How to create permanent controls in asp.net codebehind - asp.net

Question

I have to add some controls to my project master page in code behind,but I want to keep them even after post back.how can i do this? I've searched about it and I think that i have to use preinit ,but I don't Know how, and I don't know if master Page has preinit.
<form id="form1" runat="server">
<asp:ScriptManager ID="MainScriptmanager" runat="server" EnablePartialRendering="true" />
<asp:UpdatePanel ID="MasterContentUpdatePanel" runat="server" UpdateMode="conditional">
<ContentTemplate>
<asp:TabContainer ID="MainTabContainer" runat="server" ActiveTabIndex="1" TabStripPlacement="Bottom">
</asp:TabContainer>
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />
</ContentTemplate>
</asp:UpdatePanel>
</form>
protected void Button1_Click(object sender, EventArgs e)
{
tabCount = tabCount + 1;
AjaxControlToolkit.TabPanel tab = new AjaxControlToolkit.TabPanel();
tab.ID = "tab" + Convert.ToString(tabCount);
tab.HeaderText = "tab" + Convert.ToString(tabCount);
MainTabContainer.Tabs.Add(tab);
}

Answer 1

What keeps you from creating the controls and adding it to a, say, panel, in code behind? Create a panel in designer, name it, and create/add all the controls to in code behind wherever you need. Viewstate will preserve their contents between postbacks, you don't need to do anything extra.

Answer 2

You need to recreate the tabs on each postback.
E.g. you might store the count of tabs in ViewState.
Then on PostBack, you add the tabs e.g. in your Page_Load event handler:
var tabCount = ... get it from ViewState
for(int i=0; i<tabCount; i++)
{
AjaxControlToolkit.TabPanel tab = new AjaxControlToolkit.TabPanel();
tab.ID = "tab" + Convert.ToString(i+1);
tab.HeaderText = "tab" + Convert.ToString(i+1);
MainTabContainer.Tabs.Add(tab);
}