Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Integer
    Declare Function SetWindowPos Lib "user32" (ByVal hwnd As Integer, ByVal hWndInsertAfter As Integer, ByVal x As Integer, ByVal y As Integer, ByVal cx As Integer, ByVal cy As Integer, ByVal wFlags As Integer) As Integer
 
 Const TASKBAR_SHOW As Integer = &H40
 Const TASKBAR_HIDE As Integer = &H80
 

Public Sub CacherBarreTacheWindows()
        Dim TaskbarHandle As Long
         TaskbarHandle = FindWindow("Shell_traywnd", "")
        SetWindowPos(TaskbarHandle, 0&, 0&, 0&, 0&, 0&, TASKBAR_HIDE)
End Sub
 

Public Sub MontrerBarreTacheWindows()
        Dim TaskbarHandle As Long
         TaskbarHandle = FindWindow("Shell_traywnd", "")
        SetWindowPos(TaskbarHandle, 0&, 0&, 0&, 0&, 0&,TASKBAR_SHOW)
End Sub

Private Const SWP_HIDEWINDOW As Long = &H80
Private Const SWP_SHOWWINDOW As Long = &H40
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function SetWindowPos Lib "user32" (ByVal hwnd As Long, ByVal hWndInsertAfter As Long, ByVal x As  Long, ByVal y As Long,  ByVal cx As Long, ByVal cy As  Long, ByVal wFlags As Long) As Long
'
'
Sub TaskBarShowHide(ByVal bShow As Boolean)
    Dim lRet As Long
    lRet = FindWindow("Shell_traywnd", vbNullString)
    If lRet Then Call SetWindowPos(lRet, 0&, 0&,  0&, 0&, 0&, IIf(bShow, SWP_SHOWWINDOW,  SWP_HIDEWINDOW))
End Sub

[DllImport("user32", EntryPoint = "FindWindowA")] 
public static extern int FindWindows(String lpClassName, String lpWindowsName);
[DllImport("user32")] 
public static extern int SetWindowPos(int hwnd, int hWndInsertAfter, int x, int y, int cx, int cy, int wFlags);


public const int TASKBAR_SHOW = 64; 
public const int TASKBAR_HIDE = 128;


public static void ShowBar() 
{
   int taskBarHandle = FindWindows("Shell_traywnd", String.Empty); 
   SetWindowPos(taskBarHandle, 0, 0, 0, 0, 0, TASKBAR_SHOW);
}

public static void HideBar() 
{
   int taskBarHandle = FindWindows("Shell_traywnd", String.Empty); 
   SetWindowPos(taskBarHandle, 0, 0, 0, 0, 0, TASKBAR_HIDE);
}