Comments on: Console Output from a WinForms Application

By: AGreenhill

AGreenhill — Fri, 16 Jul 2010 18:23:30 +0000

Perfect – just what I needed! (I don't mind the dumping to txt file issue)

By: Ray

Ray — Thu, 25 Feb 2010 09:53:39 +0000

Just an FYI, this may not be a huge concern, I've noticed that when ran from a batch file, this solution works well which was the point of me adding cmd line functionality, so I'm happy, although obviously I still want "perfect"

By: Shmulik

Shmulik — Wed, 17 Feb 2010 19:22:23 +0000

Hi all,
I have developed a C# Windows application and I need to add command line support for it. Using the AttachConsole method I succeeded to output messages from the application to the console window that launched the application.
The problem is that the console also prints the user prompt ("C:\[path]>") before the apllication messages are printed.
Is there any way to avoid printing the user prompt? I just want to output my messages from the Windows application directly to the cursor location.

By: spottedcoin

spottedcoin — Thu, 28 Jan 2010 20:33:35 +0000

If you attach the Standard input with the output and error then you won't have to use the sendkeys command and it will fix the issue with not grabbing the attention of the entire console. I edited the code posted above to the following:
[DllImport("kernel32.dll")]
static extern bool AttachConsole(UInt32 dwProcessId);
[DllImport("kernel32.dll")]
static extern bool FreeConsole();
[DllImport("kernel32.dll")]
static extern bool AllocConsole();
[DllImport("kernel32.dll")]
private static extern bool GetFileInformationByHandle(SafeFileHandle hFile, out BY_HANDLE_FILE_INFORMATION lpFileInformation);
[DllImport("kernel32.dll")]
private static extern SafeFileHandle GetStdHandle(UInt32 nStdHandle);
[DllImport("kernel32.dll")]
private static extern bool SetStdHandle(UInt32 nStdHandle, SafeFileHandle hHandle);
[DllImport("kernel32.dll")]
private static extern bool DuplicateHandle(IntPtr hSourceProcessHandle, SafeFileHandle hSourceHandle, IntPtr hTargetProcessHandle,
out SafeFileHandle lpTargetHandle, UInt32 dwDesiredAccess, Boolean bInheritHandle, UInt32 dwOptions);

private const UInt32 ATTACH_PARENT_PROCESS = 0xFFFFFFFF;
private const UInt32 STD_INPUT_HANDLE = 0xFFFFFFF6;
private const UInt32 STD_OUTPUT_HANDLE = 0xFFFFFFF5;
private const UInt32 STD_ERROR_HANDLE = 0xFFFFFFF4;
private const UInt32 DUPLICATE_SAME_ACCESS = 2;

static SafeFileHandle hStdIn, hStdOut, hStdErr, hStdOutDup, hStdErrDup, hStdInDup;
static BY_HANDLE_FILE_INFORMATION bhfi;

private struct BY_HANDLE_FILE_INFORMATION
{
public UInt32 FileAttributes;
public System.Runtime.InteropServices.ComTypes.FILETIME CreationTime;
public System.Runtime.InteropServices.ComTypes.FILETIME LastAccessTime;
public System.Runtime.InteropServices.ComTypes.FILETIME LastWriteTime;
public UInt32 VolumeSerialNumber;
public UInt32 FileSizeHigh;
public UInt32 FileSizeLow;
public UInt32 NumberOfLinks;
public UInt32 FileIndexHigh;
public UInt32 FileIndexLow;
}

private static void InitConsoleHandles()
{
hStdIn = GetStdHandle(STD_INPUT_HANDLE);
hStdOut = GetStdHandle(STD_OUTPUT_HANDLE);
hStdErr = GetStdHandle(STD_ERROR_HANDLE);

// Get current process handle
IntPtr hProcess = Process.GetCurrentProcess().Handle;

// Duplicate Stdout handle to save initial value
DuplicateHandle(hProcess, hStdIn, hProcess, out hStdInDup, 0, true, DUPLICATE_SAME_ACCESS);

