Best Way to DataBind a List with sub-related content (For example, SO's questions with tags)

Question

Using ASP.net 2.0, how do I present the information to the user similar to the Questions list on SO where each question has some child items (like the tags).

I would pro

Answer 1

I would definitely avoid the second approach - you don't want to hit the database everytime you databind a parent item. As DOK says, try and architect your system properly. For me that would mean populating a collection of business objects and binding to it. I do something similar with a custom menu control (note this nests three datalists, but you could use repeaters):

In the aspx page:

            
             //your object

                
                
                //your object's child items

                    
                    
                       //child item's child items    
                    
                    

                
                 

            
            

then in the code behind:

protected void dlMenu_ItemDataBound(object sender, DataListItemEventArgs e)
{
    DataListItem parentList = e.Item;
    DataList dlMenuTwo = (DataList)parentList.FindControl("dlMenuTwo");
    MenuItem item = (MenuItem)parentList.DataItem;
    dlMenuTwo.DataSource = _menu.GetChildItems(item);
    dlMenuTwo.DataBind();
}

this method basically gets a reference to the object being bound (parentList.DataItem) and then binds the nested DataList to the child items (_menu.GetChildItems(item))