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How to start a process from a Windows Forms (C#) without creating a taskbar icon

I have a Windows Forms application with a button that's supposed to open an exe file.
The default Windows behavior is that the exe file, once opened, will have its own icon appear in the taskbar, however the requirement is for it not to have the icon, and for the window to appear "nested" inside the icon of the Windows Form application from which it originates, so to hide the location of the exe file from users.
I have looked around for a solution, and my understanding is that in order to achieve this, I would have to use the user32.dll library.
I have found some code online that attempts something similar (no window, no taskbar icon), and I am trying to tweak it so that it fits my needs, but so far I am stuck.
This is what I have:
private int GWL_STYLE = -16;
private int GWL_EXSTYLE = -20;
private int WS_EX_APPWINDOW = 262144;
private UInt32 WS_POPUP = 0x80000000;
private UInt32 WS_CHILD = 0x40000000;
[DllImport("user32.dll")]
private static extern int GetWindowLong(IntPtr hWnd, int nIndex);
[DllImport("user32.dll")]
private static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);
[DllImport("user32.dll", SetLastError = true)]
private static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);
public Process HideProcess(string executablesPath, System.Windows.Forms.Form parentForm) {
Process valueToReturn = null;
if (executablesPath != null && executablesPath.Equals(String.Empty) == false && File.Exists(executablesPath) == true) {
ProcessStartInfo startInfo = new ProcessStartInfo(executablesPath);
startInfo.WindowStyle = ProcessWindowStyle.Hidden;
valueToReturn = Process.Start(startInfo);
int style = GetWindowLong(valueToReturn.MainWindowHandle, GWL_EXSTYLE) & ~WS_EX_APPWINDOW;
SetWindowLong(valueToReturn.MainWindowHandle, GWL_EXSTYLE, style);
SetParent(valueToReturn.MainWindowHandle, parentForm.Handle);
}
return valueToReturn;
}
I have tried several different variations of this method, but I always get close but not exactly where I'd like to be.
The documentation I have found seems a little bit confusing, so I am a little bit stuck and would appreciate some help.

How to get / set Unity Editor main window title?

I'm creating a tool that shows your current branch in Unity window title.
But I cannot get or set the title. So far I managed to set title property, I used Internal_SetTitle (using Reflection), but the values does not show up in the actual window title.
On the contrary, I can set position property of main window just fine using the same method.
Did anybody manage to alter the title using UnityEditor classes?
(Probably I could work the issue around by creating native plugins for that, but I'd prefer a cross-platform / Mono solution if there is any)

I know this isn't quite what you're after but could complement your solution, or help others in a similar situation, here is Windows only PInvoke approach to get the window handle and title of that window, associated with your current thread.
You could add use of the SetWindowText WinAPI as well to set the title, although you may need to do this whenever there is a configuration change as you've mentioned.
[DllImport("user32.dll")]
private static extern bool EnumWindows(EnumWindowsProc lpEnumFunc, IntPtr lParam);
[DllImport("user32.dll", SetLastError = true)]
private static extern uint GetWindowThreadProcessId(IntPtr hWnd, out uint lpdwProcessId);
[DllImport("user32.dll", EntryPoint = "GetWindowText")]
private static extern int GetWindowText(IntPtr hWnd, StringBuilder lpWindowText, int nMaxCount);
delegate bool EnumWindowsProc(IntPtr hWnd, IntPtr lParam);
private static string GetUnityEditorWindowName()
{
var processId = (uint)Process.GetCurrentProcess().Id;
var windowHandle = IntPtr.Zero;
string result = "";
EnumWindows((hWnd, lParam) =>
{
GetWindowThreadProcessId(hWnd, out var windowProcessId);
if (windowProcessId != processId)
return true;
var titleBuilder = new StringBuilder(256);
GetWindowText(hWnd, titleBuilder, titleBuilder.Capacity);
if (titleBuilder.Length <= 0)
return true;
result = titleBuilder.ToString();
windowHandle = hWnd;
return false;
}, IntPtr.Zero);
if (windowHandle == IntPtr.Zero)
{
Debug.LogError("Failed to find Unity Editor Window");
}
return result;
}

Send text to another process in C# [duplicate]

Using Winspector I've found out the ID of the child textbox I want to change is 114. Why isn't this code changing the text of the TextBox?
[DllImport("user32.dll")]
static extern IntPtr GetDlgItem(IntPtr hDlg, int nIDDlgItem);
[DllImport("user32.dll")]
public static extern int SendMessage(IntPtr hWnd, int msg, int Param, string s);
const int WM_SETTEXT = 0x000c;
private void SetTextt(IntPtr hWnd, string text)
{
IntPtr boxHwnd = GetDlgItem(hWnd, 114);
SendMessage(boxHwnd, WM_SETTEXT, 0, text);
}

The following is what I've used successfully for that purpose w/ my GetLastError error checking removed/disabled:
[DllImport("user32.dll", SetLastError = false)]
public static extern IntPtr GetDlgItem(IntPtr hDlg, int nIDDlgItem);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
public static extern IntPtr SendMessage(HandleRef hWnd, uint Msg, IntPtr wParam, string lParam);
public const uint WM_SETTEXT = 0x000C;
private void InteropSetText(IntPtr iptrHWndDialog, int iControlID, string strTextToSet)
{
IntPtr iptrHWndControl = GetDlgItem(iptrHWndDialog, iControlID);
HandleRef hrefHWndTarget = new HandleRef(null, iptrHWndControl);
SendMessage(hrefHWndTarget, WM_SETTEXT, IntPtr.Zero, strTextToSet);
}
I've tested this code and it works, so if it fails for you, you need to be sure that you are using the right window handle (the handle of the Dialog box itself) and the right control ID. Also try something simple like editing the Find dialog in Notepad.
I can't comment yet in the post regarding using (char *) but it's not necessary. See the second C# overload in p/Invoke SendMessage. You can pass String or StringBuilder directly into SendMessage.
I additionally note that you say that your control ID is 114. Are you certain WinSpector gave you that value in base 10? Because you are feeding it to GetDlgItem as a base 10 number. I use Spy++ for this and it returns control IDs in base 16. In that case you would use:
IntPtr boxHwnd = GetDlgItem(hWnd, 0x0114);

