Sorry I confused you with the reference to ListView2. I programed it as below. When I had the error I changed the name from ListView1 to ListView2 and changed back when that also errored. Today I deleted the "Default.aspx" in the PhotoAlbums folder and re-typed. I still get the same error. To execute I have open just the Default.aspx page and press Ctrl+F5, the execute window pops up with the error message.
Error
Server Error in '/' Application.
An item placeholder must be specified on ListView 'ListView1'. Specify an item placeholder by setting a control's ID property to "itemPlaceholder". The item placeholder control must also specify runat="server".
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.InvalidOperationException: An item placeholder must be specified on ListView 'ListView1'. Specify an item placeholder by setting a control's ID property to "itemPlaceholder". The item placeholder control must also specify runat="server".
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace:
[InvalidOperationException: An item placeholder must be specified on ListView 'ListView1'. Specify an item placeholder by setting a control's ID property to "itemPlaceholder". The item placeholder control must also specify runat="server".]
System.Web.UI.WebControls.ListView.GetPreparedCont ainerInfo(Control outerContainer, Boolean isItem, Int32& placeholderIndex) +503
System.Web.UI.WebControls.ListView.CreateItemsWith outGroups(ListViewPagedDataSource dataSource, Boolean dataBinding, InsertItemPosition insertPosition, ArrayList keyArray) +64
System.Web.UI.WebControls.ListView.CreateChildCont rols(IEnumerable dataSource, Boolean dataBinding) +1035
System.Web.UI.WebControls.ListView.PerformDataBind ing(IEnumerable data) +35
System.Web.UI.WebControls.DataBoundControl.OnDataS ourceViewSelectCallback(IEnumerable data) +123
System.Web.UI.DataSourceView.Select(DataSourceSele ctArguments arguments, DataSourceViewSelectCallback callback) +33
System.Web.UI.WebControls.DataBoundControl.Perform Select() +138
System.Web.UI.WebControls.ListView.PerformSelect() +102
System.Web.UI.WebControls.BaseDataBoundControl.Dat aBind() +30
System.Web.UI.WebControls.BaseDataBoundControl.Ens ureDataBound() +105
System.Web.UI.WebControls.ListView.CreateChildCont rols() +52
System.Web.UI.Control.EnsureChildControls() +83
System.Web.UI.Control.PreRenderRecursiveInternal() +42
System.Web.UI.Control.PreRenderRecursiveInternal() +155
System.Web.UI.Control.PreRenderRecursiveInternal() +155
System.Web.UI.Control.PreRenderRecursiveInternal() +155
System.Web.UI.Control.PreRenderRecursiveInternal() +155
System.Web.UI.Control.PreRenderRecursiveInternal() +155
System.Web.UI.Control.PreRenderRecursiveInternal() +155
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +974
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.18446
Here is the full markup:
<%@ Page Title="All Photo Albums" Language="C#" MasterPageFile="~/MasterPages/Frontend.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="PhotoAlbums_Default" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="cpMainContent" Runat="Server">
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:DropDownList ID="PhotoAlbumList" runat="server" AutoPostBack="True"
DataTextField="Name" DataValueField="Id"
OnSelectedIndexChanged="PhotoAlbumList_SelectedInd exChanged" SelectMethod="PhotoAlbumList_GetData">
</asp:DropDownList>
<asp:ListView ID="ListView1" runat="server" DataKeyNames="Id"
ItemType="Picture" SelectMethod="ListView1_GetData" >
<EmptyDataTemplate>
No pictures found for this photo album
</EmptyDataTemplate>
<ItemTemplate>
<li>
<asp:Image ID="Image1" runat="server"
ImageUrl='<%# Item.ImageUrl %>' ToolTip='<%# Item.ToolTip %>' />
<asp:Label ID="Description" runat="server" Text='<%# Item.Description %>' />
</li>
</ItemTemplate>
<LayoutTemplate>
<ul class="ItemContainer">
<li id="itemPlacholder" runat="server" />
</ul>
<div style="clear: both;">
<asp:DataPager ID="DataPager1" runat="server" PageSize="3">
<Fields>
<asp:NextPreviousPagerField ButtonType="Button"
ShowFirstPageButton="true" ShowLastPageButton="true" />
</Fields>
</asp:DataPager>
</div>
</LayoutTemplate>
</asp:ListView>
</ContentTemplate>
</asp:UpdatePanel>
</asp:Content>
Here is the code behind:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class PhotoAlbums_Default : BasePage
{
PlanetWroxEntities entities = new PlanetWroxEntities();
public IEnumerable<PhotoAlbum> PhotoAlbumList_GetData()
{
return from p in entities.PhotoAlbums
orderby p.Id
select p;
}
protected void Page_Load(object sender, EventArgs e)
{
}
protected void PhotoAlbumList_SelectedIndexChanged(object sender, EventArgs e)
{
ListView1.DataBind();
}
// The return type can be changed to IEnumerable, however to support
// paging and sorting, the following parameters must be added:
// int maximumRows
// int startRowIndex
// out int totalRowCount
// string sortByExpression
public IQueryable<Picture> ListView1_GetData()
{
int photoAlbumId = Convert.ToInt32(PhotoAlbumList.SelectedValue);
return from p in entities.Pictures
where p.PhotoAlbumId == photoAlbumId
orderby p.Id
select p;
}
}
Thank you for taking the time to review. I believe I followed your instructions, but if I missed something please point it out.
Most appreciated
Barrie
Chapter 14 error
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