Nested Repeaters in ASP.NET

Question

I have a class that contains hierarchical data. I want to present this data in my ASP.net webapp using nested repeaters. How do I do this? I've only ever done one level of nesting, how do I do say five levels?

Each item can have zero or many sub items. I'm basically just indenting at each subleveling using some css stuff. I do not want to use the treeview control, I want to strictly stick with a repeater.

Update:
My data comes from a database. I have an item datatable with some basic properties.

Item {    ID,    Name,    Description,    ... } 

Then I have a many to many table with:

Parent {    ParentID,    ChildID } 

I'm iterating through each item and displaying its children; and its children's children. I assume this would best be accomplished with nested repeaters, but I could be wrong.

Answer 1

I've found that the simplest way to do nested repeaters without worrying about databinding events is to just set the DataSource using <%# %> syntax.

For example:

<asp:Repeater runat="server" id="Departments">   <ItemTemplate>     Name: <%# Eval("DeptName") %>     Employees:     <asp:Repeater runat="server" DataSource='<%# Eval("Employees") %>'>       <ItemTemplate><%# Eval("Name") %></ItemTemplate>       <SeparatorTemplate>,</SeparatorTemplate>     </asp:Repeater>   </ItemTemplate> </asp:Repeater> 

This is presuming that your Departments class has an Employees property - eg:

public class Department {   public string DeptName {get; set;}   public IEnumerable<Employee> Employees {get; set;} } public class Employee {   public string Name {get; set;} } 

If your outer-repeater object doesn't have a property corresponding to the inner-repeater object you can still use this trick, by adding a method in your code-behind that does the calculation. So your inner repeater might become:

<asp:Repeater runat="server" DataSource='<%# GetEmployees(Container.DataItem) %>'> 

and then GetEmployees might look something like:

protected IEnumerable<Employee> GetEmployees(object item) {   var dept = (Department) item;   // then do whatever is necessary to get the employees from dept   return employees; } 

Answer 2

It's always cleaner to deal with the datasource than messing about with ItemDataBound, but this is even more the case when nesting Repeaters:

<asp:Repeater DataSource="<%#ColOfCol%>" runat="server">   <ItemTemplate>     <tr>       <asp:Repeater DataSource="<%#Container.DataItem%>" runat="server">         <ItemTemplate>           <td><%#SomeExtractingMethodLikeEval()%></td>         </ItemTemplate>       </asp:Repeater>     </tr>   </ItemTemplate> </asp:Repeater> 

The inner datasource could also be an evaluated property, or a call to a method that returns the enumeration wanted. Just be aware that it will be called with an object. I prefer to write the specific version, and then overload:

protected IEnumerable<string> GetNames(Family fam) {   foreach(Person p in fam.Members)     yield return p.FirstName + " " + p.Surname; } protected IEnumerable<string> GetNames(object famObj) {     return GetNames((Family)famObj); } 

One thing to be aware of is that if you want to get the current object in the parent repeater than you have to obtain it with:

((RepeaterItem)Container.Parent.Parent).DataItem