public static IEnumerable<object[]> StringTestData() {
return RawTestData().Select(vt => new object[] { vt.Item1, vt.Item2, vt.Item3 });
// would prefer to call RawTestData().Select(vt => vt.ToArray()) here, but it doesn't exist.
}
[Theory, MemberData(nameof(StringTestData))]
public void RunStringTest(string input, Expression<Func<string, string>> func, string expectedOutput) {
var output = func.Compile()(input);
Assert.Equal(expectedOutput, output);
}
}
}
有点反思:
namespace ConsoleApp1
{
using System;
using System.Collections.Generic;
using System.Linq;
public class Program
{
public static void Main()
{
var tuple = (1, 2, 3, 4, 5, 6, 7);
var items = ToEnumerable(tuple);
foreach (var item in items)
{
Console.WriteLine(item);
}
}
private static IEnumerable<object> ToEnumerable(object tuple)
{
if (tuple.GetType().GetInterface("ITupleInternal") != null)
{
foreach (var prop in tuple.GetType()
.GetFields()
.Where(x => x.Name.StartsWith("Item")))
{
yield return prop.GetValue(tuple);
}
}
else
{
throw new ArgumentException("Not a tuple!");
}
}
}
}
一种方法是通过ITuple
界面。
public interface ITuple
{
int Length { get; }
object this[int index] { get; }
}
它仅在.NET Core 2.0,Mono 5.0和下一版本的.NET Framework(未发布,接下来的4.7)中可用。 它不会(也永远不会)通过ValueTuple包作为旧框架的附加组件。
此API旨在供C#编译器在未来的模式工作中使用。
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