private void rptMonthSummary_ItemDataBound(object sender, System.Web.UI.WebControls.RepeaterItemEventArgs e)
{
  ListItemType lt = e.Item.ItemType;
  if(lt == ListItemType.Item || lt == ListItemType.AlternatingItem)
  {
    DataRowView dv = e.Item.DataItem as DataRowView;
    if(dv != null)
    {
      Repeater nestedRepeater = e.Item.FindControl("rptDailySummary") as Repeater;
      if (nestedRepeater != null)
      {
        nestedRepeater.DataSource = dv.CreateChildView("yearMonth");
        nestedRepeater.DataBind();
      }
    }
  }
}
 
 
//here's a full code-behind that uses a strongly typed list of results to filter:
 
		public List<ProductWithType> ProductList = new List<ProductWithType>();
 
        protected void Page_Load(object sender, EventArgs e)
        {
			GetProducts();
        }
 
		private void GetProducts()
		{
			using (FTJEntities context = new FTJEntities())
			{
				ProductList = (from p in context.Products
							   orderby p.ProductType.Name, p.Name
							select new ProductWithType() 
							{
								ProductID = p.ProductID,
								ProductTypeID = p.ProductTypeID,
								Name = p.Name,
								Type = p.ProductType.Name,
								ShortDescription = p.ShortDescription
							}).ToList<ProductWithType>();
				rptProductTypes.DataSource = ProductList;
				rptProductTypes.DataBind();
			}
		}
 
		public void rptProductTypes_ItemDataBound(object sender, System.Web.UI.WebControls.RepeaterItemEventArgs e)
		{
			ListItemType lt = e.Item.ItemType;
 
			if (!(lt == ListItemType.Item || lt == ListItemType.AlternatingItem)) return; //only interested in the item/alternatingitem databind calls to this method, not the header, footer, etc.
 
			ProductWithType product = e.Item.DataItem as ProductWithType; //get the current row being databound
 
			Repeater rptProducts = e.Item.FindControl("rptProducts") as Repeater; //get the nested control
			rptProducts.DataSource = from p in ProductList where p.ProductTypeID == product.ProductTypeID select p;
			rptProducts.DataBind();
		}
    }
 
	/// <summary>
	/// Used so result set above can be strongly typed.
	/// </summary>
	public class ProductWithType
	{
		public int ProductID { get; set; }
		public int ProductTypeID { get; set; }
		public string Name { get; set; }
		public string Type { get; set; }
		public string ShortDescription { get; set; }
	}