Please convert your control id (obtained from spy ++) from Hexdecimal Number to Decimal Number and pass that value to the GetDlgItem function.With this
you will get the handle of Text box.This worked for me.
[DllImport("user32.dll")]
static extern IntPtr GetDlgItem(IntPtr hDlg, int nIDDlgItem);
[DllImport("user32.dll")]
public static extern int SendMessage(IntPtr hWnd, int msg, int Param, string s);
const int WM_SETTEXT = 0x000c;
private void SetTextt(IntPtr hWnd, string text)
{
IntPtr boxHwnd = GetDlgItem(hWnd, 114);
SendMessage(boxHwnd, WM_SETTEXT, 0, text);
}

Are you sure you are passing text right? SendMessage last param should be a pointer to char* containing text you want to set.
Look at my "crude hack" of setting text in
How to get selected cells from TDBGrid in Delphi 5
this is done in Delphi 5, where PChar is char* alias, and I simply cast it as int (Integer in Delphi).

You must make sure that "text" is allocated in the external app's memory space. You will not be able to allocate text in the caller app and pass it to another app as each of them will have their own private memory space.

How do I scrape controls on an Windows Forms application which doesn't have an handle?

I have a Windows application. Where can I find the handle of the window?
I am unable to find the handle of the controls placed within that window. How can I scrape such controls? If it's a textbox or a button, I can automate it using the move position and send message. How does this work with a data grid/ table?

You have to go to the Win32 API for that.
Import EnumChildWindows like this:
[DllImport("user32.dll")]
private static extern bool EnumChildWindows(Intptr parent, EnumWindowsProc enumProc, IntPtr lParam);
public delegate bool EnumWindowsProc(IntPtr hWnd, IntPtr lParam);
And then call it from you main windows with this.Handle as the parent's windows handle. It will call the delegate for every child control in the form. This will show a messagebox for every control in the window:
[System.Runtime.InteropServices.DllImport("user32.dll", CharSet = System.Runtime.InteropServices.CharSet.Auto, SetLastError = true)]
private static extern int GetWindowText(IntPtr hWnd, System.Text.StringBuilder lpString, int nMaxCount);
[System.Runtime.InteropServices.DllImport("user32.dll", SetLastError = true, CharSet = System.Runtime.InteropServices.CharSet.Auto)]
static extern int GetWindowTextLength(IntPtr hWnd);
EnumChildWindows(this.Handle, (handle, b) => {
int length = GetWindowTextLength(handle);
System.Text.StringBuilder sb = new System.Text.StringBuilder(length + 1);
GetWindowText(handle, sb, sb.Capacity);
MessageBox.Show(sb.ToString()); return true;
}, IntPtr.Zero);

Detecting a modal dialog box of another process

I want to detect whether another process say process.exe is currently displaying a dialog box ?
Is there a way to do that in C# ?
To see if I could get the handle of the dialog box. I have tried Spy++ 's find window tool, when I try to drag the finder on top of the dialog box, it does not highlight the dialogbox but populates the details and
mentions AppCustomDialogBox and mentions the handle number
Please advise how can I programatically detect that ..
Thanks,

When an application shows a dialog box, the (for me quietly annoying) behaviour of Windows Operating System is to show the newly created window on top of all other. So if I assume that You know which process to watch, a way to detect a new window is to set up a windows hook:
delegate void WinEventDelegate(IntPtr hWinEventHook, uint eventType,
IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime);
[DllImport("user32.dll")]
public static extern IntPtr SetWinEventHook(uint eventMin, uint eventMax, IntPtr
hmodWinEventProc, WinEventDelegate lpfnWinEventProc, uint idProcess,
uint idThread, uint dwFlags);
[DllImport("user32.dll")]
public static extern bool UnhookWinEvent(IntPtr hWinEventHook);
// Constants from winuser.h
public const uint EVENT_SYSTEM_FOREGROUND = 3;
public const uint WINEVENT_OUTOFCONTEXT = 0;
//The GetForegroundWindow function returns a handle to the foreground window.
[DllImport("user32.dll")]
public static extern IntPtr GetForegroundWindow();
// For example, in Main() function
// Listen for foreground window changes across all processes/threads on current desktop
IntPtr hhook = SetWinEventHook(EVENT_SYSTEM_FOREGROUND, EVENT_SYSTEM_FOREGROUND, IntPtr.Zero,
new WinEventDelegate(WinEventProc), 0, 0, WINEVENT_OUTOFCONTEXT);
void WinEventProc(IntPtr hWinEventHook, uint eventType,
IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
{
IntPtr foregroundWinHandle = GetForegroundWindow();
//Do something (f.e check if that is the needed window)
}
//When you Close Your application, remove the hook:
UnhookWinEvent(hhook);
I did not try that code explicitely for dialog boxes, but for separate processes it works well. Please remember that that code cannot work in a windows service or a console application as it requires a message pump (Windows applications have that). You'll have to create an own.
Hope this helps

As modal dialogs normally disable the parent window(s), you can enumerate all top level windows for a process and see if they're enabled using the IsWindowEnabled() function.