Develop Reference

Linkbutton id inside a repeater

I have a linkbutton inside a repeater, and I need it to have an id in order to trigger a modal popup extender, but it is not working since the id is not correct due to the repeater.
<asp:Repeater ID="repeaterSessions" runat="server" OnItemCommand="repeaterSessions_OnItemCommand">
<ItemTemplate>
<p>
<%# ((Academia.SessionEN)Container.DataItem).Title %>
<asp:LinkButton ID="LinkButton1" runat="server" Text="Select" CommandArgument=<%#Eval("id") %>></asp:LinkButton>
</p>
</ItemTemplate>
</asp:Repeater>
After this we have the modal popup extender which triggers the linkbutton1:
<ajaxToolkit:ModalPopupExtender ID="LinkButton1_ModalPopupExtender" runat="server" Enabled="True" TargetControlID="LinkButton1" PopupControlID="Panel1">
I tried to add a new linkbutton1 outside the repeater with the id linkbutton1, and it works, but I'd like to know if it is possible to trigger this from inside the repeater.
Thanks everyone!
EDIT: It would also be a possibility to trigger the modal popup extender from the code behind function, but I don't know how to do it either.

asp.net web user control with loop

Totally new to webforms user controls, I am bit confused, on how to create a user control and fill some data on it.
for(int i = 0; i < Price.EpList.Count(); i++)
{
Price.EpList[i].Amount.ToString();
Price.EpList[i].Code.ToString();
Price.EpList[i].Desc.ToString();
Price.EpList[i].ID.ToString();
}
EpList is a list that contains info that i want to display in webpage on tabular format with checkboxes on each row.

Take a look at the Repeater Control. You don't have to loop through your list, you just bind the list to the repeater and define the html template you want for each repeated item.
http://www.w3schools.com/aspnet/aspnet_repeater.asp
EDIT: That article uses Visual Basic, so here's the C# translation:
Assuming this repeater:
<asp:Repeater runat="server" ID="uxEpList">
<ItemTemplate>
<%--Html goes here--%>
<%# Eval("Amount")%>
<%# Eval("Code")%>
<%# Eval("Desc")%>
<%# Eval("ID")%>
</ItemTemplate>
</asp:Repeater>
In code behind:
uxEpList.DataSource = Price.Eplist;
uxEpList.DataBind();
If you need to nest a repeater inside another one (using the Desc property from your comment) you can do it like this, by setting the DataSource property declaratively (note the single quotes):
<asp:Repeater runat="server" ID="uxEpList">
<ItemTemplate>
<asp:Repeater Datasource='<%# Eval("Desc")%>' runat="server">
<ItemTemplate>
//etc...

I am having an issue with ASP .NET user controls

I have an issue currently that I can't resolve. I have a user control called "Dashboard" which then has the following markup, containing several subcontrols.
<%# Control Language="C#" AutoEventWireup="true" CodeBehind="Dashboard.ascx.cs" Inherits="BlueSEQ.Controls.Dashboard.Dashboard" %>
<%# Register src="Administrator.ascx" tagname="Administrator" tagprefix="uc1" %>
<%# Register src="Provider.ascx" tagname="Provider" tagprefix="uc2" %>
<%# Register src="User.ascx" tagname="User" tagprefix="uc3" %>
<% if (isAdministrator)
{ %>
<uc1:Administrator ID="Administrator1" runat="server" />
<% }
else if (isProvider)
{ %>
<uc2:Provider ID="Provider1" runat="server" />
<% }
else
{ %>
<uc3:User ID="User1" runat="server" />
<% } %>
As you can see, I want it to display some controls or other controls depending on some conditions. However, all of these controls' "Load" event get triggered, even if they are not used.
How can I prevent this?

If you can help it, try to avoid having conditional logic in your markup. It could make the views somewhat more difficult to understand for designers (if you're working with designers) and more difficult to find and refactor this code in the future.
You should also take a look at ASP.NET MVC: Avoiding Tag Soup. Although it's ASP.NET MVC, it's still a good example of how adding logic to your views can quickly make them very difficult and unpleasant to maintain (initial example).
You could use the technique described here: How to: Add Controls to an ASP.NET Web Page Programmatically.
Your markup would look something like this.
<asp:PlaceHolder id="MyPlaceholder" />
and your codebehind would have something along the lines of
private void InitSection()
{
Control c;
if( isAdministrator )
c = Page.LoadControl("~\Administrator.ascx")
else if( isProvider )
c = Page.LoadControl("~\Provider.ascx")
else
c = Page.LoadControl("~\User.ascx");
MyPlaceholder.Controlls.Add(c);
}

