Load controls in asp.net dynamically

1.Add placeholder to .aspx

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

2. add control loading code to codebehind :

string AlreadyLoaded=null;
private void loadControl(string ctr){
       if (!string.IsNullOrEmpty(ctr) && AlreadyLoaded!=ctr ) {
           Control ctrl = LoadControl(ctr);
           ctrl.ID="ctr1";
           PlaceHolderPanel.Controls.Clear();
           PlaceHolderPanel.Controls.Add(ctrl);
           ControlName = ctr;
           AlreadyLoaded=ctr;
       }

   }

protected void Page_Load(object sender, EventArgs e){
       loadControl("~/Controls/mycontrol.ascx");
}

There are limitations for loaded controls , one of them using onPreRender rather then Page_load:

// 1.call all functions in prerender only
protected override void OnPreRender(EventArgs e){
       SetFilterValues();
       Bind();
     base.OnPreRender(e);
}