MSVidWebDVD.UOPValid Method

Note  This topic applies to Windows XP Service Pack 1 or later.

The UOPValid method retrieves a value that indicates whether the specified user operation (UOP) is currently valid.

VidWebDVD.UOPValid(
   lUOP As Long
) As Boolean

Parameters

• lUOP
  Specifies the user operation (UOP) as a Long. Values can include the following.

  Value	Description
  0	PlayTitle, PlayAtTime, and PlayAtTimeInTitle
  1	PlayChapter
  2	PlayTitle
  3	Stop (not enforced on the MSVidCtl object)
  4	ReturnFromSubmenu
  5	PlayChapter
  6	PlayPrevChapter, ReplayChapter
  7	PlayNextChapter
  8	Forward play allowed.
  9	Backward play allowed.
  10	ShowMenu with a parameter value of 2 (DVD_MENU_Title).
  11	ShowMenu with a parameter value of 3 (DVD_MENU_Root).
  12	ShowMenu with a parameter value of 4 (DVD_MENU_Subpicture).
  13	ShowMenu with a parameter value of 5 (DVD_MENU_Audio).
  14	ShowMenu with a parameter value of 6 (DVD_MENU_Angle).
  15	ShowMenu with a parameter value of 7 (DVD_MENU_Chapter).
  16	Resume
  17	SelectLeftButton, SelectRightButton, SelectUpperButton, and SelectLowerButton
  18	StillOff
  19	Pause (not enforced on the MSVidCtl object)
  20	CurrentAudioStream
  21	CurrentSubpictureStream
  22	CurrentAngle, SelectParentalLevel
  23	KaraokeAudioPresentationMode
  24	Select video mode preference.

Return Value

Returns a Boolean indicating whether the specified operation is permitted.

Error Codes

If the property fails, Err.Number may be set to one of the following values.

Remarks

DVD authors can encode the disc to enable or disable certain commands by the user. These user operations (UOP) generally handle disc navigation. Attempting to access a property or method that is not currently allowed or valid will cause your application to raise an error. UOPValid allows you to determine if you can access a method or property to avoid such errors.

In addition to avoiding run-time errors, UOPValid allows you to visibly disable controls for prohibited actions on the user interface.

Certain methods—Stop, Pause, and Run—apply to both the MSVidWebDVD object and the MSVidCtl object. These methods should be run from the MSVidCtl object, or your application will raise an error. Disc permissions cannot prevent the MSVidCtl object from implementing these methods even when the UOPValid method returns false. However, an application designer may choose to disable user controls for these methods when the UOP value is false.

Add a reference to MS Video Control 10 Type Library and Microsoft Tuner 10 Type Library.

Examples

' Check if forward or reverse play is allowed before changing playback rate.
dRate = txtRate.Text
If oVidWebDVD.UOPValid(&H80) And dRate > 0 Then  ' Handle forward.
   oVidWebDVD.Rate = dRate
ElseIf oVidWebDVD.UOPValid(&H100) And dRate < 0 Then   ' Handle reverse.
   oVidWebDVD.Rate = dRate
End If

Requirements

See Also

MSVidWebDVD Object

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Build date: 12/4/2008