通过消除给定节点和子节点，使用LINQ检索分层数据

Question

CREATE TABLE [dbo].[Folder](
    [FolderID] [int] IDENTITY(100,1) NOT NULL,
    [FolderName] [nvarchar](100) NOT NULL,
    [Description] [nvarchar](100) NULL,
    [ParentFolderID] [int] NULL,
    [IsDeleted] [bit] NULL CONSTRAINT [DF_Folder_IsDeleted]  DEFAULT ((0)),
    [OwnerUserID] [int] NULL,
    [ModifiedDate] [datetime] NULL,
PRIMARY KEY CLUSTERED 
(
    [FolderID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

FolderID FolderName描述ParentFolderID IsDeleted OwnerUserID修改日期 100 T desc NULL False
101 T-C1 100
102 T-C2 100
103 T-C1-C1 101
104 T-C1-C2 101
105 T-C2-C1 102
106 T-C3 100
107 T-C1-C2-C1 104

Treeview格式的数据   用户输入：101 以分层格式检索所有记录，但删除ID为101且子项低于101的记录。需要Linq查询。

Answer 1

尝试从这开始：

var lookup =
    Folder
        .Select(x => new
        {
            x.FolderID,
            x.ParentFolderID,
        })
        .Where(x => x.FolderId != 101)
        .ToLookup(x => x.ParentFolderID);

您可以使用lookup[100]访问顶级文件夹。然后递归调用lookup[x.FolderID]来遍历树。