How do I get the handle of a console application's window

Question

Can someone tell me how to get the handle of a Windows console application in C#? In a Windows Forms application, I would normally try this.Handle.

Cusick

Answer 1

Not sure it works, but you can try that :

IntPtr handle = Process.GetCurrentProcess().MainWindowHandle;

Donoho

For anyone else looking 2-22 years later; yes, this did work (for me). – Mogador

this appears to only work if your process started the console. if you run it from another console, you always get zero. it looks like you need to use findwindowbycaption in other situations (see support.microsoft.com/kb/124103) – Mycobacterium

This worked for me when debugging in Visual Studio, but when I ran without debugging it didn't. Double clocking the myProgram.exe in bin/Release did work, but FindWindowByCaption might be the more robust solution. – Lovesome

Earlier I always had much respect for this window and I never though I could manipulate it via code but it is a simple window that is not much different than others. The line above works and you can also enumerate and find it via WinApi and do all kinds of crazy stuff to it. Just be careful it has a WndProc that makes it resize a little differently. – Giagiacamo

Answer 2

• The aforementioned Process.MainWindowHandle method only works for the process that started the console
• The FindWindowByCaption method is inherently unreliable

Here's a robust way to do this:

The related functions from the Console Win32 API are:

[DllImport("kernel32.dll", SetLastError = true)]
static extern bool AttachConsole(uint dwProcessId);
[DllImport("kernel32.dll")]
static extern IntPtr GetConsoleWindow();
[DllImport("kernel32.dll", SetLastError=true, ExactSpelling=true)]
static extern bool FreeConsole();

• For the console the current process is attached to, just GetConsoleWindow() is enough
• For the console another process is attached to, attach to it as well with AttachConsole, call GetConsoleWindow, them immediately detach with FreeConsole.

For the extra cautious, register a console event handler before attaching (and unregister it after detaching) as well so you don't accidentally get terminated if a console event happens in the tiny time frame you're attached to the console:

[DllImport("kernel32.dll")]
static extern bool SetConsoleCtrlHandler(ConsoleCtrlDelegate HandlerRoutine,
   bool Add);
delegate Boolean ConsoleCtrlDelegate(CtrlTypes CtrlType);
enum CtrlTypes : uint {
    CTRL_C_EVENT = 0,
    CTRL_BREAK_EVENT,
    CTRL_CLOSE_EVENT,  
    CTRL_LOGOFF_EVENT = 5,
    CTRL_SHUTDOWN_EVENT
}

bool is_attached=false;    
ConsoleCtrlDelegate ConsoleCtrlDelegateDetach = delegate(CtrlType) {
     if (is_attached = !FreeConsole())
         Trace.Error('FreeConsole on ' + CtrlType + ': ' + new Win32Exception());
     return true;
};

---

Making changes to the current process just to read something is rather ugly (when this is a console process, this gets really ugly since it requires a helper process to avoid terminating the current console). Nevertheless, further investigation shows that there's no other way short of injecting into the csrss process or the target process.

Console correspondence information is located in and managed by csrss.exe (or a multitude of those, one for each session, since Vista), so it can't be retrieved with the likes of ReadProcessMemory. All that csrss exposes is the CSRSS LPC API. There's only one relevant function in the full API list, SrvGetConsoleWindow. And it doesn't accept a PID but determines that of the calling party as seen in an alternative implementation or the function's disassembly in winsrv.dll.

