Forms Data Controls :: 2 Dropdown List / "Displaying A Dropdown List Of Categories With A --None -- Option?

I am stuck at this point "Displaying a dropdown list of Categories with a --None -- Option. I want the gridview control to display 2 dropdown list one in read-only mode and the other in edit mode. When a record is in read-only mode, the dropdownlist's enabled property will be set to false."When it's on a read-only mode, it doesn't display the selected Category. it shows but the "No Category". When i click on edit to edit or change category, it doesn't display the selected category.

The example is given below( I am reading the book Sams Teach yourself ASP.NET 2.0 by Scott Mitchell. page 628)

<asp:Label ID="UserIdValue" runat="server" Visible="False"></asp:Label>
<asp:SqlDataSource ID="picturesDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:ConnectionString %>"
SelectCommand="SELECT * FROM [Pictures] WHERE ([UserId] = @UserId) ORDER BY [UploadedOn] DESC"
DeleteCommand="DELETE FROM [Pictures] WHERE [PictureID] = @PictureID"
InsertCommand="INSERT INTO [Pictures] ([UserId], [CategoryID], [Title], [Description], [UploadedOn]) VALUES (@UserId, @CategoryID, @Title, @Description, @UploadedOn)"
UpdateCommand="UPDATE [Pictures] SET [UserId] = @UserId, [CategoryID] = @CategoryID, [Title] = @Title, [Description] = @Description, [UploadedOn] = @UploadedOn WHERE [PictureID] = @PictureID">
<DeleteParameters>
<asp:Parameter Name="PictureID" Type="Int32" />
</DeleteParameters>
<InsertParameters>
<asp:Parameter Name="UserId" />
<asp:Parameter Name="CategoryID" Type="Int32" />
<asp:Parameter Name="Title" Type="String" />
<asp:Parameter Name="Description" Type="String" />
<asp:Parameter Name="UploadedOn" Type="DateTime" />
</InsertParameters>
<SelectParameters>
<asp:ControlParameter ControlID="UserIdValue" Name="UserId" PropertyName="Text"/>
</SelectParameters>
<UpdateParameters>
<asp:Parameter Name="UserId"/>
<asp:Parameter Name="CategoryID" Type="Int32" />
<asp:Parameter Name="Title" Type="String" />
<asp:Parameter Name="Description" Type="String" />
<asp:Parameter Name="UploadedOn" Type="DateTime" />
<asp:Parameter Name="PictureID" Type="Int32" />
</UpdateParameters>
</asp:SqlDataSource>
<br />
<asp:SqlDataSource ID="categoriesDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:ConnectionString %>"
SelectCommand="SELECT [CategoryID], [Name] FROM [Categories] WHERE ([UserId] = @UserId)">
<SelectParameters>
<asp:ControlParameter ControlID="UserIdValue" Name="UserId" PropertyName="Text" />
</SelectParameters>
</asp:SqlDataSource>
<br />
<asp:SqlDataSource ID="maxPictureIDDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:ConnectionString %>" SelectCommand="SELECT MAX(PictureID)
FROM Pictures
WHERE UserId = @UserId">
<SelectParameters>
<asp:ControlParameter ControlID="UserIdValue" Name="UserId"
PropertyName="Text" />
</SelectParameters>
</asp:SqlDataSource>
<br />
<asp:Label ID="cannotUploadImageMessage" runat="server"
Text="The photo could not be added to your album either because you did not specify a file to upload or the file specified was not a JPEG image with the file extension .JPG"></asp:Label>
<br />
<asp:DetailsView ID="dvPictureInsert" runat="server"
DataSourceID="PicturesDataSource" Height="50px" Width="125px"
AutoGenerateRows="False" CellPadding="4" DataKeyNames="PictureID"
DefaultMode="Insert" ForeColor="#333333" GridLines="None">
<AlternatingRowStyle BackColor="White" />
<CommandRowStyle BackColor="#D1DDF1" Font-Bold="True" />
<EditRowStyle BackColor="#2461BF" />
<FieldHeaderStyle BackColor="#DEE8F5" Font-Bold="True" />
<Fields>
<asp:TemplateField HeaderText="Picture">
<InsertItemTemplate>
<asp:FileUpload ID="imageUpload" runat="server" />
<asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server"
ControlToValidate="imageUpload" Display="Dynamic"
ErrorMessage="There was no file selected" ValidationGroup="PictureAdd"></asp:RequiredFieldValidator>
</InsertItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Category" SortExpression="CategoryID">
<EditItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("CategoryID") %>'></asp:TextBox>
</EditItemTemplate>
<InsertItemTemplate>
<asp:DropDownList ID="pictureCategory" DataSourceID="categoriesDataSource"
runat="server" DataTextField="Name" DataValueField="CategoryID"
SelectedValue='<%# Bind("CategoryID") %>'
Visible='<%# Bind("CategoryID") %>' AppendDataBoundItems="True">
<asp:ListItem Selected="True" Value="">-- Select Category --</asp:ListItem>
</asp:DropDownList>
</InsertItemTemplate>
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%# Bind("CategoryID") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Title" SortExpression="Title">
<EditItemTemplate>
<asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("Title") %>'></asp:TextBox>
</EditItemTemplate>
<InsertItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("Title") %>'></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"
ControlToValidate="TextBox1" Display="Dynamic"
ErrorMessage="you must provide a name for the title"
ValidationGroup="PictureAdd"></asp:RequiredFieldValidator>
</InsertItemTemplate>
<ItemTemplate>
<asp:Label ID="Label2" runat="server" Text='<%# Bind("Title") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Description" SortExpression="Description">
<EditItemTemplate>
<asp:TextBox ID="TextBox3" runat="server" Text='<%# Bind("Description") %>'></asp:TextBox>
</EditItemTemplate>
<InsertItemTemplate>
<asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("Description") %>'