Building Dynamic Forms - ASP.NET Dynamic Data - page 389

Markup of the TwoColumn entity template is shown in Listing 11.13. By comparing this
markup with the Default entity template back in Listing 11.4, you can see that it has an
additional HTML table with two cells, each of them containing a nested table and an
ASP.NET PlaceHolder control, where the dynamically instantiated controls will be added,
depending on their GroupName annotation.
LISTING 11.13 TwoColumn Entity Template (Mar kup)
<%@ Control Language=”C#” CodeBehind=”TwoColumn.ascx.cs”
Inherits=”WebApplication.DynamicData.EntityTemplates.TwoColumnEntityTemplate” %>
<asp:EntityTemplate runat=”server” ID=”entityTemplate”>
<ItemTemplate>
<tr>
<td class=”DDLightHeader”>
<unl:UnleashedLabel runat=”server” OnInit=”Label_Init” />
</td>
<td>
<unl:UnleashedControl runat=”server” OnInit=”DynamicControl_Init” />
</td>
</tr>
</ItemTemplate>
</asp:EntityTemplate>
<table>
<tr>
<td style=”vertical-align:top”>
<table class=” DDDetailsTable”>
<asp:PlaceHolder runat=”server” ID=”left” />
</table>
</td>
<td style=”vertical-align:top”>
<table class=” DDDetailsTable”>
<asp:PlaceHolder runat=”server” ID=”right” />
</table>
</td>
</tr>
</table>
Listing 11.14 shows the code-behind file of the TwoColumn entity template with the differ-
ences from the default entity template shown in bold font. The main difference from the
default entity template is located in the OnLoad method of the TwoColumnEntityTemplate .
Notice how instead of adding the dynamically created controls to the EntityTemplate
itself, it calls the FindGroupPlaceHolder method and adds them to the PlaceHolder
control it returns. In other words, the Default entity template uses the EntityTemplate
control as both a template to create the dynamic controls and a container to host them.
The TwoColumn template, however, uses the EntityTemplate control only as a template,
and the two PlaceHolder controls serve as containers for the generated controls.