Option Explicit

Declare Function SetWindowLong Lib "user32"  _
  Alias "SetWindowLongA" (ByVal hWnd As Long,  _
  ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Declare Function GetWindowLong Lib "user32"  _
  Alias "GetWindowLongA" (ByVal hWnd As Long, _
  ByVal nIndex As Long) As Long
Declare Function CallWindowProc Lib "user32" _
  Alias "CallWindowProcA" (ByVal wndrpcPrev As Long, _　　　　　　　
  ByVal hWnd As Long, ByVal uMsg As Long,  _
  ByVal wParam As Long, lParam As Any) As Long
Public Const GWL_WNDPROC = -4

Declare Function GetSystemMenu Lib "user32" _
 (ByVal hWnd As Long, ByVal bRevert As Long) As Long
Declare Function AppendMenu Lib "user32"  _
  Alias "AppendMenuA" (ByVal hMenu As Long,  _
  ByVal wFlags As Long, ByVal wIDNewItem As Long, _
  ByVal lpNewItem As String) As Long
Declare Function EnableMenuItem Lib "user32" _
 (ByVal hMenu As Long, ByVal wIDEnableItem As Long, _
  ByVal wEnable As Long) As Long
Public Const MF_SEPARATOR = &H800&
Public Const MF_GRAYED = &H1&
Public Const MF_STRING = &H0&
Public Const WM_SYSCOMMAND = &H112
Public Const WM_INITMENUPOPUP = &H117

Public m_wndprcNext As Long
Public Const IDM_INCR As Long = 1000


Public Function WindowProc _
 (ByVal hWnd As Long, ByVal uMsg As Long, _
  ByVal wParam As Long, ByVal lParam As Long) As Long
    Dim hSysMenu As Long
    Static c As Integer

    Select Case uMsg
    Case WM_INITMENUPOPUP
      If lParam \ 65535 And &HFFFF& Then 'HIWORD of lparam
	hSysMenu = GetSystemMenu(hWnd, 0)
	If wParam = hSysMenu Then
	  EnableMenuItem  _
	   hSysMenu, IDM_INCR, ByVal IIf _
	  (Form1.WindowState = vbMinimized, MF_GRAYED, 0)
	End If
      End If
    Case WM_SYSCOMMAND
      Select Case wParam
      Case IDM_INCR
	c = c + 1
	Form1.lblCount.Caption = CStr(c) & "回目"
      End Select
    End Select
    WindowProc = CallWindowProc _
     (m_wndprcNext, hWnd, uMsg, wParam, ByVal lParam)
End Function