Databases Reference
In-Depth Information
table in the Northwind database, it can be changed by applying the
DisplayNameAttribute
to the entity class as shown here:
using System.ComponentModel;
[DisplayName(“Order Items”)]
partial class Order_Detail { }
Last, the
MetaTable
class has a set of three properties that determine how the actual data
retrieved from the database table needs to be displayed by the user interface elements
generated by Dynamic Data:
public virtual MetaColumn DisplayColumn { get; }
public virtual MetaColumn SortColumn { get;
public virtual bool SortDescending { get; }
The
DisplayColumn
property returns a
MetaColumn
object that represents the property
whose value would allow a user to identify a particular entity instance or table row. For
the Supplier entity class in the Northwind database scenario, this would normally be the
CompanyName
property; for the
Product
entity class, it would be the
ProductName
. The read-
only ForeignKey field template uses the
DisplayColumn
to provide text for a hyperlink it
generates, so that contact name of a Supplier is displayed on the Product details page.
The
SortColumn
property returns a
MetaColumn
that should be used to sort the items
retrieved from the database by default, and the
SortDescending
property indicates
whether the rows should be sorted in ascending or descending order of the
SortColumn
values. The ForeignKey_Edit field template uses these properties to sort the items in the
drop-down list it generates, making the Suppliers appear in the order of their
CompanyName:
using System.ComponentModel.DataAnnotations;
[DisplayColumn(“CompanyName”, “CompanyName”, false)]
partial class Supplier { }
By default,
MetaTable
uses a heuristic algorithm to guess the right display column. All
three of these properties,
DisplayColumn
,
SortColumn
, and
SortDescending
, can also be
specified explicitly by applying the
DisplayColumnAttribute
to the entity class as just
shown. Its constructor takes the name of the display column, the name of the sort
column, and a
Boolean
value that indicates whether default sorting should be performed
in descending order.
