DOCUMENT:Q170884 01-JUL-1997 [vbwin] TITLE :HOWTO: Sort a ListView Control by Date PRODUCT :Microsoft Visual Basic for Windows PROD/VER:5.0 OPER/SYS:WINDOWS KEYWORDS:vb5all vb5howto VBKBAX VBKBComp VBKBCtrl kbhowto ====================================================================== --------------------------------------------------------------------- The information in this article applies to: - Microsoft Visual Basic Control Creation, Learning, Professional, and Enterprise Editions for Windows, version 5.0 --------------------------------------------------------------------- SUMMARY ======= When using a Listview control, you can set the Sorted property for the control to sort the list alphabetically. However, the Listview control does not expose a property or method for sorting a list by date. This article presents a method that you can use to sort a Listview control by date. MORE INFORMATION ================ To sort data in a ListView control by date, it is necessary to provide a comparison function to the control via AddressOf. NOTE: Using this approach, you will sort the data in the control but not the ListItems collection. Therefore, if you must read the data from the list in sorted order, it is necessary to step through the actual list rather than the ListItems collection. Step-by-Step Example -------------------- 1. Start a new Visual Basic project. Form1 is created by default. 2. Click Components on the Project menu. Check "Microsoft Windows Common Controls 5.0" and click OK. 3. Add a Module to the project. 4. Draw a ListView control on Form1. 5. Add the following code to Form1: Option Explicit Private Sub Form_Load() Dim clmAdd As ColumnHeader Dim itmAdd As ListItem 'Add two Column Headers to the ListView control Set clmAdd = ListView1.ColumnHeaders.Add(Text:="Name") Set clmAdd = ListView1.ColumnHeaders.Add(Text:="Date") 'Set the view property of the Listview control to Report view ListView1.View = lvwReport 'Add data to the ListView control Set itmAdd = ListView1.ListItems.Add(Text:="Joe") itmAdd.SubItems(1) = "05/07/97" Set itmAdd = ListView1.ListItems.Add(Text:="Sally") itmAdd.SubItems(1) = "04/08/97" Set itmAdd = ListView1.ListItems.Add(Text:="Bill") itmAdd.SubItems(1) = "05/29/97" Set itmAdd = ListView1.ListItems.Add(Text:="Fred") itmAdd.SubItems(1) = "05/17/97" Set itmAdd = ListView1.ListItems.Add(Text:="Anne") itmAdd.SubItems(1) = "04/01/97" End Sub Private Sub ListView1_ColumnClick(ByVal ColumnHeader As _ ComctlLib.ColumnHeader) Dim strName As String Dim dDate As Date Dim lngItem As Long 'Handle User click on column header If ColumnHeader.Tag = "Name" Then 'User clicked on Name header ListView1.Sorted = True 'Use default sorting to sort the ListView1.SortKey = 0 'items in the list Else ListView1.Sorted = False 'User clicked on the Date header 'Use our sort routine to sort 'by date SendMessage ListView1.hWnd, _ LVM_SORTITEMS, _ ListView1.hWnd, _ AddressOf CompareDates End If 'Refresh the ListView before writing the data ListView1.Refresh 'Loop through the items in the List to print them out in 'sorted order. 'NOTE: You are looping through the ListView control because when _ 'sorting by date the ListItems collection won't be sorted. For lngItem = 0 To ListView1.ListItems.Count - 1 ListView_GetListItem lngItem, ListView1.hWnd, strName, dDate Next End Sub 6. Add the following code to Module1: Option Explicit 'Structures Public Type POINT x As Long y As Long End Type Public Type LV_FINDINFO flags As Long psz As String lParam As Long pt As POINT vkDirection As Long End Type Public Type LV_ITEM mask As Long iItem As Long iSubItem As Long State As Long stateMask As Long pszText As Long cchTextMax As Long iImage As Long lParam