如何将Linq中GroupBy语法的结果绑定到实体到网格视图

Question

i have a table in my database called "Module_Menus_Menu" and the tables data are like this :

MenuID  ParentID    Name        URL
//===================================================
   1       0        Home        /Home
   2       0        Products    /Products
   3       0        Templates   /Templates
   4       2        Prod1       /Products/Cat1
   5       2        Prod2       /Products/Cat2
   6       3        Free        /Templates/Free
   7       3        Premium     /Templates/Premium

as you see this is my menu table and home, products,templates are first level menu and Prod1 is under products and prod2 too, now i want to show them in grid view(in admin area) just for listing them and i want to use GroupBy syntax to get the data and bind grid view like this :

Home

Products
Prod1
Prod2

Templates
Free
Premium

i searched and found a query :

var items = (from m in context.Module_Menus_Menu group m by m.ParentID into g select new
                    {
                       ParentID = g.Key,
                       Name = g.Select(n => n.Name),
                       MenuID = g.Select(i => i.MenuID),
                       URL = g.Select(u => u.URL)
                    }).ToList();

now when i bind it to grid view :

grdItems.DataSource = items;
grdItems.DataBind();

and result :

Name
System.Collections.Generic.List`1[System.String]    
System.Collections.Generic.List`1[System.String]    
System.Collections.Generic.List`1[System.String]

please help me

Answer 1

When the result is Systems.Collections.Generic.List, the databinding does not know where to associate properties in the list to which column so takes each row whose type is List. You need to set your datafield columns in your gridview.

    <columns>
      <asp:boundfield datafield="CustomerID" headertext="Customer ID"/>
      <asp:boundfield datafield="CompanyName" headertext="Company Name"/>
      <asp:boundfield datafield="Address" headertext="Address"/>
    </columns>