[VB] Create Button

Option Explicit

'==================================================================
' modExtButton.bas
' From Visual Basic Thunder, www.vbthunder.com
'
' This module provides an easy way to change the text color
' of a VB CommandButton control. To use the code with a
' CommandButton, you should:
'
' - Set the button's Style property to "Graphical" at
' design time.
'
' - Optionally set its BackColor and Picture properties.
'
' - Call SetButton in the Form_Load event:
' SetButton Command1.hWnd, vbBlue
' (You can do this multiple times during your program's
' execution, even without calling RemoveButton.)
'
' - Call RemoveButton in the Form_Unload event:
' RemoveButton Command1.hWnd
'
'==================================================================

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

Private Declare Function GetParent Lib "user32" _
(ByVal hWnd As Long) As Long

Private Declare Function GetWindowLong Lib "user32" Alias _
"GetWindowLongA" (ByVal hWnd As Long, _
ByVal nIndex As Long) As Long
Private Declare Function SetWindowLong Lib "user32" Alias _
"SetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long, _
ByVal dwNewLong As Long) As Long
Private Const GWL_WNDPROC = (-4)

Private Declare Function GetProp Lib "user32" Alias "GetPropA" _
(ByVal hWnd As Long, ByVal lpString As String) As Long
Private Declare Function SetProp Lib "user32" Alias "SetPropA" _
(ByVal hWnd As Long, ByVal lpString As String, _
ByVal hData As Long) As Long
Private Declare Function RemoveProp Lib "user32" Alias _
"RemovePropA" (ByVal hWnd As Long, _
ByVal lpString As String) As Long

Private 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

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

'Owner draw constants
Private Const ODT_BUTTON = 4
Private Const ODS_SELECTED = &H1
'Window messages we're using
Private Const WM_DESTROY = &H2
Private Const WM_DRAWITEM = &H2B

Private 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

Private Declare Function GetWindowText Lib "user32" Alias _
"GetWindowTextA" (ByVal hWnd As Long, ByVal lpString As String, _
ByVal cch As Long) As Long
'Various GDI painting-related functions
Private Declare Function DrawText Lib "user32" Alias "DrawTextA" _
(ByVal hDC As Long, ByVal lpStr As String, ByVal nCount As Long, _
lpRect As RECT, ByVal wFormat As Long) As Long
Private Declare Function SetTextColor Lib "gdi32" (ByVal hDC As Long, _
ByVal crColor As Long) As Long
Private Declare Function SetBkMode Lib "gdi32" (ByVal hDC As Long, _
ByVal nBkMode As Long) As Long
Private Const TRANSPARENT = 1

Private Const DT_CENTER = &H1
Public Enum TextVAligns
DT_VCENTER = &H4
DT_BOTTOM = &H8
End Enum
Private Const DT_SINGLELINE = &H20


Private Sub DrawButton(ByVal hWnd As Long, ByVal hDC As Long, _
rct As RECT, ByVal nState As Long)

Dim s As String
Dim va As TextVAligns

va = GetProp(hWnd, "VBTVAlign")

'Prepare DC for drawing
SetBkMode hDC, TRANSPARENT
SetTextColor hDC, GetProp(hWnd, "VBTForeColor")

'Prepare a text buffer
s = String$(255, 0)
'What should we print on the button?
GetWindowText hWnd, s, 255
'Trim off nulls
s = Left$(s, InStr(s, Chr$(0)) - 1)

If va = DT_BOTTOM Then
'Adjust specially for VB's CommandButton control
rct.Bottom = rct.Bottom - 4
End If

If (nState And ODS_SELECTED) = ODS_SELECTED Then
'Button is in down state - offset
'the text
rct.Left = rct.Left + 1
rct.Right = rct.Right + 1
rct.Bottom = rct.Bottom + 1
rct.Top = rct.Top + 1
End If

DrawText hDC, s, Len(s), rct, DT_CENTER Or DT_SINGLELINE _
Or va

End Sub

Public Function ExtButtonProc(ByVal hWnd As Long, _
ByVal wMsg As Long, ByVal wParam As Long, _
ByVal lParam As Long) As Long

Dim lOldProc As Long
Dim di As DRAWITEMSTRUCT

lOldProc = GetProp(hWnd, "ExtBtnProc")

ExtButtonProc = CallWindowProc(lOldProc, hWnd, wMsg, wParam, lParam)

If wMsg = WM_DRAWITEM Then
CopyMemory di, ByVal lParam, Len(di)
If di.CtlType = ODT_BUTTON Then
If GetProp(di.hwndItem, "VBTCustom") = 1 Then
DrawButton di.hwndItem, di.hDC, di.rcItem, _
di.itemState

End If

End If

ElseIf wMsg = WM_DESTROY Then
ExtButtonUnSubclass hWnd

End If

End Function

Public Sub ExtButtonSubclass(hWndForm As Long)

Dim l As Long

l = GetProp(hWndForm, "ExtBtnProc")
If l <> 0 Then
'Already subclassed
Exit Sub
End If

SetProp hWndForm, "ExtBtnProc", _
GetWindowLong(hWndForm, GWL_WNDPROC)
SetWindowLong hWndForm, GWL_WNDPROC, AddressOf ExtButtonProc

End Sub

Public Sub ExtButtonUnSubclass(hWndForm As Long)

Dim l As Long

l = GetProp(hWndForm, "ExtBtnProc")
If l = 0 Then
'Isn't subclassed
Exit Sub
End If

SetWindowLong hWndForm, GWL_WNDPROC, l
RemoveProp hWndForm, "ExtBtnProc"

End Sub

Public Sub SetButton(ByVal hWnd As Long, _
ByVal lForeColor As Long, _
Optional ByVal VAlign As TextVAligns = DT_VCENTER)

Dim hWndParent As Long

hWndParent = GetParent(hWnd)
If GetProp(hWndParent, "ExtBtnProc") = 0 Then
ExtButtonSubclass hWndParent
End If

SetProp hWnd, "VBTCustom", 1
SetProp hWnd, "VBTForeColor", lForeColor
SetProp hWnd, "VBTVAlign", VAlign

End Sub

Public Sub RemoveButton(ByVal hWnd As Long)

RemoveProp hWnd, "VBTCustom"
RemoveProp hWnd, "VBTForeColor"
RemoveProp hWnd, "VBTVAlign"

End Sub