Change Event (ActiveX Controls)
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Change Event (ActiveX Controls)

Visual Studio .NET 2003

Indicates the contents of a control or a property value have changed. How and when this event occurs varies with the control.

Syntax

Private Sub object_Change([index As Integer])

The Change event syntax has these parts:

Part Description
object An object expression that evaluates to an object in the Applies To list.
index An integer that uniquely identifies a control if it's in a control array.

Remarks

The Change event procedure can synchronize or coordinate data display among controls. For example, you can use a scroll bar's Change event procedure to update the scroll bar's Value property setting in a TextBox control. Or you can use a Change event procedure to display data and formulas in a work area and results in another area.

Note   A Change event procedure can sometimes cause a cascading event. This occurs when the control's Change event alters the control's contents, for example, by setting a property in code that determines the control's value, such as the Text property setting for a TextBox control.

To prevent a cascading event:

  • If possible, avoid writing a Change event procedure for a control that alters that control's contents. If you do write such a procedure, be sure to set a flag that prevents further changes while the current change is in progress.
  • Avoid creating two or more controls whose Change event procedures affect each other, for example, two TextBox controls that update each other during their Change events.
  • Avoid using a MsgBox function or statement in this event for HScrollBar and VScrollBar controls.

See Also

Applies To: Masked Edit Control

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