Can I trigger an Update Panel from a Drop Down list in a User Control
Question
I have a user control in a master page with two drop down lists. When the user selects an item out of either ddl, I want to load a specific user control inside an update panel on the content page. I can't figure out how to get the user control to trigger the update panel. Any suggestions are very much appreciated.
Master
<%@ Register src="toolbar.ascx" tagname="toolbar" tagprefix="uc1" %>
<head id="Head1" runat="server">
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server">
</asp:ToolkitScriptManager>
</div>
<uc1:toolbar ID="toolbar1" runat="server" />
<asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server">
</asp:ContentPlaceHolder>
</form>
</body>
</html>
User Control
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="toolbar.ascx.cs" Inherits="Blah.toolbar" %>
<asp:DropDownList ID="ddlDesiredPage" runat="server" AutoPostBack="True"
EnableViewState="True"
onselectedindexchanged="goToSelectedPage">
<asp:ListItem Value="-">DDL 1</asp:ListItem>
</asp:DropDownList>
<asp:DropDownList ID="ddlDesiredPageSP" runat="server" AutoPostBack="True"
EnableViewState="True"
onselectedindexchanged="goToSelectedPage">
<asp:ListItem Value="-">DDL 2</asp:ListItem>
</asp:DropDownList>
Content Page
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<asp:UpdatePanel ID="UpdatePanel1" runat="server" onload="UpdatePanel1_Load">
<ContentTemplate>
<asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
</ContentTemplate>
<Triggers>
?????????????????????????????????
</Triggers>
</asp:UpdatePanel>
</asp:Content>
2 answers
solution1
2 ACCPTED 2010-03-23 19:53:31
If you want to update the panel via the User Control you've created, you could try setting the UpdatePanel's UpdateMode = Conditional . Then, in your User Control's click event (or whichever event), have something like this:
UpdatePanel mUpdatePanel = this.Page.Master.FindControl("upContent") as UpdatePanel;
if (mUpdatePanel != null)
{
mUpdatePanel.Update();
}
else
{
//update panel not found
}
UPDATE
Since you can't access your triggers declaratively, you could add them from the code-behind. On your content page, add something like this:
AsyncPostBackTrigger triggerUserControl = new AsyncPostBackTrigger();
DropDownList ucDDL = this.Page.Master.FindControl("ddlDesiredPage") as DropDownList;
triggerUserControl.ControlID = ucDDL.ID;
triggerUserControl.EventName = "Click";
UpdatePanel1.Triggers.Add(triggerUserControl);
Do the same for the other DropDownList. I haven't tried this, but it seems reasonable.
solution2
1 2010-03-23 20:19:55
Try adding a postback trigger to your UpdatePanel:
<Triggers>
<asp:PostBackTrigger ControlID="ddl..." />
</Triggers>
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