Virtual listviews (Data stored in databases mode) change to a buffer for 100 items at once?

[kklee69]

I got an example from LarsJ's  Virtual listviews 

Virtual listviews  Data stored in databases

This is very cool code

But when I press the scroll next to

The program only buffers one data at a time

I think this will cause the SERVER to be too busy

I want to change into a buffer of 100 items

Can someone help me??

database

Test3.rar

 

expandcollapse popup

#include <GUIConstants.au3>
#include <WindowsConstants.au3>
#include <GuiListView.au3>
#include <SQLite.au3>

;Opt( "MustDeclareVars", 1 )

Global Const $tagNMLVCACHEHINT = $tagNMHDR & ";int iFrom;int iTo"

Global $hLV,$conn




Example()


Func Example()
    _SQLite_Startup()

    ; Check databases
    Local $iRows3 = CheckDB( "Test3.db" )
    Local $iRows

    ; Create GUI
    GUICreate( "Virtual ListViews", 850, 400 )

    ; Create Tab
    Local $idTab = GUICtrlCreateTab( 10, 10, 850-20, 400-20 )
    GUICtrlCreateTabItem( "Test3.db: " & Format( $iRows3 ) & " rows" )
    GUICtrlCreateTabItem( "" )

    ; Create ListView
    Local $idLV = GUICtrlCreateListView( "", 20, 40, 850-40, 400-50, $LVS_OWNERDATA, BitOR( $WS_EX_CLIENTEDGE, $LVS_EX_DOUBLEBUFFER, $LVS_EX_FULLROWSELECT ) )
    $hLV = GUICtrlGetHandle( $idLV ) ;                               Virtual listview                          Reduces flicker
    For $i = 0 To 9
        _GUICtrlListView_AddColumn( $hLV, "Col" & $i, 75 )
    Next

    GUIRegisterMsg( $WM_NOTIFY, "WM_NOTIFY" )
    GUISetState( @SW_SHOW )

    ; Data for first tab
    $iRows = $iRows3
    If $iRows Then _SQLite_Open( "Test3.db" )
    GUICtrlSendMsg( $idLV, $LVM_SETITEMCOUNT, $iRows, 0 )

    ; Message loop
    While 1
        Switch GUIGetMsg()
            Case $idTab
                If $iRows Then _SQLite_Close( -1 )
                Switch GUICtrlRead( $idTab )
                    Case 0
                        $iRows = $iRows1
                        If $iRows Then _SQLite_Open( "Test1.db" )
                    Case 1
                        $iRows = $iRows2
                        If $iRows Then _SQLite_Open( "Test2.db" )
                    Case 2
                        $iRows = $iRows3
                        If $iRows Then _SQLite_Open( "Test3.db" )
                EndSwitch
                GUICtrlSendMsg( $idLV, $LVM_SETITEMCOUNT, $iRows, 0 )

            Case $GUI_EVENT_CLOSE
                ExitLoop
        EndSwitch
    WEnd

    If $iRows Then _SQLite_Close( -1 )
    _SQLite_Shutdown()
    GUIDelete()
EndFunc

Func WM_NOTIFY( $hWnd, $iMsg, $wParam, $lParam )
    Local Static $tText = DllStructCreate( "wchar[50]" )
    Local Static $pText = DllStructGetPtr( $tText )
    Local Static $aResult, $iRows, $iFrom

    Local $tNMHDR, $hWndFrom, $iCode
    $tNMHDR = DllStructCreate( $tagNMHDR, $lParam )
    $hWndFrom = HWnd( DllStructGetData( $tNMHDR, "hWndFrom" ) )
    $iCode = DllStructGetData( $tNMHDR, "Code" )

    Switch $hWndFrom

        Case $hLV

            Switch $iCode

                Case $LVN_GETDISPINFOW
                    Local $tNMLVDISPINFO = DllStructCreate( $tagNMLVDISPINFO, $lParam )
                    If BitAND( DllStructGetData( $tNMLVDISPINFO, "Mask" ), $LVIF_TEXT ) Then
                        Local $iIndex = DllStructGetData( $tNMLVDISPINFO, "Item" ) - $iFrom + 1
                        If $iIndex > 0 And $iIndex < $iRows + 1 Then
                            Local $sItem = $aResult[$iIndex][DllStructGetData($tNMLVDISPINFO,"SubItem")]
                            DllStructSetData( $tText, 1, $sItem )
                            DllStructSetData( $tNMLVDISPINFO, "Text", $pText )
                            DllStructSetData( $tNMLVDISPINFO, "TextMax", StringLen( $sItem ) )
                        EndIf
                    EndIf

                Case $LVN_ODCACHEHINT
                    Local $tNMLVCACHEHINT = DllStructCreate( $tagNMLVCACHEHINT, $lParam ), $iColumns
                    $iFrom = DllStructGetData( $tNMLVCACHEHINT, "iFrom" )
                    $iTo=DllStructGetData( $tNMLVCACHEHINT, "iTo" )
                    Local $sSQL = "SELECT * FROM lvdata WHERE item_id >= " & $iFrom & _
                        " AND item_id <= " & DllStructGetData( $tNMLVCACHEHINT, "iTo" ) & ";"
                        
                        ConsoleWrite($iFrom&" "&$iTo&@CRLF)
                        
                    _SQLite_GetTable2d( -1, $sSQL, $aResult, $iRows, $iColumns )
                    
                    
                    

            EndSwitch

    EndSwitch

    Return $GUI_RUNDEFMSG
EndFunc

Func CheckDB( $sDBname )
    Local $aRow, $iRows = 0
    If FileExists( $sDBname ) Then
        _SQLite_Open( $sDBname )
        _SQLite_QuerySingleRow( -1, "SELECT max(item_id) FROM lvdata;", $aRow )
        _SQLite_Close( -1 )
    EndIf
    If IsArray( $aRow ) Then _
        $iRows = $aRow[0] + 1
    Return $iRows
EndFunc

Func Format( $iInt )
    Return StringRegExpReplace( $iInt, "(\A\d{1,3}(?=(\d{3})+\z)|\d{3}(?=\d))", "\1," )
EndFunc