Removing the Title bar of external application using c#

Question

My application starts up another external application.

I want to remove the title bar of this external application once it has started.

Is this feasible, and if so how would it be done?

Based on the comments I am using the working code below

//Finds a window by class name
[DllImport("USER32.DLL")]
public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

//Sets a window to be a child window of another window
[DllImport("USER32.DLL")]
public static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);

//Sets window attributes
[DllImport("USER32.DLL")]
public static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);

//Gets window attributes
[DllImport("USER32.DLL")]
public static extern int GetWindowLong(IntPtr hWnd, int nIndex);

[DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
static extern IntPtr FindWindowByCaption(IntPtr ZeroOnly, string lpWindowName);


//assorted constants needed
public static int GWL_STYLE = -16;
public static int WS_CHILD = 0x40000000; //child window
public static int WS_BORDER = 0x00800000; //window with border
public static int WS_DLGFRAME = 0x00400000; //window with double border but no title
public static int WS_CAPTION = WS_BORDER | WS_DLGFRAME; //window with a title bar

public void WindowsReStyle()
{
    Process[] Procs = Process.GetProcesses();
    foreach (Process proc in Procs)
    {
        if (proc.ProcessName.StartsWith("notepad"))
        {
            IntPtr pFoundWindow = proc.MainWindowHandle;
            int style = GetWindowLong(pFoundWindow, GWL_STYLE);
            SetWindowLong(pFoundWindow, GWL_STYLE, (style & ~WS_CAPTION));
        }
    }
}

Answer 1

Process[] processes = Process.GetProcessesByName("notepad");
IntPtr windowHandle = processes[0].MainWindowHandle;

const int GWL_STYLE = (-16); 
const UInt32 WS_VISIBLE = 0x10000000;
SetWindowLong(windowHandle, GWL_STYLE, (WS_VISIBLE));`

Answer 2

No need to inject anything, you can just modify the windows style bits as using the API, e.g. this works for Notepad, however YMMV depending on the app you're playing with.

//Get current style
lCurStyle = GetWindowLong(hwnd, GWL_STYLE)

//remove titlebar elements
lCurStyle = lCurStyle And Not WS_CAPTION
lCurStyle = lCurStyle And Not WS_SYSMENU
lCurStyle = lCurStyle And Not WS_THICKFRAME
lCurStyle = lCurStyle And Not WS_MINIMIZE
lCurStyle = lCurStyle And Not WS_MAXIMIZEBOX

//apply new style
SetWindowLong hwnd, GWL_STYLE, lCurStyle

//reapply a 3d border
lCurStyle = GetWindowLong(hwnd, GWL_EXSTYLE)

SetWindowLong hwnd, GWL_EXSTYLE, lCurStyle Or WS_EX_DLGMODALFRAME

//redraw
SetWindowPos hwnd, 0, 0, 0, 0, 0, SWP_NOMOVE Or SWP_NOSIZE Or SWP_FRAMECHANGED

Answer 3

Well, Alex never elaborated with the code, well at least it wasn't a plug-n-play solution, but still the main credit for this goes to him... It IS kind of buggy unless you use "SetParent" to put it in some kind of container(such as a form or panel) Just thought I would share the result.

Visual Basic:

