TCnBackgroundWorker Class
Initializes a new instance of the BackgroundWorker class.
CNClrLib.Control.Base.TClrBaseComponent
CNClrLib.Component.BackgroundWorker.TCnBackgroundWorker
type TCnBackgroundWorker = class(TClrBaseComponent) end;
The TCnBackgroundWorker type exposes the following members.
| Name | Description | |
|---|---|---|
 | Create(TComponent) | Initializes a new instance of the BackgroundWorker class. (Overrides TClrBaseComponent.Create(TComponent).) |
| Destroy | Frees the resources allocated with a BackgroundWorker instance. (Overrides TClrBaseComponent.Destroy.) |
| Name | Description | |
|---|---|---|
 | CancellationPending | Gets a value indicating whether the application has requested cancellation of a background operation. |
 | DefaultClrObject | Get the common language runtime object interface for this component. (Inherited from TClrBaseComponent.) |
| IsBusy | Gets a value indicating whether the BackgroundWorker is running an asynchronous operation. |
| WorkerReportsProgress | Gets or sets a value indicating whether the BackgroundWorker can report progress updates. |
| WorkerSupportsCancellation | Gets or sets a value indicating whether the BackgroundWorker supports asynchronous cancellation. |
| Name | Description | |
|---|---|---|
| CancelAsync | Requests cancellation of a pending background operation. |
| Dispose | Releases the resources used by the Component. (Inherited from TClrBaseComponent.) |
 | DoGetDefaultClrObject | Represents method |
| DoGetDotNetBaseComponent | Get the base component interface. (Overrides TClrBaseComponent.DoGetDotNetBaseComponent.) |
| GetClrObject | Represents method |
| RegisterEventCallBack(ClrWString,Pointer) | Add an event to the instance using the specified event name and function pointer which is the event handler. The RegisterEventCallBack method does not directly add the event handler to the event. A hooking mechanism is used such that if the event is fired, the hook event is also fired which in turn calls the function pointer. (Inherited from TClrBaseComponent.) |
| RegisterEventSource | Register the Delphi object which will raise the .Net event handler. (Inherited from TClrBaseComponent.) |
| ReportProgress(Integer) | Overloaded. Raises the OnProgressChanged event. |
| ReportProgress(Integer,Olevariant) | Overloaded. Raises the OnProgressChanged event. |
| RunWorkerAsync | Overloaded. Starts execution of a background operation. |
| RunWorkerAsync(Olevariant) | Overloaded. Starts execution of a background operation. |
| UnRegisterEventCallBack(ClrWString,Pointer) | Remove an event from the instance using the specified event name and function pointer which is the event handler. (Inherited from TClrBaseComponent.) |
| UnRegisterEventSource | Unregister the Delphi object which raised the .Net event handler. (Inherited from TClrBaseComponent.) |
| Name | Description | |
|---|---|---|
 | OnDoWork | Occurs when RunWorkerAsync() is called. |
| OnProgressChanged | Occurs when ReportProgress(Integer) is called. |
| OnRunWorkerCompleted | Occurs when the background operation has completed, has been canceled, or has raised an exception. |
The CnBackgroundWorker component allows you to run an operation on a
separate, dedicated thread. Time-consuming operations like downloads
and database transactions can cause your user interface (UI) to seem as
though it has stopped responding while they are running. When you want
a responsive UI and you are faced with long delays associated with such
operations, the CnBackgroundWorker component provides a convenient
solution.
To execute a time-consuming operation in the
background, create a CnBackgroundWorker and listen for events that
report the progress of your operation and signal when your operation is
finished. You can create the CnBackgroundWorker programmatically or you
can drag it onto your form from the Tool Palette. If you create the
CnBackgroundWorker in the Forms Designer, it will appear in the
Component Tray, and its properties will be displayed in the Object
Inspector.
To set up for a background operation, add an
event handler for the DoWork event. Call your time-consuming operation
in this event handler. To start the operation, call RunWorkerAsync . To
receive notifications of progress updates, handle the ProgressChanged
event. To receive a notification when the operation is completed,
handle the RunWorkerCompleted event.
 Note |
|---|
You must be careful not to manipulate any user-interface objects in your OnDoWork event handler. Instead, communicate to the user interface through the OnProgressChanged and OnRunWorkerCompleted events. |
See C:\Users\Public\Documents\CrystalNet Technologies\.Net VCL for Delphi Demo Folder after installation for examples of how to use this component.