Wednesday, March 28, 2012

LinkButton Trigger inside a repeater

 I have been searching all over for an answer but have yet to find anything. 

I have a repeater that I use to display a letter paging system. It looks something like this

<asp:Repeater ID="rpt_Letters" runat="server"> <ItemTemplate> <asp:LinkButton ID="lbtn_Letter" CausesValidation="false" CommandName="Filter" CommandArgument='<%# Eval("Letter") %>' runat="server" style="padding-left:7px; padding-top: 10px;" ToolTip='<%# Eval("Letter") %>'><%# Eval("Letter") %></asp:LinkButton> </ItemTemplate> </asp:Repeater>

Once a letter is clicked I want to update the information in a GridView.

I have the GridView in an update panel, but I can't find away to set my Letter Paging as a trigger.


Hi,

an approach could be wrapping the repeater with an UpdatePanel with UpdateMode="Conditional" and ChildrenAsTriggers="false". This won't make the panel update when a LinkButton is clicked, but will trigger an asynchronous postback where you can update the panel that contains the GridView. Check this basic example:

<%@. Page Language="C#" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><script runat="server"> protected void Page_Load(object sender, EventArgs e) { if (!Page.IsPostBack) { repTriggers.DataSource = new int[3] { 0, 1, 2 }; repTriggers.DataBind(); } } protected void repTriggers_ItemCommand(object sender, RepeaterCommandEventArgs e) { if (e.CommandName == "trigger") { LinkButton btn = e.CommandSource as LinkButton; if (btn != null) { lblUpdate.Text = "Update triggered by " + btn.ID + e.Item.ItemIndex.ToString(); } UpdatePanel2.Update(); } }</script><html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server"> <title>Untitled Page</title></head><body> <form id="form1" runat="server"> <asp:ScriptManager ID="TheScriptManager" runat="server"></asp:ScriptManager> <asp:UpdatePanel ID="UpdatePanel1" runat="server" ChildrenAsTriggers="false" UpdateMode="conditional"> <ContentTemplate> <asp:Repeater ID="repTriggers" runat="server" OnItemCommand="repTriggers_ItemCommand"> <ItemTemplate> <asp:LinkButton ID="lnkTrigger" runat="server" Text="Trigger" CommandName="trigger"></asp:LinkButton> </ItemTemplate> </asp:Repeater> </ContentTemplate> </asp:UpdatePanel> <asp:UpdatePanel ID="UpdatePanel2" runat="server" UpdateMode="conditional"> <ContentTemplate> <asp:Label ID="lblUpdate" runat="server"></asp:Label> </ContentTemplate> </asp:UpdatePanel> </form></body></html>

Good suggestion, Garbin, but I think I have an even easier way. You can simply add your Repeater as a trigger for your UpdatePanel. Here's my version, with comments indicating where it differs from Garbin's:

<%@. Page Language="C#" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><script runat="server"> protected void Page_Load(object sender, EventArgs e) { if (!Page.IsPostBack) { repTriggers.DataSource = new int[3] { 0, 1, 2 }; repTriggers.DataBind(); } } protected void repTriggers_ItemCommand(object sender, RepeaterCommandEventArgs e) { if (e.CommandName == "trigger") { LinkButton btn = e.CommandSource as LinkButton; if (btn != null) { lblUpdate.Text = "Update triggered by " + btn.ID + e.Item.ItemIndex.ToString(); } // [Steve] removed UpdatePanel2.Update() } }</script><html xmlns="http://www.w3.org/1999/xhtml" ><head id="Head1" runat="server"> <title>Untitled Page</title></head><body> <form id="form1" runat="server"> <asp:ScriptManager ID="TheScriptManager" runat="server"></asp:ScriptManager><%-- [Steve] removed UpdatePanel1 --%> <asp:Repeater ID="repTriggers" runat="server" OnItemCommand="repTriggers_ItemCommand"> <ItemTemplate> <asp:LinkButton ID="lnkTrigger" runat="server" Text="Trigger" CommandName="trigger"></asp:LinkButton> </ItemTemplate> </asp:Repeater> <asp:UpdatePanel ID="UpdatePanel2" runat="server" UpdateMode="conditional"><%-- [Steve] added repTriggers as an AsyncPostBackTrigger --%> <Triggers> <asp:AsyncPostBackTrigger ControlID="repTriggers" /> </Triggers> <ContentTemplate> <asp:Label ID="lblUpdate" runat="server"></asp:Label> </ContentTemplate> </asp:UpdatePanel> </form></body></html>

Hi,

yes, definitely :)


Thank you!

That was too easy! I can't believe I never tried that.Embarrassed

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