Rendering an asp.net user control in a Panel

Question

I created this asp.net user control (just a sample for this stack overflow post)

HTML:

<%@ Control Language="vb" AutoEventWireup="false" CodeBehind="ucBTN.ascx.vb" Inherits="EBC_SAK_MVV_BTN.web.ucBTN" %>

<div>
    <asp:Button ID="btnLeft" runat="server" Width="200" Height="100" CssClass="btn btn-sq-lg btn-primary" Text="Button-Left" />
    <asp:Button ID="btnMiddle" runat="server" Width="200" Height="100" CssClass="btn btn-sq-lg btn-primary" Text="Button-Middle" />
    <asp:Button ID="btnRight" runat="server" Width="200" Height="100" CssClass="btn btn-sq-lg btn-primary" Text="Button-Right" />
</div>

Code behind:

Public Class ucBTN
    Inherits System.Web.UI.UserControl
    Public Property TextLeft As String
    Public Property TextMiddle As String
    Public Property TextRight As String
End Class

When I use this user control in a page it works (test.aspx):

<%@ Page Title="" Language="vb" AutoEventWireup="false" MasterPageFile="~/EBC.Master" CodeBehind="TEST.aspx.vb" Inherits="EBC_SAK_MVV_BTN.web.TEST" %>

<%@ Register Src="~/ucBTN.ascx" TagPrefix="uc1" TagName="ucBTN" %>
<uc1:ucBTN runat="server" ID="myBTN" />

But when I add a panel to my page and add my user control to this panel it keeps blank:

HTML:

<asp:Panel ID="Panel1" runat="server"></asp:Panel>

Code behind:

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim BTN As New ucBTN
BTN.TextLeft = "LEFT"
BTN.TextMiddle = "MIDDLE"
BTN.TextRight = "RIGHT"
Panel1.Controls.Add(BTN)
End Sub

I want to create dozends of these controls during runtime - how do I add them to my panel?

Answer 1

Use PlaceHolder instead of panel

in user control use:

  <asp:PlaceHolder ID="PlaceHolder1" runat="server"> 

in code behind use:

 PlaceHolder1.Controls.Add(BTN)