| Platform SDK: Broadcast Architecture |
Because the Video control is an ActiveX control, it cannot exist outside of a container application. Examples of containers are Visual Basic forms, application windows, and HTML pages displayed by a Web browser.
When you use an ActiveX control such as the Video control in a Visual Basic application, the Visual Basic environment extends the control's functionality using an Extender object.
Using an Extender object, you can easily access and manipulate a control's interaction with its container. Extender also provides standard container functionality, such as sending an event when a user clicks on the control and setting whether the control is visible.
An Extender object is owned by the Visual Basic container, not the control. The Visual Basic container, however, exposes the properties, methods, and events of the Extender object as if they were part of the control. Some Extender properties are standard; others are specific to certain containers.
The following tables list and describe the Extender class properties, methods, and events provided by Visual Basic. The properties are as follows.
| Property | Description |
|---|---|
| Container | Read-only object that represents the container of a control, in this case of the Video control. The Container property returns or sets the container of the control on a Visual Basic form. |
| DragIcon | Icon to use when the control is dragged. |
| DragMode | Integer that specifies if the control can be dragged automatically, or if the application using the control must call the control's Drag method. |
| Enabled | Boolean value that specifies whether the control is enabled. |
| Height | Integer that specifies the height of the control in the container's scale units. |
| HelpContextID | Integer that specifies the Help context identifier to use when the F1 key is pressed and the control has the focus. |
| Index | Integer that specifies the position in a control array that one instance of the control occupies. |
| Left | Integer that specifies the position of the left edge of the control relative to the left edge of the container, specified in the container's scale units. |
| Name | String that contains the developer-defined name of the control. |
| Parent | Read-only object that represents the container of the control. The Parent property returns the form, object, or collection that contains the control. Use Parent to access the properties, methods, or events of the control's parent. |
| TabIndex | Integer that specifies the position of the control in the tab order of controls in the container. |
| TabStop | Boolean value that specifies if the cursor stops on the control when tabbing between controls. |
| Tag | String that contains an expression that stores any extra data needed for your application. |
| ToolTipText | String that contains the text to be displayed when the cursor hovers above the control for more than a second. |
| Top | Integer that specifies the position of the upper edge of the control relative to the upper edge of the container, specified in the container's scale units. |
| Visible | Boolean value that specifies whether the control is visible. |
| WhatThisHelpID | Context identifier to use when the What's This pop-up menu is used to provide information on the control. |
| Width | Width of the control in the container's scale units. |
Note The Container and Parent properties are similar. However, Parent is part of the standard set of Extender class properties, and Container is part of an additional set of properties that are not available for all containers.
The Extender class methods and additional extender methods provided by Visual Basic are listed following.
| Method | Description |
|---|---|
| Drag | Begins, ends, or cancels an operation in which the control is dragged. |
| Move | Moves the position of the control. |
| SetFocus | Sets the focus to the control. |
| ShowWhatsThis | Displays a selected Help topic using the What's This pop-up menu. |
| ZOrder | Places the control at the front or back of the z-order within the control's graphical level. |
The Extender class events and additional extender events provided by Visual Basic are listed following.
| Event | Description |
|---|---|
| DragDrop | Occurs when another control on the form is dropped on the control. |
| DragOver | Occurs when another control on the form is dragged over the control. |
| GotFocus | Occurs when the control gets focus |
| LostFocus | Occurs when the control loses focus. |