PointIterator Methods
The PointIterator object contains the following methods:
Initialize
The Initialize method initializes a PointIterator object.
Syntax
Initialize(VhsSiteService As String, OrderByPointIdLong As Long, Unused As Long) As Long
Parameters
| Parameter | Required | Description |
|---|---|---|
|
VhsSiteService |
Yes |
The site and service name of the VHS point tag, in "site.service" format. |
|
OrderByPointIdLong |
Yes |
Set to any nonzero number to sort the points alphabetically by Long ID, or zero to leave them unsorted. |
|
Unused |
Yes |
This can be any Long number, but it doesn’t affect anything. |
Remarks
This function initializes the point iterator object to the start or end of the point list, depending on the value of Backward. The return value is based on whether the initialization was successful or not (1 = Success; 0 = Failure). When initialized, the iterator cursor moves to the first point by default.
Example
The following subroutine demonstrates the use of the Initialize, MoveFirst, and GetForward methods of the PointIterator object. It displays a list of all points in a VHS.
Sub ShowAllPoints (vhsService)
Dim vhsPointIter, vhsHistoryIter, tag, stat
lstPoints.ResetContent
Set vhsPointIter = CreateObject("CxVhsLib.PointIterator")
Set tag = CreateObject("CxVhsLib.HistoryTagStringEx")
Set stat = CreateObject("CxVhsLib.HistoryStats")
'Initialize point iterator with Short Point ID, going forward
vhsPointIter.Initialize vhsService, 0, 0
vhsPointIter.MoveFirst
'Show all points in a list box
While (vhsPointIter.GetForward(tag, stat))
lstPoints.AddString(tag.TagString)
Wend
End Sub
GetBackward
The GetBackward method retrieves information about the previous point in the iteration list.
Syntax
GetBackward(pTag As Variant, pStats As Variant) As Long
Parameters
| Parameter | Required | Description | Variant |
|---|---|---|---|
|
pTag |
Yes |
Output. Returns the site, service, Short Point ID, Long Point ID, and tag string for a point in the VHS. |
|
|
pStats |
Yes |
Output. Returns the entry count, timestamp start, timestamp end, and expiration days for a point in the VHS. |
Remarks
The GetBackward function retrieves information for a point and moves the cursor backward. The return value is 1 while there are still points in the list. When the end of the list is reached, 0 is returned.
Example
The following subroutine demonstrates the use of the Initialize, MoveLast, and GetBackward methods of the PointIterator object. It displays a list of the last thirty points in a VHS.
Sub ShowLastThirty (vhsService)
Dim vhsPointIter, vhsHistoryIter, tag, stat, counter
lstPoints.ResetContent
counter = 0
Set vhsPointIter = CreateObject("CxVhsLib.PointIterator")
Set tag = CreateObject("CxVhsLib.HistoryTagStringEx")
Set stat = CreateObject("CxVhsLib.HistoryStats")
'Initialize point iterator with Long Point ID, going backward
vhsPointIter.Initialize vhsService, 1, 1
vhsPointIter.MoveLast
'Show all points in a list box
While ((vhsPointIter.GetBackward(tag, stat)) And (counter < 30))
lstPoints.AddString(tag.TagString)
counter = counter + 1;
Wend
End Sub
GetForward
The GetForward method retrieves information about the next point in the iteration list.
Syntax
GetForward(pTag As Variant, pStats As Variant) As Long
Parameters
| Parameter | Required | Description | Variant |
|---|---|---|---|
|
pTag |
Yes |
Output. Returns the site, service, Short Point ID, Long Point ID, and tag string for a point in the VHS. |
|
|
pStats |
Yes |
Output. Returns the entry count, timestamp start, timestamp end, and expiration days for a point in the VHS. |
Remarks
The GetForward function retrieves information for the next point and moves the cursor forward. The return value is 1 while there are still points in the list. When the end of the list is reached, 0 is returned.
Example
The following subroutine demonstrates the use of the Initialize, MoveFirst, and GetForward methods of the PointIterator object. It displays a list of all points in a VHS.
