如何使用EntityDataSource填充TreeView

Question

I use MS SQL, EF 4 and C#.

I have a table in SQL fro "Categories" and I need populate a TreeView in my Asp.net page.

My question are:

• 1 - How can i populate the TreeView?
• 2 - How can i use the TreeView to modify the hierarchy of my Categories?

NOTE: I use "hierarchyid" SQL Columns!

Thanks guys for your help!

    CREATE TABLE dbo.CmsCategories
(
    CategoryId          int             NOT NULL    IDENTITY (0,1)  -- Seed = 0 and Increment= 1
        CONSTRAINT PK_CmsCategories_CategoryId PRIMARY KEY,
    Title               nvarchar(40)    NOT NULL,
    MetaDescription     nvarchar(160)   NOT NULL,
    MetaKeyword         nvarchar(128)   NOT NULL,
    Summary             nvarchar(256)   NOT NULL,
    IsPublished         bit             NOT NULL
        CONSTRAINT DF_CmsCategories_IsPublished DEFAULT 1,  
    CategoryNode        hierarchyid     NOT NULL,
    CategoryNodeLevel AS CategoryNode.GetLevel()        
);

Answer 1

Unfortunately, EF4 doesn't support HierarchyId (yet). So in this case, your best bet would probably be to have a stored procedure that deals with your hierarchy and return a result set back to EF that EF4 can turn into a collection of user-defined complex type that can then be bound directly to the treeview control.

If you plan to update your hierarchy in the database, I would use the same approach: call a stored procedure from EF to update your hierarchy in the database.