Provides a callback mechanism that can create an instance of a service on demand.
Assembly: System (in System.dll)
'Declaration <ComVisibleAttribute(True)> _ <HostProtectionAttribute(SecurityAction.LinkDemand, SharedState := True)> _ Public Delegate Function ServiceCreatorCallback ( _ container As IServiceContainer, _ serviceType As Type _ ) As Object
- Type: System.ComponentModel.Design.IServiceContainer
The service container that requested the creation of the service.
- Type: System.Type
The type of service to create.
Return ValueType: System.Object
The service specified by serviceType, or Nothing if the service could not be created.
provides a mechanism to publish services that you can request to have created when needed, rather than the service being created immediately when the designer loads. You can use a callback function if the service is not essential and may not be used. A service published by using a does not use as many additional resources if it is not requested and created. To use a callback function to publish your service, pass a to the AddService method of an IServiceContainer.
The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: SharedState. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.
The following code example shows how to publish a service using a callback function.
' The following code shows how to publish a service using a callback function. ' Creates a service creator callback. Dim callback1 As New ServiceCreatorCallback _ (AddressOf myCallBackMethod) ' Adds the service using its type and the service creator. serviceContainer.AddService(GetType(myService), callback1)