Alphitomancy

This should be the accepted answer. GetConsoleWindow is the right way to do this; many of the other answers here are just plain goofy. – Filemon

This is the correct answer IMHO, unless you want to spend time figuring out why your application doesn't work when you run it from the console as opposed to the IDE. Thanks Ivan. – Nanete

Please note that the official MS documentation says that GetConsoleWindow() is semi-deprecated and, while it will be supported, it is NOT recommended for new code. – Anyplace

@Anyplace Reading the MSDN article on GetConsoleWindow, that's not actually what they call "deprecation" -- they aren't removing it anytime in the future. They rather suggest to move to using terminal control sequences -- which don't require getting the console's window handle at all. So this fact is not very relevant to the current question. – Alphitomancy

Answer 3

Try this:

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

Console.Title = "Test";
…

IntPtr handle = FindWindowByCaption(IntPtr.Zero, Console.Title);

Invaginate

Answer 4

I've just solved this problem for myself (unfortunately before seeing Thomas's answer which is much quicker). Well, here's another way for those who are not satisfied with his answer. I'm writing this answer because I want to provide another answer + a better way to design the Program class if you're treating your console as a Window. Let's begin with that design:

I've kind of changed the default style of the Program class. I've actually made it into a class that has a program in it, and not just one method which represent it and uses other classes for content. (If you don't know what I mean, not important).

The reason I had to do it is because I wanted to write the following event handler:

private void CatchUnhandled(Object sender, UnhandledExceptionEventArgs e)
{
    var exception = e.ExceptionObject as Exception;
    MessageBox.Show(this, exception.Message, "Error"); // Check out 1st arg.
}

It overloads this method MessageBox.Show(IWin32Window, String, String).

Because Console doesn't implement IWin32Window, I had to implement it myself, of course, in order to just call this in the 1^st argument.

Here is the implementation of it and everything else:

Note: this code is copy-pasted from my application, you can feel free to change the access modifiers

Program Class Declaration:

internal class Program : IWin32Window
{
    ...
}

IWin32Window Implementation:

public IntPtr Handle
{
    get { return NativeMethods.GetConsoleWindow(); }
}

It uses the following class:

internal static class NativeMethods
{
    [DllImport("kernel32.dll")]
    internal static extern IntPtr GetConsoleWindow();
}

Now, the problem is that you can't actually call this in Main, being a static method, so whatever was in Main I've moved to a new method named Start and all Main is doing is creating a new Program and calling Start.

private static void Main()
{
    new Program().Start();
}

private void Start()
{
    AppDomain.CurrentDomain.UnhandledException += CatchUnhandled;

    throw new Exception();
}

The result was, of course, a message-box with my console's window as an owner.
Using this method for a message-box, is of course only one application of this method.

Compound

In short the answer is: [DllImport("kernel32.dll")] internal static extern IntPtr GetConsoleWindow(); – Conventioneer

Answer 5

I don't think there is such a thing. The console window is not accessible to the application. You MIGHT try to iterate the process list looking for your own process name. The Process class IIRC contains a property for the program's main window handle, which might be the console window for console applications - which I'm not sure of.

Nepenthe

"iterate the process list looking for your own process name" => not a very efficient approach... you could find it by the PID, or use } ;) – Donoho

Whoops - Thomas Levesque's answer is even more elegant. While relying on the same property, he doesn't need to iterate. I forgot that you can access to current process directly... – Nepenthe

@Thomas: Sorry, didn't see your comment before. Of course, iterating is far more inefficient. I didn't remember the GetCurrentProcess() method... – Nepenthe

Answer 6

One more version in VB.Net on how to show MessageBox on top of console window

Imports System.Runtime.InteropServices
Imports System.Windows.Forms

Friend Module NativeMethods
    <DllImport("kernel32.dll")> Friend Function GetConsoleWindow() As IntPtr
    End Function
End Module

NotInheritable Class WndProxy
    Implements IWin32Window
    ReadOnly Property Handle As IntPtr Implements IWin32Window.Handle
    Sub New(_hwnd As IntPtr)
        Handle = _hwnd
    End Sub
End Class

Module Module1

    Sub Main()
        ' using MainWindowHandle
        Dim w = New WndProxy(Process.GetCurrentProcess().MainWindowHandle)
        MessageBox.Show(w, "Hi")
        ' using GetConsoleWindow api
        Dim s = New WndProxy(NativeMethods.GetConsoleWindow)
        MessageBox.Show(s, "Hi")
    End Sub

End Module

Iguanodon