Introduction
GetWindowPlacement
, SetWindowPlacement
, and FindWindow
: using these API functions, we can minimize or maximize or restore a window.
Using the functions
GetWindowPlacement
The GetWindowPlacement
function retrieves the show state and the restored, minimized, and maximized positions of the specified window.
GetWindowPlacement (ByVal hwnd As Integer, ByRef lpwndpl As WINDOWPLACEMENT) As Integer
SetWindowPlacement
The SetWindowPlacement
function sets the show state and the restored, minimized, and maximized positions of the specified window.
SetWindowPlacement (ByVal hwnd As Integer, ByRef lpwndpl As WINDOWPLACEMENT) As Integer
FindWindow
The FindWindow
function retrieves a handle to the top-level window whose class name and window name matches the specified strings. This function does not search child windows. This function does not perform a case-sensitive search.
FindWindow(string lpClassName,string lpWindowName)
Usage
Public Class Minimize
Private Declare Function FindWindow Lib "user32" Alias _
"FindWindowA" (ByVal lpClassName As String, _
ByVal lpWindowName As String) As Integer
Private Declare Function GetWindowPlacement Lib _
"user32" (ByVal hwnd As Integer, _
ByRef lpwndpl As WINDOWPLACEMENT) As Integer
Private Declare Function SetWindowPlacement Lib "user32" _
(ByVal hwnd As Integer, ByRef lpwndpl As WINDOWPLACEMENT) As Integer
Private Const SW_SHOWMINIMIZED As Short = 2
Private Const SW_SHOWMAXIMIZED As Short = 3
Private Const SW_SHOWNORMAL As Short = 1
Private Structure POINTAPI
Dim X As Integer
Dim Y As Integer
End Structure
Private Structure RECT
Dim Left_Renamed As Integer
Dim Top_Renamed As Integer
Dim Right_Renamed As Integer
Dim Bottom_Renamed As Integer
End Structure
Private Structure WINDOWPLACEMENT
Dim length As Integer
Dim flags As Integer
Dim showCmd As Integer
Dim ptMinPosition As POINTAPI
Dim ptMaxPosition As POINTAPI
Dim rcNormalPosition As RECT
End Structure
Public Sub windowAction(ByVal classname As String, ByVal action As String)
Dim app_hwnd As Integer
Dim wp As WINDOWPLACEMENT
app_hwnd = FindWindow(classname, vbNullString)
wp.length = Len(wp)
GetWindowPlacement(app_hwnd, wp)
Select Case action
Case "Minimize"
wp.showCmd = SW_SHOWMINIMIZED
Case "Maximize"
wp.showCmd = SW_SHOWMAXIMIZED
Case "Restore"
wp.showCmd = SW_SHOWNORMAL
End Select
SetWindowPlacement(app_hwnd, wp)
End Sub
End Class
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click
Dim test As New Minimize
test.windowAction("Notepad", "Minimize")
End Sub