c#从数据库结果填充树视图

我正在学习c#编程语言，正在为SAP business One制作工资应用程序附加组件。我以前从未使用过树视图，想知道如何从数据库中填充树项。我使用Visual Studio 2010和Microsoft SQL Server 2008。

我有一个父母和两个孩子，即

- Component                        ....Parent
      Earnings                     ....child
      Deductions                   ....child

我希望盈余子显示所有结果从一个U_PD_description字段，其中U_PD_type = "盈余"，即

- Component                        ....Parent
          Earnings                     ....child
              Housing Allowance
              Mobile Phone Allowance
              Mileage Allowance
          Deductions                   ....child

，对于演绎也是如此。我有下面的formload代码:

 private void frm_earn_deduct_setup_Load(object sender, EventArgs e)
        {
            // Get service instance
            var earnDeductMasterService = Program.Kernel.Get<IEarnDeductMasterService>();
            //Query database for all records that have earnings
            var earnings = from ed in earnDeductMasterService.GetAllEarnDeductMasters()
                           where ed.U_PD_type.Trim().Equals("Earnings".Trim(), StringComparison.CurrentCultureIgnoreCase)
                           select ed;
            if (earnings.Any(x => x != null))
            {
                //To populate subtree Earnings with U_PD_description results
                //.....some code here
            }
            else 
            {
                //Nothing to populate            
            }
            //.............................................................................
            //Query database for all records that have deductions
            var deductions = from ed in earnDeductMasterService.GetAllEarnDeductMasters()
                             where ed.U_PD_type.Trim().Equals("Deductions".Trim(), StringComparison.CurrentCultureIgnoreCase)
                             select ed;
            if (deductions.Any(x => x != null))
            {
                //To populate subtree Deductions with U_PD_description results
                //.....some code here
            }
            else
            {
                //Nothing to populate            
            }
            // Disable default items
            txt_amt_greater_than.Enabled = false; 
            bindingNavigatorDeleteItem.Enabled = false;
            // Call service instance
            earnDeductMasterBindingSource.DataSource = Program.Kernel.Get<IEarnDeductMasterService>().GetAllEarnDeductMasters().ToList();
        }

谁能告诉我一个例子，如何填充说收入子树在treeView1?

List<string> earnings = new List<string>() { "Housing Allowance", "Mobile Phone Allowance", "Mileage Allowance" };
List<string> deductions = new List<string>() { "Housing Ban", "Mobile Phone Ban", "Mileage Ban" };
treeView1.Nodes.Add("Component");//adding root node
treeView1.Nodes[0].Nodes.Add("Earnings");//adding earnings child node
treeView1.Nodes[0].Nodes.Add("Deductions");//adding deduction child node
//adding all earnings to "Earnings" node
foreach (string earning in earnings)
{
    treeView1.Nodes[0].Nodes[0].Nodes.Add(earning);
}
//adding all deductions to "Deductions" node
foreach (string deduction in deductions)
{
    treeView1.Nodes[0].Nodes[1].Nodes.Add(deduction);
}