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c# - CSharpScript.EvaluateAsync 无法识别枚举

问题描述

我正在使用CSharpScript.EvaluateAsync从字符串生成谓词。使用 string 和 int 变量可以正常工作，但是如果我尝试在字符串中传入枚举变量以进行转换，则会引发错误：

消息“（1,26）：错误CS0103：当前上下文中不存在名称'状态'”字符串

这是独立的复制品：

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.CodeAnalysis.CSharp.Scripting;
using Microsoft.CodeAnalysis.Scripting;

namespace PredicateParser
{
    class Program
    {
        static void Main(string[] args)
        {
            var albums = new List<Album>
            {
                new Album { Quantity = 10, Artist = "Betontod", Title = "Revolution", Status = Status.Offline},
                new Album { Quantity = 50, Artist = "The Dangerous Summer", Title = "The Dangerous Summer", Status = Status.Offline },
                new Album { Quantity = 200, Artist = "Depeche Mode", Title = "Spirit", Status = Status.Online },
            };


            var albumFilter1 = "album => album.Quantity > 20 && album.Quantity < 200"; //works fine
            var albumFilter2 = "album => album.Status == Status.Online"; //Throws exception

            var predicate1 = CreatePredicate<Album>(albumFilter1);
            var predicate2 = CreatePredicate<Album>(albumFilter2);

            var filteredAlbums1 = albums.Where(predicate1).ToList();
            var filteredAlbums2 = albums.Where(predicate2).ToList();

        }

        public static Func<T, bool> CreatePredicate<T>(string command)
        {
            var options = ScriptOptions.Default.AddReferences(typeof(T).Assembly);
            Func<T, bool> predicate = CSharpScript.EvaluateAsync<Func<T, bool>>(command, options).Result;

            return predicate;
        }

    }



    public class Album
    {
        public int Quantity { get; set; }
        public string Title { get; set; }
        public string Artist { get; set; }
        public Status Status { get; set; }
    }

    public enum Status
    {
        Online,
        Offline
    }
    
}

我怎样才能让它与枚举一起工作？

标签： c#roslyn

解决方案

var options = ScriptOptions.Default.AddReferences(typeof(T).Assembly).AddImports(nameof(PredicateParser));

您忘记添加“使用命名空间”:)

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