Sub ShowAllPoints (vhsService)
Dim vhsPointIter, vhsHistoryIter, tag, stat
lstPoints.ResetContent
Set vhsPointIter = CreateObject("CxVhsLib.PointIterator")
Set tag = CreateObject("CxVhsLib.HistoryTagStringEx")
Set stat = CreateObject("CxVhsLib.HistoryStats")
'Initialize point iterator with Short Point ID, going forward
vhsPointIter.Initialize vhsService, 0, 0
vhsPointIter.MoveFirst
'Show all points in a list box
While (vhsPointIter.GetForward(tag, stat))
lstPoints.AddString(tag.TagString)
Wend
End Sub
MoveAfter
The MoveAfter method moves the cursor after the given point.
Syntax
MoveAfter(pTag As Variant) As Long
Parameters
| Parameter | Required | Description | Variant |
|---|---|---|---|
|
pTag |
Yes |
Sets the point to move the cursor after. |
Remarks
The MoveAfter function moves the cursor forward without retrieving information.
MoveBefore
The MoveBefore method moves the cursor before the given point.
Syntax
MoveBefore(pTag As Variant) As Long
Parameters
| Parameter | Required | Description | Variant |
|---|---|---|---|
|
pTag |
Yes |
Sets the point to move the cursor before. |
Remarks
The MoveBefore function moves the cursor backwards without retrieving information.
MoveFirst
The MoveFirst method moves to the first entry in the iteration list.
Syntax
MoveFirst() As Long
Remarks
Returns a value based on whether the method was successful or not (1 = Success; 0 = Failure).
Example
The following subroutine demonstrates the use of the Initialize, MoveFirst, and GetForward methods of the PointIterator object. It displays a list of all points in a VHS.
Sub ShowAllPoints (vhsService)
Dim vhsPointIter, vhsHistoryIter, tag, stat
lstPoints.ResetContent
Set vhsPointIter = CreateObject("CxVhsLib.PointIterator")
Set tag = CreateObject("CxVhsLib.HistoryTagStringEx")
Set stat = CreateObject("CxVhsLib.HistoryStats")
'Initialize point iterator with Short Point ID, going forward
vhsPointIter.Initialize vhsService, 0, 0
vhsPointIter.MoveFirst
'Show all points in a list box
While (vhsPointIter.GetForward(tag, stat))
lstPoints.AddString(tag.TagString)
Wend
End Sub
MoveLast
The MoveLast method moves to the last entry in the iteration list.
Syntax
MoveLast() As Long
Remarks
Returns a value based on whether the method was successful or not (1 = Success; 0 = Failure).
Example
The following subroutine demonstrates the use of the Initialize, MoveLast, and GetBackward methods of the PointIterator object. It displays a list of the last thirty points in a VHS.
Sub ShowLastThirty (vhsService)
Dim vhsPointIter, vhsHistoryIter, tag, stat, counter
lstPoints.ResetContent
counter = 0
Set vhsPointIter = CreateObject("CxVhsLib.PointIterator")
Set tag = CreateObject("CxVhsLib.HistoryTagStringEx")
Set stat = CreateObject("CxVhsLib.HistoryStats")
'Initialize point iterator with Long Point ID, going backward
vhsPointIter.Initialize vhsService, 1, 1
vhsPointIter.MoveLast
'Show all points in a list box
While ((vhsPointIter.GetBackward(tag, stat)) And (counter < 30))
lstPoints.AddString(tag.TagString)
counter = counter + 1;
Wend
End Sub
MoveTo
The MoveTo method moves the cursor to the given point.
Syntax
MoveTo(pTag As Variant) As Long
Parameters
| Parameter | Required | Description | Variant |
|---|---|---|---|
|
pTag |
Yes |
Sets the point to move the cursor to. |
Remarks
The MoveTo function moves the cursor without retrieving information.
Example
The following example demonstrates the use of MoveTo, Initialize, and GetForward. It jumps to a specified point and displays all the points after it in a list box.
Sub VhsMoveTo()
Dim VhsPointIter, Tag, Stat
Set VhsPointIter = CreateObject("CxVhsLib.PointIterator")
Set Tag = CreateObject("CxVhsLib.HistoryTagStringEx")
Set Stat = CreateObject("CxVhsLib.HistoryStats")
Tag.TagString = "CYGDEMO.VHS.00000068"
VhsPointIter.Initialize "CYGDEMO.VHS", 1, 1
VhsPointIter.MoveTo(Tag)
'Show remaining points in a list box
While ((VhsPointIter.GetForward(tag, stat))
lstPoints.AddString(tag.TagString)
Wend
End Sub
