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 implement a 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 check box.
DropDownBoolean	Boolean	A Boolean value with drop-down.
Text	String	Text of fixed length. Maximum length is 4096 chars.
EMail	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, 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.

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.

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MetaType class

Default meta-types

Creating a meta type based on system type

Creating a custom meta type