DRAWITEM ... LISTBOX

Type NCCALCSIZEPARAM

rgrc(3) As RECT

lpos As WINDOWPOS

End Type

lParam

If wParam is TRUE, lParam points to an NCCALCSIZE_PARAMS structure that contains information an application can use to calculate the new size and position of the client rectangle.

If wParam is FALSE, lParam points to a RECTstructure. On entry, the structure contains the proposed window rectangle for the window. On exit, the structure should contain the screen coordinates of the corresponding window client area

Function fnListSubClass(ByVal hwnd As LongPtr,ByVal msg As Long,ByVal wParam As LongPtr,ByVal lParam As LongPtr)

Select Case msg

case WM_NCCALCSIZE

CallWindowProc listboxProc,hwnd,msg, wParam, lParam
'what is doing???
RECT* pRect = (RECT*)lParam
pRect->left+=4;
pRect->top+=23;
pRect->bottom+=23;
return 0;

case WM_NCPAINT

hdc=GetDC(hwnd) GetClientRect hwnd,rect
SetRect rect,0,0,4, rect.bottom brush=LoadBitmap(GetModuleHandle(0), MAKEINTRESOURCE(IDB_BORDER))
newBrush=CreatePatternBrush(brush)
oldBrush=SelectObject(hdc, newBrush) FillRect hdc,rect,newBrush SelectObject hdc, oldBrush
DeleteObject newBrush
DeleteObject oldBrush
DeleteObject brush
UpdateWindow hwnd
ReleaseDC hwnd, hdc
Exit Function



fnListSubClass=CallWindowProc(listboxProc, hwnd

(msg, wParam, lParam,

End Function 

Function WinProc(ByVal hwnd As LongPtr,ByVal msg As Long,ByVal wParam As LongPtr,ByVal lParam As 

(LongPtr

CASE WM_SHOWWINDOW,WM_CREATE 

listboxProc=SetWindowLongPtrA(listbox, GWL_WNDPROC,AddressOf fnListSubClass)

SendMessage listbox,WM_SETFONT, CreateFont=tahoma16, true

Case WM_DRAWITEM

Dim pdis AS DRAWITEMSTRUCT

CopyMemory pdis,ByVal lParam,40

if pdis.itemID=-1 Then Exit Function

Dim txt As String*40

SendMessage pdis.hwndItem,LB_GETTEXT,pdis.itemID, text

(itemLength=Len(text

if(pdis.itemAction=ODA_FOCUS Or pdis.itemState And ODS_FOCUS) Then 

(SetTextColor pdis.hDC,RGB(255,255,255

(SetBkColor pdis.hDC,RGB(51,94,168

FillRect pdis.hDC,pdis.rcItem

((CreateSolidBrush(RGB(51,94,168,

  

Else

(SetTextColor pdis.hDC,RGB(0,0,0

(SetBkColor pdis.hDC,RGB(255,255,255

FillRect pdis.hDC,pdis.rcItem

((CreateSolidBrush(RGB(255,255,255,

End if 

DrawTextExW pdis.hDC,text,itemLength, pdis.rcItem,DT_CENTER Or DT_END_ELLIPSIS,0

if(pdis.itemState=ODS_FOCUS) Then DrawFocusRect pdis.hDC,pdis.rcItem

End if 

CopyMemory ByVal lParam,pdis,40

Case WM_DESTROY

SetWindowLongPtrA hwnd,GWL_WNDPROC,listboxProc

WM_NCCREATE

We handle WM_NCCREATE because we want to associate so data with the LISTBOX and make a minor modification to the LISTBOX style. Creating our data is a simple and store in the window properties.

We modify the style by adding the WS_HSCROLL if the LISTBOX doesn't already have it. Without this style the horizontal scrollbar won't show no matter what we do.

WM_NCDESTROY

Here we simply destroy our data structure and remove it from the window properties. Nothing exciting.

مثالی دیگر از مطالب به اشتراک گذاشته در سایت خارجی 

Code:

Private Sub Form_Load()
 Dim I As Integer
    
 For I = 15 To 0 Step -1
   'Load a List of 0 to 15 with the Item Data
   'Set to the QBColors 0 - 15
   List1.AddItem "Color " & I
   List1.itemData(List1.NewIndex) = QBColor(I)
 Next
    
 For I = 0 To 15
   'Load a List of 0 to 15 with the Item Data
   'Set to the QBColors 0 - 15
   List2.AddItem "Color " & I
   List2.itemData(List2.NewIndex) = QBColor(I)
 Next
    
 'Subclass the "Form", to Capture the Listbox Notification Messages
 lPrevWndProc = SetWindowLong(hwnd, GWL_WNDPROC, AddressOf SubClassedList)
End Sub

Private Sub Form_Unload(Cancel As Integer)
 'Release the SubClassing, Very Import to Prevent Crashing!
 Call SetWindowLong(hwnd, GWL_WNDPROC, lPrevWndProc)
End Sub

.BAS Code

Code:

