Pager Control (VBCCRPager)

VBCCRPager control provides a pagination navigation interface for browsing and navigating through large amounts of data. It is typically used in conjunction with ListView or other data display controls.

Properties

Key Properties

• Position: Current position
• Min: Minimum position value
• Max: Maximum position value
• SmallChange: Change amount when clicking arrow buttons
• LargeChange: Change amount when clicking page area
• Orientation: Direction (horizontal or vertical)
• Mode: Paging mode
• ButtonSize: Button size
• BackColor: Background color
• Enabled: Enable/disable the control

Methods

Main Methods

• SetPosition(Position As Long): Set current position
• GetPosition() As Long: Get current position
• Refresh(): Refresh display

Events

• Change(): Triggered when position changes
• Click(): Triggered when clicked
• PageClick(ByVal Part As PagerPartConstants): Triggered when clicking paging parts
• Scroll(): Triggered when scrolling

Code Examples

Basic Usage

Private Sub Form_Load()
    With Pager1
        .Min = 0
        .Max = 100
        .SmallChange = 1
        .LargeChange = 10
        .Position = 0
        .Orientation = OrientationHorizontal
    End With
End Sub

Integration with ListView

Private Sub SetupListViewPager()
    ' Set up pager
    With Pager1
        .Min = 0
        .Max = GetTotalPages() - 1
        .SmallChange = 1
        .LargeChange = 1
        .Position = 0
    End With
    
    ' Initial data load
    LoadListViewPage Pager1.Position
End Sub

Private Sub Pager1_Change()
    LoadListViewPage Pager1.Position
End Sub

Private Sub LoadListViewPage(ByVal PageIndex As Long)
    Const PAGE_SIZE As Long = 20
    Dim StartIndex As Long
    Dim EndIndex As Long
    
    StartIndex = PageIndex * PAGE_SIZE
    EndIndex = StartIndex + PAGE_SIZE - 1
    
    ListView1.ListItems.Clear
    LoadDataIntoListView StartIndex, EndIndex
End Sub

Custom Pagination Display

Private Sub CustomizePager()
    With Pager1
        .ButtonSize = 20
        .Mode = PagerModePage ' Page mode
        
        ' Set total pages
        .Max = (TotalRecords + PageSize - 1) \ PageSize - 1
        
        ' Set current page
        .Position = 0
    End With
    
    ' Update page information display
    UpdatePageInfo
End Sub

Private Sub UpdatePageInfo()
    lblPageInfo.Caption = "Page " & (Pager1.Position + 1) & " of " & _
                         (Pager1.Max + 1)
End Sub

Common Use Cases

Data Browser

Private Sub SetupDataBrowser()
    ' Initialize pager control
    With Pager1
        .Orientation = OrientationHorizontal
        .Mode = PagerModePage
        .ButtonSize = 25
        .Min = 0
        .Max = (RecordCount - 1) \ PageSize
        .Position = 0
    End With
    
    ' Load first page
    LoadData Pager1.Position * PageSize, PageSize
End Sub

Private Sub Pager1_Change()
    ' Load new page data
    Dim StartIndex As Long
    StartIndex = Pager1.Position * PageSize
    LoadData StartIndex, PageSize
    UpdatePageInfo
End Sub

Image Browser

Private Sub SetupImageBrowser()
    ' Set up image browser paging
    With Pager1
        .Orientation = OrientationHorizontal
        .ButtonSize = 30
        .Min = 0
        .Max = ImageCount - 1
        .Position = 0
        .SmallChange = 1
        .LargeChange = 1
    End With
    
    ' Show first image
    ShowImage Pager1.Position
End Sub

Private Sub ShowImage(ByVal Index As Long)
    On Error GoTo ErrorHandler
    
    PictureBox1.Picture = LoadPicture(ImageFiles(Index))
    lblImageInfo.Caption = "Image " & (Index + 1) & " / " & ImageCount
    Exit Sub
    
ErrorHandler:
    MsgBox "Cannot load image: " & Err.Description
End Sub

Best Practices

1. Position Validation

Private Function ValidatePosition(ByVal NewPosition As Long) As Long
    ' Ensure position is within valid range
    If NewPosition < Pager1.Min Then
        ValidatePosition = Pager1.Min
    ElseIf NewPosition > Pager1.Max Then
        ValidatePosition = Pager1.Max
    Else
        ValidatePosition = NewPosition
    End If
End Function

2. Error Handling

Private Sub SafePagerOperation()
    On Error GoTo ErrorHandler
    
    Dim NewPosition As Long
    NewPosition = Pager1.Position + Pager1.SmallChange
    Pager1.Position = ValidatePosition(NewPosition)
    Exit Sub
    
ErrorHandler:
    Debug.Print "Paging operation error: " & Err.Description
End Sub

Known Issues and Solutions

1. Performance Optimization

Private Sub OptimizePagerPerformance()
    ' Disable redraw when loading large amounts of data
    Pager1.Enabled = False
    
    ' Perform data loading
    LoadBulkData
    
    Pager1.Enabled = True
    Pager1.Refresh
End Sub

2. UI Response Issues

Private Sub HandleUIResponse()
    Screen.MousePointer = vbHourglass
    
    ' Perform time-consuming operation
    ProcessPageData
    
    Screen.MousePointer = vbDefault
End Sub

Additional Tips

• Provide clear page feedback
• Implement keyboard navigation
• Display loading status
• Optimize data loading
• Handle edge cases
• Display page information
• Implement caching mechanism
• Consider accessibility
• Maintain UI responsiveness
• Clean up resources in Form_Unload

Special Uses

1. Creating Infinite Scroll

Private Sub CreateInfiniteScroll()
    With Pager1
        .Mode = PagerModeScroll
        .Max = 1000000 ' Set a large value
        .SmallChange = 1
        .LargeChange = 10
    End With
End Sub

Private Sub Pager1_Change()
    ' Check if more data needs to be loaded
    If Pager1.Position >= LastLoadedPosition Then
        LoadMoreData
    End If
End Sub

2. Creating Thumbnail Preview

Private Sub CreateThumbnailPager()
    ' Set up thumbnail paging
    With Pager1
        .Orientation = OrientationHorizontal
        .Mode = PagerModePage
        .ButtonSize = 50 ' Larger buttons to accommodate thumbnails
    End With
    
    LoadThumbnails
End Sub

3. Creating Group Paging

Private Sub CreateGroupPager()
    ' Set up group paging
    With Pager1
        .Mode = PagerModePage
        .SmallChange = 1
        .LargeChange = GroupSize
    End With
    
    ' Load group data
    LoadGroupData Pager1.Position
End Sub