As Long iIndent As Long End Type 'Constants Private Const LVFI_PARAM = 1 Private Const LVIF_TEXT = &H1 Private Const LVM_FIRST = &H1000 Private Const LVM_FINDITEM = LVM_FIRST + 13 Private Const LVM_GETITEMTEXT = LVM_FIRST + 45 Public Const LVM_SORTITEMS = LVM_FIRST + 48 'API declarations Declare Function SendMessage Lib "user32" Alias "SendMessageA" ( _ ByVal hWnd As Long, _ ByVal wMsg As Long, _ ByVal wParam As Long, _ ByVal lParam As Long) As Long 'Module Functions and Procedures 'CompareDates: This is the sorting routine that gets passed to the 'ListView control to provide the comparison test for date values. Public Function CompareDates(ByVal lngParam1 As Long, _ ByVal lngParam2 As Long, _ ByVal hWnd As Long) As Long Dim strName1 As String Dim strName2 As String Dim dDate1 As Date Dim dDate2 As Date 'Obtain the item names and dates corresponding to the 'input parameters ListView_GetItemData lngParam1, hWnd, strName1, dDate1 ListView_GetItemData lngParam2, hWnd, strName2, dDate2 'Compare the dates 'Return 0 ==> Less Than ' 1 ==> Equal ' 2 ==> Greater Than If dDate1 < dDate2 Then CompareDates = 0 ElseIf dDate1 = dDate2 Then CompareDates = 1 Else CompareDates = 2 End If End Function 'GetItemData - Given Retrieves Public Sub ListView_GetItemData(lngParam As Long, _ hWnd As Long, _ strName As String, _ dDate As Date) Dim objFind As LV_FINDINFO Dim lngIndex As Long Dim objItem As LV_ITEM Dim baBuffer(32) As Byte Dim lngLength As Long ' ' Convert the input parameter to an index in the list view ' objFind.flags = LVFI_PARAM objFind.lParam = lngParam lngIndex = SendMessage(hWnd, LVM_FINDITEM, -1, VarPtr(objFind)) ' ' Obtain the name of the specified list view item ' objItem.mask = LVIF_TEXT objItem.iSubItem = 0 objItem.pszText = VarPtr(baBuffer(0)) objItem.cchTextMax = UBound(baBuffer) lngLength = SendMessage(hWnd, LVM_GETITEMTEXT, lngIndex, _ VarPtr(objItem)) strName = Left$(StrConv(baBuffer, vbUnicode), lngLength) ' ' Obtain the modification date of the specified list view item ' objItem.mask = LVIF_TEXT objItem.iSubItem = 1 objItem.pszText = VarPtr(baBuffer(0)) objItem.cchTextMax = UBound(baBuffer) lngLength = SendMessage(hWnd, LVM_GETITEMTEXT, lngIndex, _ VarPtr(objItem)) If lngLength > 0 Then dDate = CDate(Left$(StrConv(baBuffer, vbUnicode), lngLength)) End If End Sub 'GetListItem - This is a modified version of ListView_GetItemData ' It takes an index into the list as a parameter and returns ' the appropriate values in the strName and dDate parameters. Public Sub ListView_GetListItem(lngIndex As Long, _ hWnd As Long, _ strName As String, _ dDate As Date) Dim objItem As LV_ITEM Dim baBuffer(32) As Byte Dim lngLength As Long ' ' Obtain the name of the specified list view item ' objItem.mask = LVIF_TEXT objItem.iSubItem = 0 objItem.pszText = VarPtr(baBuffer(0)) objItem.cchTextMax = UBound(baBuffer) lngLength = SendMessage(hWnd, LVM_GETITEMTEXT, lngIndex, _ VarPtr(objItem)) strName = Left$(StrConv(baBuffer, vbUnicode), lngLength) ' ' Obtain the modification date of the specified list view item ' objItem.mask = LVIF_TEXT objItem.iSubItem = 1 objItem.pszText = VarPtr(baBuffer(0)) objItem.cchTextMax = UBound(baBuffer) lngLength = SendMessage(hWnd, LVM_GETITEMTEXT, lngIndex, _ VarPtr(objItem)) If lngLength > 0 Then dDate = CDate(Left$(StrConv(baBuffer, vbUnicode), lngLength)) End If End Sub 7. Save your project. 8. Press the F5 key to run the application. Click on the Date column header to sort the items in the list by date. ====================================================================== Keywords : vb5all vb5howto VBKBAX VBKBComp VBKBCtrl kbhowto Version : 5.0 Platform : WINDOWS ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 1997.