MetaType class

6 min

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.

Create 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.

Code sample

// 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.

Create 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.

IMetaFieldInstaller interface 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.

IMetaObjectPropertyBinder interface 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.

[New in Commerce 14] You should register the custom meta-field installer and meta-object property binder in the appsettings.json Commerce section.

"Commerce":{      
    "MetaObjectTypeOptions": {
            "Types": [
              {
                "Name": "CustomType",
                "Installer": "",
                "Binder": ""
              }
            ]
          }
    }

Version 10-13

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>