The ideal way to do this is to set up asp.net role provider and use a LoginView control, something along the lines of the code below. LoginView only loads the appropriate content.
<asp:LoginView runat="server">
<AnonymousTemplate>
<uc1:User ID="User" runat="server" />
</AnonymousTemplate>
<RoleGroups>
<asp:RoleGroup Roles="Administrator">
<ContentTemplate>
<uc1:Administrator ID="Administrator1" runat="server" />
</ContentTemplate>
</asp:RoleGroup>
<asp:RoleGroup Roles="Provider">
<ContentTemplate>
<uc1:Provider ID="Provider" runat="server" />
</ContentTemplate>
</asp:RoleGroup>
</RoleGroups>
</asp:LoginView>

You have to Load the control on a specific condition instead, so try to set visible/invisible with the usercontrol, that's a much better approach
<% if (isAdministrator)
{ %>
Page.LoadControl(("~\Administrator1.ascx");
<% }

How about using a MultiView control?
MultiView on MSDN

CollapsiblePanelExtender inside a ListView

I am trying to have a collapsible panel inside of a listview item. In the item template, I have a panel, and a collapsible panel extender. In order to set the attributes TargetControlID, CollapseControlID, etc., I need the ClientIDs that are generated after databinding for each of the listview items. Does anyone know how I can set those attributes client-side?
I've tried various things along the lines of the following:
<ItemTemplate>
<asp:Panel ID="ManagingPanel" runat="server">
</asp:Panel>
<asp:CollapsiblePanelExtender runat="server" TargetControlID='<%="ManagingPanel.ClientID" %>' />
</ItemTemplate>
SOLUTION - Turns out you do not need to use the ClientID. The Extender will recognize that its target is inside the same listview item.
<asp:CollapsiblePanelExtender runat="server" TargetControlID="ManagingPanel" />

I have create a custom user control that includes the CollapsiblePanelExtender and every other think that I like to show, a complex html struct, and then I have include this control in the repeater.
The repeater pass the data that I need to render my custom control, and then the custom control render its self in every line of the repeater, and all is working fine.
something like
<asp:Repeater ID="myRepeater" runat="server">
<ItemTemplate>
<uc1:MyCustonControl ID="lPro" runat="server" data="<%#PassData%>" />
</ItemTemplate>
</asp:Repeater>

Turns out you do not need to use the ClientID. The Extender will recognize that its target is inside the same listview item.
<asp:CollapsiblePanelExtender runat="server" TargetControlID="ManagingPanel" />

Why can't I set the asp:Label Text property by calling a method in the aspx file?

Can somebody please explain this to me:
I have a label and I want to be able to set the Text property by calling a method in the aspx file. It works fine if I set the property in code behind, but I really want to set this property in the aspx file.
I have tried a couple of things, but what I expected to work was this:
<asp:Label ID="Label1" runat="server" Text=<%# GetMyText("LabelText") %> />
I get no errors when doing this, but my method is never called and the Text property is left empty.
Is it not possible to set property values to server side controls directly in the aspx without using resources or use hard coded values?
Update: My first try was:
<asp:Label ID="Label1" runat="server" Text=<%= GetMyText("LabelText") %> />
But that results in the following error:
Server tags cannot contain <% ... %> constructs.

The syntax =<%# ... %> is Data binding syntax used to bind values to control properties when the DataBind method is called.
You need to call DataBind - either Page.DataBind to bind all the controls on your page, or Label1.DataBind() to bind just the label. E.g. add the following to your Page_Load event handler:
if (!IsPostBack)
{
this.DataBind();
// ... or Label1.DataBind() if you only want to databind the label
}
Using Text='<%= GetMyText("LabelText") %>' as others have proposed won't work as you'll find out. This syntax is inherited from classic ASP. It can be used in some circumstances in ASP.NET for inserting dynamic values in static HTML, but can not be used for setting propeties of server controls.

The sysntax you are looking for is <%= %> the # is for data binding. So your code should read:
<asp:Label ID="Label1" runat="server" Text='<%= GetMyText("LabelText") %>' />
EDIT: This answere is incrrect
I am leaving this answer here because lots of people agreed with me that this is infact the correct answer, but it will not work. This line of code will produce the following HTML output:
<span id="Label1"><%= GetMyText("LabelText") %></span>

Try this:
<asp:Label ID="Label1" runat="server" Text='<%= GetMyText("LabelText") %>' />
Edit
Yep. I was wrong. #Joe was right.
However, THIS works (and I'm not sure what the difference is):
<asp:Label ID="Label1" runat="server"><%= GetMyText("LabelText") %></asp:Label>
CodeBehind:
protected string GetMyText(string input)
{
return "Hello " + HttpUtility.HtmlEncode(input);
}