扩展方法泛型VB到C#

Imports System.Runtime.CompilerServices

Public Module StringExtensions
    <Extension()>
    Public Function ReverseString(str As String) As String
        Return New String(str.Reverse().ToArray())
    End Function
End Module

using System;
using System.Linq;

public static class StringExtensions
{
    public static string ReverseString(this string str)
    {
        return new string(str.Reverse().ToArray());
    }
}

Imports System.Runtime.CompilerServices

Public Module ListExtensions
    <Extension()>
    Public Function FirstOrDefault(Of T)(list As List(Of T), predicate As Func(Of T, Boolean)) As T
        Return list.Where(predicate).FirstOrDefault()
    End Function
End Module

using System;
using System.Collections.Generic;
using System.Linq;

public static class ListExtensions
{
    public static T FirstOrDefault<T>(this List<T> list, Func<T, bool> predicate)
    {
        return list.Where(predicate).FirstOrDefault();
    }
}

using YourNamespace;

var result = list.FirstOrDefault(item => item.Id == 1);