Try it out on page 505

fredfenk · April 10th, 2011, 01:13 AM

I am trying to do the try it out on page 505. I have checked over all of my code. compared the code to your source and I am continually getting the same error when I try to insert from the NEWPHOTOALBUM. The code that ASP.NET is complaining about is this:

Imports PlanetWroxModel

Partial Class _NewPhotoAlbum
Inherits BasePage

Protected Sub EntityDataSource1_Inserted(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.EntityDataSourceChangedE ventArgs) Handles EntityDataSource1.Inserted
Dim myPhotoAlbum As PhotoAlbum = CType(e.Entity, PhotoAlbum)
Response.Redirect(String.Format("ManagePhotoAlbum. aspx?PhotoAlbumId={0}",
myPhotoAlbum.Id.ToString()))
End Sub
End Class

ASP.NET keeps on pointing to the Response.redirect code. This is the error that I am getting.

NullReferenceException was unhandled by user code
Object reference not set to an instance of an object.

Troubleshooting tips:
use the "new" keyword to create an object instance.
Check to determine if the object is null before calling the method.
Get general help for this exception.

Any suggestions. I did not see any reference to this in the Erratta.

Fred Fenk

Imar · April 10th, 2011, 04:34 AM

Hi there,

Looks like the object isn't saved correctly (and is thus null). Maybe this helps?

Cannot redirect to ManagePhotoAlbum

Imar

fredfenk · April 13th, 2011, 08:31 AM

I blew away the last project and started over. I rebuilt the database and have gotten past my original problem. Now I am getting a different problem. Once I enter the new photoalbum on the NewPhotoAlbum asp page I am being taken to the next page ManagePhotoAlbum. But after I enter the information into the text boxes of the next page I get the following error in the database:
The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Picture_PhotoAlbum". I looked at the databases. In the PhotoAlbum database the information is inserting correctly. In the Picture database nothing is being input into the database. I have followed your instructions. Not sure what to do.

Sincerely,

Fred Fenk

Imar · April 13th, 2011, 11:45 AM

Hi Fred,

How are the tables related in the database? Take a look at the relation on the diagram in SQL Server.

Also, can you post the code for the new Album and tthe Picture pages?

Imar

fredfenk · April 13th, 2011, 01:01 PM

Ok, I got past that problem. Again I had to restart Chapter 14. I figured it had to do with the database and recreated it. So now everything works except for one thing. When I do the Try it out on page 515 and I try not to enter a .jpg url, I get an error in the ManagePhotoAlbum.aspx.vb code

Protected Sub ListView1_ItemInserting(sender As Object, e As System.Web.UI.WebControls.ListViewInsertEventArgs) Handles ListView1.ItemInserting
Dim FileUpload1 As FileUpload = CType(ListView1.InsertItem.FindControl("FileUpload 1"), FileUpload)
If Not FileUpload1.HasFile OrElse
Not FileUpload1.FileName.ToLower().EndsWith(".jpg") Then
Dim cusValImage As CustomValidator = CType(ListView1.InsertItem.FindControl("cusValImag e"), CustomValidator)
cusValImage.IsValid = False
e.Cancel = True
End If

End Sub

Mainly it does not like the "cusValImage.IsValid = False" is the complaint. The error that I am getting is:
NullReverenceException was unhandled by user code
Object reference not set to an instance of an object

Troubleshooting tips:
Use the "new" keyword to create an object instance.
Check to determine if the object is null before calling the method.
etc

Fred Fenk

Imar · April 13th, 2011, 01:16 PM

Hi Fred,

Can you show me the markup of that page? In particular, the section that defines the FileUpload and the CustomValidator controls?

Imar

fredfenk · April 13th, 2011, 02:16 PM

Here is all of the markup for the ManagePhotoAlbum.aspx that is in the maincontainer section.

<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="cpMainContent" Runat="Server">
<asp:ListView ID="ListView1" runat="server" DataKeyNames="Id"
DataSourceID="EntityDataSource1" InsertItemPosition="LastItem">
<InsertItemTemplate>
<li style="">
Description:
<asp:RequiredFieldValidator ID="reqDesc" runat="server" ControlToValidate="DescriptionTextBox" ErrorMessage="Enter a description." />
<asp:TextBox ID="DescriptionTextBox" runat="server"
Text='<%# Bind("Description") %>' />
 
ToolTip:
<asp:RequiredFieldValidator ID="reqToolTip" runat="server" ControlToValidate="ToolTipTextBox" ErrorMessage="Enter a tool tip." />
<asp:TextBox ID="ToolTipTextBox" runat="server" Text='<%# Bind("ToolTip") %>' />
 
<asp:FileUpload ID="FileUpload1" runat="server" />
<asp:CustomValidator ID="custValImage" runat="server" ErrorMessage="Select a valid .jpg file."/>
 
<asp:Button ID="InsertButton" runat="server" CommandName="Insert"
Text="Insert" />
<asp:Button ID="CancelButton" runat="server" CommandName="Cancel"
Text="Clear" CausesValidation="False" />
</li>
</InsertItemTemplate>
<itemtemplate>
<li style="">
Description:
<asp:Label ID="DescriptionLabel" runat="server"
Text='<%# Eval("Description") %>' />
 
ToolTip:
<asp:Label ID="ToolTipLabel" runat="server" Text='<%# Eval("ToolTip") %>' />
 
<asp:Image ID="ImageUrl" runat="server" ImageUrl='<%# Eval("ImageUrl") %>'/>
 
<asp:Button ID="DeleteButton" runat="server" CommandName="Delete"
Text="Delete" CausesValidation="False" />
</li>
</ItemTemplate>
<LayoutTemplate>
<ul class="ItemContainer">
<li runat="server" id="itemPlaceholder" />
</ul>
</LayoutTemplate>
</asp:ListView>
<asp:EntityDataSource ID="EntityDataSource1" runat="server"
ConnectionString="name=PlanetWroxEntities"
DefaultContainerName="PlanetWroxEntities" EnableDelete="True"
EnableFlattening="False" EnableInsert="True" EntitySetName="Pictures"
Where="it.PhotoAlbum.Id = @photoAlbumId">
<WhereParameters>
<asp:QueryStringParameter Name="PhotoAlbumId" QueryStringField="PhotoAlbumId"
Type="Int32" />
</WhereParameters>
</asp:EntityDataSource>
</asp:Content>

This also has the next try it out code incorporated.

Imar · April 13th, 2011, 03:16 PM

Here you have it:

Code:

 
<asp:CustomValidator ID="custValImage" runat="server" ErrorMessage="Select a valid .jpg file."/>

The control is called custValImage , yet in your code behind you try to find it (using FindControl) as "cusValImage".

Cheers.

Imar