I am puzzled as to why the dynamically loaded content of an Active Tab disappears when I click on the Active Tab. But if I click on another Tab and go back to the previous tab the content appears.
<%@dotnet.itags.org.PageLanguage="C#"MasterPageFile="~/MasterPages/DeafaultMasterPage.master"AutoEventWireup="true"CodeFile="Default.aspx.cs"Inherits="_Default"Title="Default Page" %>
<asp:ContentID="Content2"ContentPlaceHolderID="cphBody"Runat="Server">
<scripttype="text/javascript"language="javascript">
function ActiveTabChanged(sender, e)
{
__doPostBack('<%= tcDefault.ClientID %>', sender.get_activeTab().get_headerText());
}
</script>
<ajaxToolkit:TabContainerID="tcDefault"runat="server"OnClientActiveTabChanged="ActiveTabChanged"OnActiveTabChanged="ActiveTabChangedServer">
<ajaxToolkit:TabPanelID="tab1"runat="server"HeaderText="Info"EnableViewState="true"><ContentTemplate>Dynamic content, load UserControl
</ContentTemplate></ajaxToolkit:TabPanel>
<ajaxToolkit:TabPanelID="tab2"runat="server"HeaderText="tab 2"EnableViewState="true"/></ajaxToolkit:TabContainer>
Code Behind
protected void Page_Load(object sender, EventArgs e) { ScriptManager sm = ScriptManager.GetCurrent(this.Page); sm.RegisterAsyncPostBackControl(tcDefault); } protected void ActiveTabChangedServer(object sender, EventArgs e) {// Initialize Tab TabContainer tc = (TabContainer)CommonUtility.FindControlRecursive(this,"tcDefault");if (tcDefault.ActiveTab == tab1) { LoadControl1(tc); }if (tcDefault.ActiveTab == tab2) {//Do something in code LoadControl2(tc); } }I noticed if I did the following;
protected void Page_Load(object sender, EventArgs e) { ReCreateTab(); } The content in the tab sticks, but then the content is displayed twice. I know it has something to do with the ViewState, but not sure how to debug and what to read, I am new at this .Net and Ajax.
Any help would be appreciate.
Hi,
This is a FAQ regarding dynamic controls in asp.net. Please refer to this:
1. Why do I have to recreate dynamic controls every time? /Why dynamic controls are disappeared on PostBack?
Whenever a request comes, a new instance of the page that isbeing requested is created to serve the request even it's a PostBack. Allcontrols on the page are reinitialized, and there state can be restored fromthe ViewState in a later phase.
The dynamic controls have to be recreated again and added tothe control hierarchy. Otherwise, they won't exist in the page.
Please be careful with when to create dynamic controls. Inorder to keep their state, they have to be created before the LoadViewStatephase. Page_Init as well as Page_Load methods are options available.
For more information about this topic, please refer to thisarticle:
Creating Dynamic Data Entry User Interfaces[http://msdn2.microsoft.com/en-us/library/aa479330.aspx ]
Hope this helps.
