方法'' 不支持转换为 SQL

本文关键字：SQL 不支持 方法 转换 | 更新日期: 2023-09-27 18:35:42

我想，在linq to sql查询where子句中，检查一个公共int。 我收到此错误：方法"Int32 isInDept（System.String）"不支持转换为SQL。

模糊相关的类（来自一个名为 ad 的公共静态类）： 

    //get AD property
    public static string GetProperty(this Principal principal, String property) {
        DirectoryEntry directoryEntry = principal.GetUnderlyingObject() as DirectoryEntry;
        if (directoryEntry.Properties.Contains(property))
            return directoryEntry.Properties[property].Value.ToString();
        else
            return String.Empty;
    }
    public static string GetDepartment(this Principal principal) {
        return principal.GetProperty("department");
    }

有问题的类（来自不同的类）：

    public int isInDept(string department) {
        PrincipalContext domain = new PrincipalContext(ContextType.Domain);
        UserPrincipal userPrincipal = UserPrincipal.FindByIdentity(domain, GetUserId());
        if (department == userPrincipal.GetDepartment()) {
            return 3;
        }
        else { return 2; }
    }
    public intranetGS.viewArticle viewArticle(int id) {
        string user = GetUserId();
        var result = ( from a in n.articles
                       join s in n.sections on a.section equals s.section_id
                       join p in n.privacies on a.privacy equals p.privacy_id
                       let iid = isInDept(s.name)
                       where (a.active == true && a.article_id == id && a.privacy < iid) ||
                       (a.active == true && a.article_id == id && a.privacy == 3 && a.author == user)
                       select new intranetGS.viewArticle {
                           articleId = a.article_id,
                           title = a.title,
                           author = a.author,
                           html = a.html,
                           section = s.name,
                           privacy = p.name,
                           dateCreated = a.date_created,
                           dateModified = a.date_modified,
                           userCreated = a.user_created,
                           userModified = a.user_modified
                       }).First();
        var nv = (from v in n.navs
                            join s in n.sections on v.section equals s.section_id
                            let iid = isInDept(s.name)
                            where (v.active == true && s.name == result.section && v.privacy  < 3) ||
                            (v.active == true && s.name == result.section && v.privacy == iid && v.user_created == user)
                            select v.html);
        StringBuilder sb = new StringBuilder();
        foreach (var r in nv) {
            sb.Append(nv);
        }
        result.articleNav = sb.ToString();
        return result;
    }

我做错了什么？ 如果我不能这样做，建议如何做？

方法'' 不支持转换为 SQL

不可能

将该函数转换为 SQL ，一种解决方法是使用 linq to sql 进行大部分查询，其余部分使用 Linq to Objects。它应该是这样的：

 var query = ( from a in n.articles
                       join s in n.sections on a.section equals s.section_id
                       join p in n.privacies on a.privacy equals p.privacy_id
                       where (a.active == true && a.article_id == id)
                       select new intranetGS.viewArticle {
                           articleId = a.article_id,
                           title = a.title,
                           author = a.author,
                           html = a.html,
                           section = s.name,
                           privacy = p.name,
                           privacyId = a.privacy,
                           dateCreated = a.date_created,
                           dateModified = a.date_modified,
                           userCreated = a.user_created,
                           userModified = a.user_modified
                       }).ToList();

然后过滤列表：

var result = query.Where(a => (a.privacyId < isInDept(a.section)) ||
                       (a.privacyId == 3 && a.author == user)).First();

然后，您可以对第二个查询执行相同的操作。

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