Option Strict On
Public Class Form1
    Const WS_BORDER As Integer = 8388608
    Const WS_DLGFRAME As Integer = 4194304
    Const WS_CAPTION As Integer = WS_BORDER Or WS_DLGFRAME
    Const WS_SYSMENU As Integer = 524288
    Const WS_THICKFRAME As Integer = 262144
    Const WS_MINIMIZE As Integer = 536870912
    Const WS_MAXIMIZEBOX As Integer = 65536
    Const GWL_STYLE As Integer = -16&
    Const GWL_EXSTYLE As Integer = -20&
    Const WS_EX_DLGMODALFRAME As Integer = &H1L
    Const SWP_NOMOVE As Integer = &H2
    Const SWP_NOSIZE As Integer = &H1
    Const SWP_FRAMECHANGED As Integer = &H20
    Const MF_BYPOSITION As UInteger = &H400
    Const MF_REMOVE As UInteger = &H1000
    Declare Auto Function GetWindowLong Lib "user32.dll" (ByVal hWnd As IntPtr, ByVal nIndex As Integer) As Integer
    Declare Auto Function SetWindowLong Lib "user32.dll" (ByVal hWnd As IntPtr, ByVal nIndex As Integer, ByVal dwNewLong As Integer) As Integer
    Declare Auto Function SetWindowPos Lib "user32.dll" (ByVal hWnd As IntPtr, ByVal hWndInsertAfter As IntPtr, ByVal X As Integer, ByVal Y As Integer, ByVal cx As Integer, ByVal cy As Integer, ByVal uFlags As Integer) As Boolean
    Public Sub MakeExternalWindowBorderless(ByVal MainWindowHandle As IntPtr)
        Dim Style As Integer
        Style = GetWindowLong(MainWindowHandle, GWL_STYLE)
        Style = Style And Not WS_CAPTION
        Style = Style And Not WS_SYSMENU
        Style = Style And Not WS_THICKFRAME
        Style = Style And Not WS_MINIMIZE
        Style = Style And Not WS_MAXIMIZEBOX
        SetWindowLong(MainWindowHandle, GWL_STYLE, Style)
        Style = GetWindowLong(MainWindowHandle, GWL_EXSTYLE)
        SetWindowLong(MainWindowHandle, GWL_EXSTYLE, Style Or WS_EX_DLGMODALFRAME)
        SetWindowPos(MainWindowHandle, New IntPtr(0), 0, 0, 0, 0, SWP_NOMOVE Or SWP_NOSIZE Or SWP_FRAMECHANGED)
    End Sub
End Class

C Sharp(C#)

using System.Runtime.InteropServices;
public class Form1
{
    const int WS_BORDER = 8388608;
    const int WS_DLGFRAME = 4194304;
    const int WS_CAPTION = WS_BORDER | WS_DLGFRAME;
    const int WS_SYSMENU = 524288;
    const int WS_THICKFRAME = 262144;
    const int WS_MINIMIZE = 536870912;
    const int WS_MAXIMIZEBOX = 65536;
    const int GWL_STYLE = -16L;
    const int GWL_EXSTYLE = -20L;
    const int WS_EX_DLGMODALFRAME = 0x1L;
    const int SWP_NOMOVE = 0x2;
    const int SWP_NOSIZE = 0x1;
    const int SWP_FRAMECHANGED = 0x20;
    const uint MF_BYPOSITION = 0x400;
    const uint MF_REMOVE = 0x1000;
    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true, ExactSpelling = true)]
    public static extern int GetWindowLong(IntPtr hWnd, int nIndex);
    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true, ExactSpelling = true)]
    public static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);
    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true, ExactSpelling = true)]
    public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, int uFlags);
    public void MakeExternalWindowBorderless(IntPtr MainWindowHandle)
    {
        int Style = 0;
        Style = GetWindowLong(MainWindowHandle, GWL_STYLE);
        Style = Style & ~WS_CAPTION;
        Style = Style & ~WS_SYSMENU;
        Style = Style & ~WS_THICKFRAME;
        Style = Style & ~WS_MINIMIZE;
        Style = Style & ~WS_MAXIMIZEBOX;
        SetWindowLong(MainWindowHandle, GWL_STYLE, Style);
        Style = GetWindowLong(MainWindowHandle, GWL_EXSTYLE);
        SetWindowLong(MainWindowHandle, GWL_EXSTYLE, Style | WS_EX_DLGMODALFRAME);
        SetWindowPos(MainWindowHandle, new IntPtr(0), 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_FRAMECHANGED);
    }
}

Again, Thank you Alex