Generated code - Custom properties
Preface
The designers of various objects as well as the project preferences give you the oppertunity to specify so called
custom properties.
Custom properties are name - value pairs (both strings) which are generated into the code (except for project custom properties) and add
both value to the XML comments added to the various methods and properties but also are available at runtime (Entities, Typed Views and Typed Lists).
This section describes in detail how to retrieve the custom properties for an entity, typed list or typed view or the custom properties
for the fields of these objects.
In generated code targeting .NET 1.x, the custom properties are stored in Hashtables. In generated code targeting .NET 2.0, the custom properties are
stored in Dictionary(Of string, string) objects (entity custom properties) and Dictionary(Of string, Dictionary(Of String, String)) for field custom
properties. The examples below are for .NET 1.x, however are easily migratable to .NET 2.0 code, by replacing the Hashtables with the proper types.
Entity/TypedList/TypedView custom properties
Entity, TypedList and TypedView custom properties are available in the form of a hashtable object. This object is created once per
type, in
a static (shared) constructor. This means that the custom properties are not eating a lot of memory in your application, nor do they increase the
size of your objects.
Each entity, typed list or typed view class has a static (shared) property called
CustomProperties. This static property can be used to
retrieve the hashtable with the name (which is the key in the hashtable) - value pairs for a particular class, at runtime. Below is an example
which illustrates the retrieval of the custom properties for the OrderEntity and which gets the value for the custom property 'Description' which
was added in the designer by the user.
// [C#]
Hashtable customProperties = CustomerEntity.CustomProperties;
string description = (string)customProperties["Description"];
' [VB.NET]
Dim customProperties As Hashtable = CustomerEntity.CustomProperties
Dim description As String = CType(customProperties("Description"), String)
Each entity/typed list/typed view instance also has a property called CustomPropertiesOfType. This property returns the hashtable of the type of the
instance. This is convenient so you can get the custom properties from an instance as well during runtime without having to determine the type.
// [C#]
// customer is an instance of CustomerEntity
Hashtable customProperties = customer.CustomPropertiesOfType;
string description = (string)customProperties["Description"];
' [VB.NET]
' customer is an instance of CustomerEntity
Dim customProperties As Hashtable = CustomerEntity.CustomPropertiesOfType
Dim description As String = CType(customProperties("Description"), String)
Entity/TypedList/TypedView field custom properties
Besides custom properties per entity/typed list/typed view, you can also define custom properties per entity field/typed list field/typed view field.
Per field these properties are stored in a hashtable object. These hashtable objects are stored per field name in the entity/typed list/typed view
class, similar to the class custom properties, also in a hashtable. The hashtable with the per-field hashtables is accessible through the
static property 'FieldsCustomProperties' or through the instance property 'FieldsCustomPropertiesOfType'.
Below is an example which retrieves a custom property called 'Description' from the custom properties
of a field called 'CustomerID' of the class CustomerEntity.
// [C#]
Hashtable fieldCustomProperties = (Hashtable)CustomerEntity.FieldsCustomProperties["CustomerID"];
string description = (string)fieldCustomProperties["Description"];
' [VB.NET]
Dim fieldCustomProperties As Hashtable = CType(CustomerEntity.FieldsCustomProperties("CustomerID"), Hashtable)
Dim description As String = CType(fieldCustomProperties("Description"), String)
For the runtime version, use the FieldCustomPropertiesOfType property on an instance, similar to the CustomPropertiesOfType property.