Option Explicit

Public Type RECT
        Left As Long
        Top As Long
        Right As Long
        Bottom As Long
End Type

Public Type DRAWITEMSTRUCT
        CtlType As Long
        CtlID As Long
        itemID As Long
        itemAction As Long
        itemState As Long
        hwndItem As Long
        hdc As Long
        rcItem As RECT
        itemData As Long
End Type

Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)

Public Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Public Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" (ByVal lpPrevWndFunc As Long, ByVal hwnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Public Declare Function CreateSolidBrush Lib "gdi32" (ByVal crColor As Long) As Long
Public Declare Function FillRect Lib "user32" (ByVal hdc As Long, lpRect As RECT, ByVal hBrush As Long) As Long
Public Declare Function DeleteObject Lib "gdi32" (ByVal hObject As Long) As Long
Public Declare Function SetBkColor Lib "gdi32" (ByVal hdc As Long, ByVal crColor As Long) As Long
Public Declare Function SetTextColor Lib "gdi32" (ByVal hdc As Long, ByVal crColor As Long) As Long
Public Declare Function TextOut Lib "gdi32" Alias "TextOutA" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long, ByVal lpString As String, ByVal nCount As Long) As Long
Public Declare Function DrawFocusRect Lib "user32" (ByVal hdc As Long, lpRect As RECT) As Long
Public Declare Function GetSysColor Lib "user32" (ByVal nIndex As Long) As Long

Public Const COLOR_HIGHLIGHT = 13
Public Const COLOR_HIGHLIGHTTEXT = 14
Public Const COLOR_WINDOW = 5
Public Const COLOR_WINDOWTEXT = 8
Public Const LB_GETTEXT = &H189
Public Const WM_DRAWITEM = &H2B
Public Const GWL_WNDPROC = (-4)
Public Const ODS_FOCUS = &H10
Public Const ODT_LISTBOX = 2

Public lPrevWndProc As Long

Public Function SubClassedList(ByVal hwnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
 Dim tItem As DRAWITEMSTRUCT
 Dim sBuff As String * 255
 Dim sItem As String
 Dim lBack As Long
    
 If Msg = WM_DRAWITEM Then
   'Redraw the listbox
   'This function only passes the Address of the DrawItem Structure, so we need to
   'use the CopyMemory API to Get a Copy into the Variable we setup:
   Call CopyMemory(tItem, ByVal lParam, Len(tItem))
        
   'Make sure we're dealing with a Listbox
   If tItem.CtlType = ODT_LISTBOX Then
     'Get the Item Text
     Call SendMessage(tItem.hwndItem, LB_GETTEXT, tItem.itemID, ByVal sBuff)
            
     sItem = Left(sBuff, InStr(sBuff, Chr(0)) - 1)
            
     If (tItem.itemState And ODS_FOCUS) Then
       'Item has Focus, Highlight it, I'm using the Default Focus
       'Colors for this example.
       lBack = CreateSolidBrush(GetSysColor(COLOR_HIGHLIGHT))
                
       Call FillRect(tItem.hdc, tItem.rcItem, lBack)
       Call SetBkColor(tItem.hdc, GetSysColor(COLOR_HIGHLIGHT))
       Call SetTextColor(tItem.hdc, GetSysColor(COLOR_HIGHLIGHTTEXT))
       TextOut tItem.hdc, tItem.rcItem.Left, tItem.rcItem.Top, ByVal sItem, Len(sItem)
       DrawFocusRect tItem.hdc, tItem.rcItem
     Else
       'Item Doesn't Have Focus, Draw it's Colored Background
       'Create a Brush using the Color we stored in ItemData
       lBack = CreateSolidBrush(tItem.itemData)
       'Paint the Item Area
       Call FillRect(tItem.hdc, tItem.rcItem, lBack)
                
       'Set the Text Colors
       Call SetBkColor(tItem.hdc, tItem.itemData)
       Call SetTextColor(tItem.hdc, IIf(tItem.itemData = vbBlack, vbWhite, vbBlack))
       
       'Display the Item Text
       TextOut tItem.hdc, tItem.rcItem.Left, tItem.rcItem.Top, ByVal sItem, Len(sItem)
     End If
            
     Call DeleteObject(lBack)
     
     'Don't Need to Pass a Value on as we've just handled the Message ourselves
     SubClassedList = 0
     Exit Function
   End If
 End If
    
 SubClassedList = CallWindowProc(lPrevWndProc, hwnd, Msg, wParam, lParam)
End Function

فقط در CopyMemory سایز ۴۰ را به آرگومان سومش تخصیص دهید و از ByVal lParam استفاده کنید.

در مورد LB_GETTEXT  : 

Return value

The return value is the length of the string, in TCHARs, excluding the terminating null character. If wParam does not specify a valid index, the return value is LB_ERR.

     Remarks

If the list box has an owner-drawn style but not the LBS_HASSTRINGS style, the buffer pointed to by the lParam parameter receives the value associated with the item (the item 

(data