Question

考虑我们有这个表，因为你可以看到我们保持文章状态的字符串字段

ArticleState可以是New，Draft或Published

USE [test]
GO

CREATE TABLE [dbo].[Article](
    [id] [int] NOT NULL PRIMARY KEY CLUSTERED,
    [ArticleState] [nvarchar](100) NOT NULL,
    [Title] [nvarchar](255) NOT NULL,
    [Content] [nvarchar](max) NOT NULL
)

GO

INSERT INTO Article VALUES (1,'New','title1','this is a test');
INSERT INTO Article VALUES (2,'Draft','title2','this is a test');
INSERT INTO Article VALUES (3,'New','title3','this is a test');
INSERT INTO Article VALUES (4,'Published','title4','this is a test');
GO

我们有这个枚举

public enum ArticleStateEnum
    {
        [EnumDescription("Draft Articles")]
        Draft = 10,

        [EnumDescription("New Articles")]
        New = 20,

        [EnumDescription("Published Articles ")]
        Published = 30,
    }

我们如何根据ArticleState选择文章？我的意思是我可以写什么而不是什么？

    // GET: Articles
    public ActionResult Index()
    {
      var result=  GetArticlesByState(ArticleStateEnum.Draft);
        return View(result);
    }
    public void GetArticlesByState(ArticleStateEnum nse)
    {

        var articleList = db.Articles.Where(x => x.ArticleState ==  ??????????????????????????????);
    }

Answer 1

假设您无法更改数据库表示，您只需使用ToString调用获取字符串值：

public void GetArticlesByState(ArticleStateEnum nse)
{
    string stateText = nse.ToString();
    var articleList = db.Articles.Where(x => x.ArticleState == stateText);
    ...
}

Answer 2

我会使用Enum.GetName(typeof(ArticleStateEnum), nse)

要么：

public void GetArticlesByState(ArticleStateEnum nse)
{
    var articleList = db.Articles
         .Where(x => x.ArticleState == Enum.GetName(typeof(ArticleStateEnum), nse));
}

或者喜欢：

public void GetArticlesByState(ArticleStateEnum nse)
{
    string state = Enum.GetName(typeof(ArticleStateEnum), nse);
    var articleList = db.Articles.Where(x => x.ArticleState == state);
}

请注意，此解决方案即使使用int值也能正常工作（只要该值与枚举值匹配）：

public void GetArticlesByState(int nse)
{
    string state = Enum.GetName(typeof(ArticleStateEnum), nse);
    var articleList = db.Articles.Where(x => x.ArticleState == state);
}

选择基于enum参数而不用swich case？

2 个答案: