ListView Control loads very slowly
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03-07-2019 - |
Question
What is the fastest way to fill ListView from query when it has over 15000 lists with 9 subitems. it is taking me about 6 minute to load.
Here is what I wrote to fill ListView control.
Set rs = db.OpenRecordset(strSQL, dbOpenForwardOnly, dbReadOnly)
With Me.listViewData
.View = lvwReport
.GridLines = True
.FullRowSelect = True
.ListItems.Clear
.ColumnHeaders.Clear
End With
'Set up column headers
With Me.listViewData.ColumnHeaders
.Add , , "Client", 1440, lvwColumnLeft
.Add , , "Contact", 2160, lvwColumnLeft
.Add , , "Quote #", 720, lvwColumnCenter
.Add , , "Date", 1140, lvwColumnLeft
.Add , , "GrandTotal", 1440, lvwColumnRight
.Add , , "Weighted Value", 1440, lvwColumnRight
.Add , , "Chance %", 500, lvwColumnRight
.Add , , "Sales Cycle", 1140, lvwColumnRight
.Add , , "Won Orders", 1000, lvwColumnRight
.Add , , "SalesRep", 1000, lvwColumnRight
End With
While Not rs.EOF
Set lstItem = Me.listViewData.ListItems.Add()
lstItem.Text = Nz(rs!Name, "")
lstItem.SubItems(1) = Nz(rs!Company, "")
lstItem.SubItems(2) = Nz(rs!QuoteNumber, "")
lstItem.SubItems(3) = Nz(rs!OrderDate, "")
lstItem.SubItems(4) = Nz(Format(rs!GrandTotal, "Currency"), "0.00")
lstItem.SubItems(5) = Nz(Format(rs!GrandTotal * rs!Customfield1 / 100, "Currency"), "")
lstItem.SubItems(6) = Nz(rs!Customfield1, "")
lstItem.SubItems(7) = Nz(rs!Date1, "none")
lstItem.SubItems(8) = Nz(rs!Detail, "")
lstItem.SubItems(9) = Nz(rs!CustomT1, Nz(rs!UserID, ""))
For I = 1 To Me.listViewData.ColumnHeaders.Count - 1
Set sb = lstItem.ListSubItems(I)
If rs!Customfield1 = 100 Or Not IsNull(rs!List) Then
sb.ForeColor = vbBlue
lstItem.ForeColor = vbBlue
ElseIf rs!Cancelled = -1 Then
sb.ForeColor = vbRed
lstItem.ForeColor = vbRed
Else
sb.ForeColor = vbBlack
lstItem.ForeColor = vbBlack
End If
DoEvents
Next
rs.MoveNext
Wend
Solution 2
I can think of a couple things:
While...Wend is a slower looping mechanism; use For...Next. For...Next is faster--even if you have to run another command to get the RecordCount. This is what I use:
With rs
If .RecordCount > 0 Then
'-- MoveLast...MoveFirst will update the .RecordCount; depending on the type of DAO Recordset, RecordCount might only return "1" when there are more than that.
.MoveLast
.MoveFirst
For lngCounter = 1 To .RecordCount
'-- Code to add ListItems here
.MoveNext
Next lngCounter
End If
.Close
End With
Use With...End With for adding your SubItems:
With Me.listViewData.ListItems.Add
.Text = Nz(rs!Name, "")
.SubItems(1) = Nz(rs!Company, "")
.SubItems(2) = Nz(rs!QuoteNumber, "")
.SubItems(3) = Nz(rs!OrderDate, "")
.SubItems(4) = Nz(Format(rs!GrandTotal, "Currency"), "0.00")
.SubItems(5) = Nz(Format(rs!GrandTotal * rs!Customfield1 / 100, "Currency"), "")
.SubItems(6) = Nz(rs!Customfield1, "")
.SubItems(7) = Nz(rs!Date1, "none")
.SubItems(8) = Nz(rs!Detail, "")
.SubItems(9) = Nz(rs!CustomT1, Nz(rs!UserID, ""))
End With
Wrap the populater code in:
DoCmd.Echo False
'-- Populate code
DoCmd.Echo True
Hope that helps!
OTHER TIPS
The first thing is you should do is get rid of the "doevents" That's a real performance killer.
Do you have to load the listview dynamically? Why not bind it directly to a datasource?
Check the methods of the Listview control for something like beginupdate / endupdate or set refresh to false (if possible). This means that the UI will not try to refresh the screen after each item is added, thereby making the adding much quicker.
The Listview control is designed to take large numbers of items so it should be possible with a bit of digging.