How to activate, move and resize a window in VB.NET

Question

I have a window in which I only know the title (for example, Notepad), which I need to activate, resize and place in the upper left corner of the screen. So after some research on MSDN and forums, I found some features that should have accomplished this. I use FindWindow to get the descriptor for the title, then I use GetWindowPlacement to find out if the notepad is minimized or not (if not, then I just use AppActivate, I just need to activate it if it is not minimized). However, if the window is minimized, I then try to use SetWindowPlacement to activate, resize and move it in one command. Here is my code:

<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _ Private Shared Function FindWindow( _ ByVal lpClassName As String, _ ByVal lpWindowName As String) As IntPtr End Function <DllImport("user32.dll")> _ Private Shared Function GetWindowPlacement(ByVal hWnd As IntPtr, ByRef lpwndpl As WINDOWPLACEMENT) As Boolean End Function <DllImport("user32.dll")> _ Private Shared Function SetWindowPlacement(ByVal hWnd As IntPtr, ByRef lpwndpl As WINDOWPLACEMENT) As Boolean End Function Private Structure RECT Public Left As Integer Public Top As Integer Public Right As Integer Public Bottom As Integer Public Sub New(ByVal X As Integer, ByVal Y As Integer, ByVal X2 As Integer, ByVal Y2 As Integer) Me.Left = X Me.Top = Y Me.Right = X2 Me.Bottom = Y2 End Sub End Structure Private Structure WINDOWPLACEMENT Public Length As Integer Public flags As Integer Public showCmd As ShowWindowCommands Public ptMinPosition As POINTAPI Public ptMaxPosition As POINTAPI Public rcNormalPosition As RECT End Structure Enum ShowWindowCommands As Integer Hide = 0 Normal = 1 ShowMinimized = 2 Maximize = 3 ShowMaximized = 3 ShowNoActivate = 4 Show = 5 Minimize = 6 ShowMinNoActive = 7 ShowNA = 8 Restore = 9 ShowDefault = 10 ForceMinimize = 11 End Enum Public Structure POINTAPI Public X As Integer Public Y As Integer Public Sub New(ByVal X As Integer, ByVal Y As Integer) Me.X = X Me.Y = Y End Sub End Structure 

With actual execution here:

 Dim wp As WINDOWPLACEMENT wp.Length = Marshal.SizeOf(wp) GetWindowPlacement(FindWindow(Nothing, "Notepad"), wp) If wp.showCmd = ShowWindowCommands.ShowMinimized Then Dim wp2 As WINDOWPLACEMENT wp2.showCmd = ShowWindowCommands.ShowMaximized wp2.ptMinPosition = wp.ptMinPosition wp2.ptMaxPosition = New POINTAPI(0, 0) wp2.rcNormalPosition = New RECT(0, 0, 816, 639) 'this is the size I want wp2.flags = wp.flags wp2.Length = Marshal.SizeOf(wp2) SetWindowPlacement(FindWindow(Nothing, "Notepad"), wp2) Else AppActivate("Notepad") 

So, I'm trying to run this, but it just activates the window, while the rectangle should also resize it. So what am I doing wrong? Is there an easier way to achieve all this? Sorry for the long post.

Answer 1

I needed to do a similar thing and use the SetWindowPos function from user32.dll

Here's the vb.net implementation:

 Imports System Imports System.Runtime.InteropServices Imports System.Diagnostics Public Class HookUtil Public Const SWP_NOMOVE As Short = &H2 Public Const SWP_NOSIZE As Short = 1 Public Const SWP_NOZORDER As Short = &H4 Public Const SWP_SHOWWINDOW As Short = &H40 Shared ReadOnly HWND_BOTTOM As IntPtr = New IntPtr(1) <DllImport("user32.dll", EntryPoint:="SetWindowPos")> _ Public Shared Function SetWindowPos( _ hWnd As IntPtr, _ hWndInsertAfter As IntPtr, _ x As Int32, y As Int32, cx As Int32, cy As Int32, wFlags As Int32) As IntPtr End Function Public Shared Sub HookWindow() Dim Processes As Process() = Process.GetProcessesByName("Notepad") For Each p As Process In Processes Dim handle As IntPtr = p.MainWindowHandle If handle <> IntPtr.Zero Then SetWindowPos(handle, HWND_BOTTOM, 200, 200, 0, 0, SWP_NOZORDER Or SWP_NOSIZE Or SWP_SHOWWINDOW) End If Next End Sub End Class 

You call it with:

 HookUtil.HookWindow() 

Here's the C # implementation:

 using System; using System.Runtime.InteropServices; using System.Diagnostics; namespace csharpsandbox { public class HookUtil { // hooks window handle and repositions to specified coords [DllImport("user32.dll", EntryPoint = "SetWindowPos")] public static extern IntPtr SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int x, int Y, int cx, int cy, int wFlags); [DllImport("kernel32.dll")] static extern IntPtr LoadLibrary(string lpFileName); const short SWP_NOMOVE = 0X2; const short SWP_NOSIZE = 1; const short SWP_NOZORDER = 0X4; const int SWP_SHOWWINDOW = 0x0040; static readonly IntPtr HWND_BOTTOM = new IntPtr(1); public static void HookWindow() { Process[] parray = System.Diagnostics.Process.GetProcessesByName("Notepad"); foreach (Process p in parray) { IntPtr handle = p.MainWindowHandle; if (handle != IntPtr.Zero) { SetWindowPos(handle, HWND_BOTTOM, 200, 200, 0, 0, SWP_NOZORDER | SWP_NOSIZE | SWP_SHOWWINDOW); } } } } } 

You call it with:

 HookUtil.HookWindow(); 

Obviously, the values ​​here (process name, x, y coordinates) are hardcoded. To make this more useful, you would like to make them available.