MetaType class
The MetaType class represents the field type declarations string, HTML text, number, enums, file, and image. MetaType includes common types and you can extend it with UI-friendly types. For example, instead of using one type of string, Business Meta-Model has Short String, Long String, HTML, Email, Phone and number. You can create a new MetaType based on system type or create a custom one.
Business Foundation (BF) lets you use a number of different meta types for your .NET applications. You can use the included meta-types, or you can implement your own custom meta-type.
Default meta-types
Call the RegisteredTypes method of MetaClassManager class to get all registered meta-types. The following table shows ready-to-use BF meta-types.
Name | System Type | Represents |
---|---|---|
Guid |
Guid |
A globally unique identifier (GUID). |
DateTime |
DateTime |
An instant in time, typically expressed as a date and time of day. |
Date |
DateTime |
An instant in date. |
Integer |
Integer |
A 32-bit signed integer. |
Float |
Double |
A double-precision floating-point number. |
Currency |
Currency |
A currency number . |
CheckboxBoolean |
Boolean |
A Boolean value with checkbox. |
DropDownBoolean |
Boolean |
A Boolean value with drop-down. |
Text |
String |
Text of fixed length. Maximum length is 4096 chars. |
|
String |
An e-mail string. |
Url |
String |
A URL string. |
LongText |
String |
A long text. |
Html |
String |
An HTML string. |
File |
File |
A file (name, length, content type, stream). |
Image |
File |
An image file. |
IntegerPercent |
Integer |
A 32-bit signed integer percent. |
FloatPercent |
Double |
A double-precision floating-point percent. |
Duration |
Integer |
A 32-bit signed integer duration value. |
Creating a meta type based on system type
You can create a new meta-type based on system type. You can find a complete list of system types in the McDataType enumerators.
To create a meta-type, such as Geolocation based on the String system type, open the edit scope and add a new MetaFieldType object to the MetaClassManager.RegisteredTypes collection.
// Open Meta model edit scope
using (MetaClassManagerEditScope scope =
DataContext.Current.MetaModel.BeginEdit())
{
// Add a new meta type
MetaFieldType geoLocation = new MetaFieldType("Geolocation",
"Geolocation", McDataType.String);
DataContext.Current.MetaModel.RegisteredTypes.Add(geoLocation);
// Save Changes
scope.SaveChanges();
}
Or, add a new record to the mcmd_MetaFieldType table and restart the application.
*INSERT INTO mcmd_MetaFieldType ([Name], [FriendlyName], [McDataType]) VALUES ('Geolocation', 'Geolocation ', 6
After registration, you can add a geolocation field to the meta-class. Using the meta-type name, you can load a new geolocation view and edit the UI control.
Creating a custom meta type
When implementing a custom meta-type, you need to create the Meta-field installer and Meta-field property binder. When you create a meta-field, BF calls the meta-field installer to process meta-field into SQL columns. When you load an entity object, BF calls the meta-object property binder to convert values from an SQL column to a meta-field value.
To create a custom Meta-field installer, you create a class that implements the IMetaFieldInstaller interface, and implement the following methods.
Name | Description |
---|---|
AssignDataSource |
Create a new columns in the SQL database from meta-field |
AssignValidators |
Assign default validators |
UpdateDataSource |
Update SQL columns from updated meta-field |
UpdateValidators |
Update validators |
RemoveDataSource |
Remove columns from SQL database |
RemoveValidators |
Remove validators |
To create a custom Meta-object property binder, you create a class that implements the IMetaObjectPropertyBinder interface, and implement the following methods.
Name | Description |
---|---|
PreLoad |
Load value from SQL row and save to meta field property. |
PostLoad |
Fill properties by other. |
PreSave |
Save value to SQL row. |
PostSave |
Fill properties by other. |
Delete |
Clean up if meta field is removing. |
InitTableConfig |
Initialize additional SQL relations. |
You should register the custom meta-field installer and meta-object property binder in the mediachase.businessFoundation.data/metaObject/types section of the application config file.
<mediachase.businessFoundation.data>
<metaObject>
<types>
<add name="CustomType" installer="" binder="" />*
</types>
Last updated: Oct 12, 2015