// Duplicate Stdout handle to save initial value
DuplicateHandle(hProcess, hStdOut, hProcess, out hStdOutDup, 0, true, DUPLICATE_SAME_ACCESS);

// Duplicate Stderr handle to save initial value
DuplicateHandle(hProcess, hStdErr, hProcess, out hStdErrDup, 0, true, DUPLICATE_SAME_ACCESS);

// Attach to console window – this may modify the standard handles
AttachConsole(ATTACH_PARENT_PROCESS);
//AllocConsole();

// Adjust the standard handles
if (GetFileInformationByHandle(GetStdHandle(STD_INPUT_HANDLE), out bhfi))
{
SetStdHandle(STD_INPUT_HANDLE, hStdInDup);
}
else
{
SetStdHandle(STD_INPUT_HANDLE, hStdIn);
}

if (GetFileInformationByHandle(GetStdHandle(STD_OUTPUT_HANDLE), out bhfi))
{
SetStdHandle(STD_OUTPUT_HANDLE, hStdOutDup);
}
else
{
SetStdHandle(STD_OUTPUT_HANDLE, hStdOut);
}

if (GetFileInformationByHandle(GetStdHandle(STD_ERROR_HANDLE), out bhfi))
{
SetStdHandle(STD_ERROR_HANDLE, hStdErrDup);
}
else
{
SetStdHandle(STD_ERROR_HANDLE, hStdErr);
}
}

private static void ReleaseConsoleHandles()
{
FreeConsole();
}

By: Rocky

Rocky — Thu, 07 Jan 2010 10:29:26 +0000

Jonathan,

You are simply a genius da!!!!

By: R. Whitfield

R. Whitfield — Mon, 07 Dec 2009 21:36:45 +0000

This seems to work well for my needs. Greatly appreciated.

By: Jonathan Counihan

Jonathan Counihan — Wed, 04 Nov 2009 06:30:17 +0000

Hi Crayon, Thanks, I tried putting GetConsoleTitle after the AttachConsole call, but no luck so far, still the same error.

I'll keep looking for an answer and post it here if I find one.

Cheers.

By: Crayon

Crayon — Tue, 03 Nov 2009 16:47:53 +0000

Jonathan, in my code I'm calling GetConsoleTitle after
AttachConsole(ATTACH_PARENT_PROCESS).

For the rest, I can't really help you. I never programmed in .NET. That's why the code pasted above is in C/C++.

Good luck…

By: Jonathan Counihan

Jonathan Counihan — Tue, 03 Nov 2009 07:24:33 +0000

Thanks Crayon for your post. I have modified what you have posted to fit my situation but unfortunately I can't seem to get GetConsoleTitle to work! The error code I get is 183, "Cannot create a file when that file already exists." and I have no idea why! The string builder comes back empty.

I have followed this post http://www.informit.com/guides/content.aspx?g=dotnet&seqNum=109 to use the GetConsoleTitle, but I can't seem to get it to work.

My code for the main function is currently this:

StringBuilder sb = new StringBuilder(1000000);
UInt32 buffSize = (UInt32)sb.Capacity;
UInt32 titleLen = GetConsoleTitle(sb, buffSize);

if (titleLen > 0 &&
(sb.ToString().Substring(sb.Length – 7, 7) == "cmd.exe"))
{
//LaunchedByCmdexe = true;
}

if (args.Length == 1 && args[0] == "-help")
{
InitConsoleHandles();

Console.WriteLine("MyApp help is this");

ReleaseConsoleHandles();
}
else
{
Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}

Any ideas? Thanks.

By: Crayon

Crayon — Mon, 02 Nov 2009 22:36:13 +0000

You might want to add some protection:

char Title[MAX_PATH] = "";
if(GetConsoleTitle(Title, MAX_PATH) && strlen(Title) >= 7 && strcmp(&Title[strlen(Title) - 7], "cmd.exe") != 0)
{
// Launched by cmd.exe
}