Field Templates - ASP.NET Dynamic Data - page 96

LISTING 3.8 Continued
<add name=”NorthwindEntities”
providerName=”System.Data.EntityClient”
connectionString=”
metadata=res://*/Northwind.csdl|
res://*/Northwind.ssdl|
res://*/Northwind.msl;
provider=System.Data.SqlClient;
provider connection string=&quot;
data source=.\sqlexpress;
initial catalog=Northwind;
integrated security=True;
multipleactiveresultsets=True&quot;”/>
</connectionStrings>
</configuration>
Data Binding
Several of the built-in Dynamic Data field templates, including the DateTime and
DateTime_Edit templates, rely on data binding to display column value on the page.
<asp:TextBox ID=”textBox” runat=”server” Text='<%# FieldValueEditString %>' />
In addition, the field template controls themselves are data bound, and several properties
of the FieldTemplateUserControl base class rely on the data binding mechanics. These
properties can be used safely only from the DataBind method and will throw an
InvalidOperationException when used outside of the data binding context, such as
during a post-back:
. Row provides access to the entity instance the field template is bound to,
such as an Order object. In Read-only and Edit modes, it is an equivalent
of calling the Page.GetDataItem method. In Insert mode, this property returns a
CustomTypeDescriptor object that provides access to default field values extracted
by the page template from the page request URL (more on this in Chapter 6, “Page
Templates”).
. FieldValue returns value of the column property, such as Order.OrderDate . It is an
equivalent of calling DataBinder.Eval(Row, Column.Name) .
. FieldValueString converts the field value to a display string in Read-only mode,
using the formatting options specified in the data model or page markup. It is an
equivalent of calling FormattingOptions.FormatValue(FieldValue) .