ASP.NET AJAX UI

Re: Prevent update panel blink in parent when __doPostBack() is called

chetan.sarode — Mon, 06 Jul 2009 02:50:45 GMT

How UpdatePanel Controls Are Refreshed

The following list describes the property settings of the UpdatePanel control that determine when a panel's content is updated during partial-page rendering.

If the UpdateMode property is set to Always, the UpdatePanel control’s content is updated on every postback that originates from anywhere on the page. This includes asynchronous postbacks from controls that are inside other UpdatePanel controls, and postbacks from controls that are not inside UpdatePanel controls.
If the UpdateMode property is set to Conditional, the UpdatePanel control’s content is updated when one of the following is true:
- When the postback is caused by a trigger for that UpdatePanel control.
- When you explicitly call the UpdatePanel control's Update() method.
- When the UpdatePanel control is nested inside another UpdatePanel control and the parent panel is updated.
- When the ChildrenAsTriggers property is set to true and any child control of the UpdatePanel control causes a postback. Child controls of nested UpdatePanel controls do not cause an update to the outer UpdatePanel control unless they are explicitly defined as triggers for the parent panel.

If the ChildrenAsTriggers property is set to false and the UpdateMode property is set to Always, an exception is thrown. The ChildrenAsTriggers property is intended to be used only when the UpdateMode property is set to Conditional.

http://www.asp.net/ajax/documentation/live/overview/UpdatePanelOverview.aspx

Re: Prevent update panel blink in parent when __doPostBack() is called

Ibro — Sat, 04 Jul 2009 16:48:26 GMT

This blink is something I have come accross and I think is something caused by the Ajax,

Prevent update panel blink in parent when __doPostBack() is called

metaller — Fri, 03 Jul 2009 14:01:52 GMT

Hello there,

I've some problem with update panel (UP) in parent form blinking after __doPostBack() from child is called

When i do some action, like update som record in child (popup) window, I want to close the window, and force postback to parent.

Problem is, that after this, althought that page content is in UP, the page blinks...

this is the script I call from child

if (!Page.ClientScript.IsStartupScriptRegistered("CloseAjaxWithReload"))
{
    // Prepare the script to close the window
    StringBuilder script = new StringBuilder();
    script.Append("<script type=\"text/javascript\">");
    script.Append("window.open('', '_self', '');");
    script.Append("window.opener.__doPostBack('child');");
    script.Append("window.close();");
    script.Append("</script>");

    ScriptManager.RegisterStartupScript(this, this.GetType(), "CloseAjaxWithReload", script.ToString(), false);
}

Then in parent's page load, I catch, that postback was forced by child.

protected void Page_Load(object sender, EventArgs e)
{
    
    string eventTarget = (this.Request["__EVENTTARGET"] == null) ? string.Empty : this.Request["__EVENTTARGET"];

    if (!IsPostBack)
    {
        // Do nothing
    }
    else
    {
        if (eventTarget == "child")
        {
            // Call listview databind
            ReloadList();
        }  
    }
}

Whole content is in masterpage content and in UP.

<asp:Content ID="AccountListContent" ContentPlaceHolderID="cphContent" runat="server">

<asp:UpdatePanel ID="upMain" runat="server" UpdateMode="Conditional">
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID="cphContent" />
    </Triggers>    
    <ContentTemplate>
           //page content is here, also the listview
    </ContentTemplate>
</asp:UpdatePanel>
</asp:Content>

Everithing work's fine, except the page blink.

Any idea why is the page blinking???

Thx for any help, suggestion, whatever :)