[RESOLVED] [VB6] - can i hide a control without using the ShowWindow() api function?

[joaquim]

can i hide a control without using the ShowWindow() api function?

[Peter Swinkels]

I assume you're already aware of the "Visible" property for Visual Basic controls. Here is some code that hides windows without using the ShowWindow API function:

Option Explicit

Private Const GWL_STYLE As Long = -16&
Private Const WS_VISIBLE As Long = &H10000000

Private Declare Function GetParent Lib "User32.dll" (ByVal hwnd As Long) As Long
Private Declare Function GetWindowLongA Lib "User32.dll" (ByVal hwnd As Long, ByVal nIndex As Long) As Long
Private Declare Function SetWindowLongA Lib "User32.dll" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Declare Function UpdateWindow Lib "User32.dll" (ByVal lhwnd As Long) As Long

Private Sub HideWindow(WindowH As Long)
Dim Styles As Long

Styles = GetWindowLongA(WindowH, GWL_STYLE)
SetWindowLongA WindowH, GWL_STYLE, (Styles Xor WS_VISIBLE)

RefreshWindow WindowH
End Sub

Public Sub Main()
Dim WindowH As Long

WindowH = CLng(Val(InputBox$("Window handle:", , "0")))
If WindowH = 0 Then Exit Sub

HideWindow WindowH
End Sub

Public Sub RefreshWindow(ByVal WindowH As Long)
Do
   UpdateWindow WindowH
   WindowH = GetParent(WindowH)
   DoEvents
Loop Until WindowH = 0
End Sub

People could help you better if you explained why you don't want to use the ShowWindow API function.

[joaquim]

I assume you're already aware of the "Visible" property for Visual Basic controls. Here some code that hides windows without using the ShowWindow API function:

Option Explicit

Private Const GWL_STYLE As Long = -16&
Private Const WS_VISIBLE As Long = &H10000000

Private Declare Function GetParent Lib "User32.dll" (ByVal hwnd As Long) As Long
Private Declare Function GetWindowLongA Lib "User32.dll" (ByVal hwnd As Long, ByVal nIndex As Long) As Long
Private Declare Function SetWindowLongA Lib "User32.dll" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Declare Function UpdateWindow Lib "User32.dll" (ByVal lhwnd As Long) As Long

Private Sub HideWindow(WindowH As Long)
Dim Styles As Long

Styles = GetWindowLongA(WindowH, GWL_STYLE)
SetWindowLongA WindowH, GWL_STYLE, (Styles Xor WS_VISIBLE)

RefreshWindow WindowH
End Sub

Public Sub Main()
Dim WindowH As Long

WindowH = CLng(Val(InputBox$("Window handle:", , "0")))
If WindowH = 0 Then Exit Sub

HideWindow WindowH
End Sub

Public Sub RefreshWindow(ByVal WindowH As Long)
Do
   UpdateWindow WindowH
   WindowH = GetParent(WindowH)
   DoEvents
Loop Until WindowH = 0
End Sub

People could help you better if you explained why you don't want to use the ShowWindow API function.

because isn't working in these case
i have another question that can go out of the topic, but i have another thread for that
thanks for all

[Bonnie West]

SetWindowPos can also hide/show a control:

Private Const SWP_NOSIZE     As Long = &H1  'Retains the current size (ignores the cx and cy parameters)
Private Const SWP_NOMOVE     As Long = &H2  'Retains the current position (ignores X and Y parameters)
Private Const SWP_NOZORDER   As Long = &H4  'Retains the current Z order (ignores the hWndInsertAfter parameter)
Private Const SWP_SHOWWINDOW As Long = &H40 'Displays the window
Private Const SWP_HIDEWINDOW As Long = &H80 'Hides the window

Private Declare Function SetWindowPos Lib "user32.dll" ( _
             ByVal hWnd As Long, _
    Optional ByVal hWndInsertAfter As Long, _
    Optional ByVal X As Long, Optional ByVal Y As Long, _
    Optional ByVal cx As Long, Optional ByVal cy As Long, _
    Optional ByVal uFlags As Long _
) As Long

Public Sub HideOrShowControl(ByRef Ctrl As Control, Optional ByVal Show As Boolean)
    Const SWP_FLAGS = SWP_NOSIZE Or SWP_NOMOVE Or SWP_NOZORDER

    On Error Resume Next
    If Show Then
        SetWindowPos Ctrl.hWnd, uFlags:=SWP_FLAGS Or SWP_SHOWWINDOW
    Else
        SetWindowPos Ctrl.hWnd, uFlags:=SWP_FLAGS Or SWP_HIDEWINDOW
    End If
End Sub

[joaquim]

SetWindowPos can also hide/show a control:

Private Const SWP_NOSIZE     As Long = &H1  'Retains the current size (ignores the cx and cy parameters)
Private Const SWP_NOMOVE     As Long = &H2  'Retains the current position (ignores X and Y parameters)
Private Const SWP_NOZORDER   As Long = &H4  'Retains the current Z order (ignores the hWndInsertAfter parameter)
Private Const SWP_SHOWWINDOW As Long = &H40 'Displays the window
Private Const SWP_HIDEWINDOW As Long = &H80 'Hides the window

Private Declare Function SetWindowPos Lib "user32.dll" ( _
             ByVal hWnd As Long, _
    Optional ByVal hWndInsertAfter As Long, _
    Optional ByVal X As Long, Optional ByVal Y As Long, _
    Optional ByVal cx As Long, Optional ByVal cy As Long, _
    Optional ByVal uFlags As Long _
) As Long

Public Sub HideOrShowControl(ByRef Ctrl As Control, Optional ByVal Show As Boolean)
    Const SWP_FLAGS = SWP_NOSIZE Or SWP_NOMOVE Or SWP_NOZORDER

    On Error Resume Next
    If Show Then
        SetWindowPos Ctrl.hWnd, uFlags:=SWP_FLAGS Or SWP_SHOWWINDOW
    Else
        SetWindowPos Ctrl.hWnd, uFlags:=SWP_FLAGS Or SWP_HIDEWINDOW
    End If
End Sub

thanks