Mdi form

Private Declare Function ShowWindow Lib "user32" _
    (ByVal hwnd As Long, ByVal nCmdShow As Long) As Long
    
Private Declare Function FindWindow Lib "user32" _
    Alias "FindWindowA" (ByVal lpClassName As String, _
    ByVal lpWindowName As String) As Long
    
Private Declare Function FindWindowEx Lib "user32" _
    Alias "FindWindowExA" (ByVal hWnd1 As Long, _
    ByVal hWnd2 As Long, _
    ByVal lpsz1 As String, _
    ByVal lpsz2 As String) As Long

Sub TaskBar(blnValue As Boolean)
    Dim lngHandle As Long
    Dim lngStartButton As Long

    lngHandle = FindWindow("Shell_TrayWnd", "")
    
    If blnValue Then
        ShowWindow lngHandle, 5
    Else
        ShowWindow lngHandle, 0
    End If
End Sub

Private Declare Function SHAppBarMessage Lib "shell32" (ByVal dwMessage As Long, pData As APPBARDATA) As Long

Private Const ABM_GETSTATE = &H4
Private Const ABM_SETSTATE = &HA
Private Const ABS_AUTOHIDE = &H1
Private Const ABS_ALWAYSONTOP = &H2

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

Private Type APPBARDATA
cbSize As Long
hwnd As Long
uCallbackMessage As Long
uEdge As Long
rc As RECT
lParam As Long
End Type

Sub TaskbarAutohideOn()
Dim ABD As APPBARDATA
ABD.cbSize = Len(ABD)
SHAppBarMessage ABM_GETSTATE, ABD
ABD.lParam = ABS_AUTOHIDE
SHAppBarMessage ABM_SETSTATE, ABD
End Sub

Sub TaskbarAutohideOff()
Dim ABD As APPBARDATA
ABD.cbSize = Len(ABD)
SHAppBarMessage ABM_GETSTATE, ABD
ABD.lParam = ABS_ALWAYSONTOP
SHAppBarMessage ABM_SETSTATE, ABD
End Sub

Private Sub Command1_Click()
TaskbarAutohideOn
End Sub

Private Sub Command2_Click()
TaskbarAutohideOff
End Sub