Возможно, как-то так?
Default.aspx
<%@ Page Language="C#" %>
<script runat="server">
protected override void CreateChildControls()
{
base.CreateChildControls();
LoadUserControl();
}
private void LoadUserControl()
{
ph.Controls.Clear();
Control c = LoadControl("~/WebUserControl.ascx");
c.ID = "foo";
ph.Controls.Add(c);
}
</script>
<html>
<body>
<form id="form1" runat="server">
<div>
<asp:PlaceHolder ID="ph" runat="server" />
</div>
<asp:Button runat="server" />
</form>
</body>
</html>
WebUserControl.ascx
<%@ Control Language="C#" %>
<%@ Import Namespace="System.Data" %>
<script runat="server">
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
if (!IsPostBack)
{
DataTable dt = GetRawDataTable();
dt.Rows.Add(dt.NewRow());
rpt.DataSource = dt;
rpt.DataBind();
}
}
private static DataTable GetRawDataTable()
{
DataTable dt = new DataTable();
dt.Columns.Add(new DataColumn("product", typeof(string)));
dt.Columns.Add(new DataColumn("checked", typeof(bool), "false"));
return dt;
}
protected void OnBtnAddClicked(object sender, EventArgs e)
{
DataTable dt = GetRawDataTable();
foreach (RepeaterItem ri in rpt.Items)
{
TransferFromPage(ri, dt);
}
dt.Rows.Add(dt.NewRow());
rpt.DataSource = dt;
rpt.DataBind();
}
private static void TransferFromPage(RepeaterItem ri, DataTable dt)
{
DataRow row = dt.NewRow();
row["product"] = ((TextBox)ri.FindControl("txtProduct")).Text;
row["checked"] = ((CheckBox) ri.FindControl("chk")).Checked;
dt.Rows.Add(row);
}
protected void OnRptItemCmd(object sender, RepeaterCommandEventArgs ea)
{
switch (ea.CommandName)
{
case "RemoveRow":
DataTable dt = GetRawDataTable();
foreach (RepeaterItem ri in rpt.Items)
{
if (ri.ItemIndex == ea.Item.ItemIndex) continue;
TransferFromPage(ri, dt);
}
rpt.DataSource = dt;
rpt.DataBind();
break;
}
}
</script>
<div>
<table>
<asp:Repeater ID="rpt" runat="server" OnItemCommand="OnRptItemCmd">
<ItemTemplate>
<tr>
<td>
<asp:TextBox ID="txtProduct" runat="server" Text='<%# Eval("product") %>' />
<asp:CheckBox ID="chk" runat="server" Checked='<%# Eval("checked") %>' />
<asp:Button ID="btnRemove" runat="server" Text="-" CommandName="RemoveRow" />
</td>
</tr>
</ItemTemplate>
<FooterTemplate>
<tr>
<td>
<asp:Button ID="btnAdd" runat="server" Text="+" OnClick="OnBtnAddClicked" />
</td>
</tr>
</FooterTemplate>
</asp:Repeater>
</table>
</div>