Make my WinForms application behave just like a Console application when using Console.WriteLine()


I have a .NET WinForms application written in C#. The application has two operational modes:

  • Regular GUI mode.
  • Possibility to execute calls with a CLI.

When I run my application from a Cmd window, the output appears on screen, but the application does not close until I press the Enter key.

I read on another stackoverflow posting that the easiest way of writing to the Console is by changing the application type to "Console Application". When doing so, the output of the app is written to the Console exactly how I want it to be:

  1. I type in the command
  2. The output appears below my command.
  3. And the application exits normally.

However, doing so will also open a Console window when starting the application without any command line arguments. I am able to hide the Console window, but the program startup takes a little bit of time so the Console window is always visible for a short period of time - this is a No-Go.

I then tried with sticking to the application type "Windows Application". I have created a very simple example:

    static class Program
        static void Main(string[] args)
            if (args.Length > 0)

                Console.WriteLine("First Line");
                Console.WriteLine("Second Line");
                Console.WriteLine("Third Line");
                Console.WriteLine("Fourth Line");
                Console.WriteLine("Fifth Line");
                Console.WriteLine("Sixth Line");
                Console.WriteLine("Seventh Line");

                Application.Run(new Form1());

        public static void CreateConsole()

            // Instead, get the defaultStdOut using PInvoke
            SafeFileHandle defaultStdOut = NativeMethods.CreateFile("CONOUT$", EFileAccess.GenericRead | EFileAccess.GenericWrite, EFileShare.Write, IntPtr.Zero, ECreationDisposition.OpenExisting, 0, IntPtr.Zero);
            NativeMethods.SetStdHandle(NativeMethods.STD_OUTPUT_HANDLE, defaultStdOut.DangerousGetHandle());    // also seems dangerous... there may be an alternate signature for SetStdHandle that takes SafeFileHandle.

            TextWriter writer = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = true };


    internal static class NativeMethods
        [DllImport("kernel32.dll", SetLastError = true)]
        public static extern bool FreeConsole();

        [DllImport("kernel32", SetLastError = true)]
        public static extern bool AttachConsole(int dwProcessId);

        internal const int STD_OUTPUT_HANDLE = -11;

        // method signature changed per
        internal static extern bool SetStdHandle(int nStdHandle, IntPtr hHandle);

        [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        internal static extern SafeFileHandle CreateFile(string lpFileName, EFileAccess dwDesiredAccess, EFileShare dwShareMode, IntPtr lpSecurityAttributes, ECreationDisposition dwCreationDisposition, EFileAttributes dwFlagsAndAttributes, IntPtr hTemplateFile);

    public enum EFileAccess : uint
        // Standart Section

        AccessSystemSecurity = 0x1000000,   // AccessSystemAcl access type
        MaximumAllowed = 0x2000000,     // MaximumAllowed access type

        Delete = 0x10000,
        ReadControl = 0x20000,
        WriteDAC = 0x40000,
        WriteOwner = 0x80000,
        Synchronize = 0x100000,

        StandardRightsRequired = 0xF0000,
        StandardRightsRead = ReadControl,
        StandardRightsWrite = ReadControl,
        StandardRightsExecute = ReadControl,
        StandardRightsAll = 0x1F0000,
        SpecificRightsAll = 0xFFFF,

        FILE_READ_DATA = 0x0001,        // file & pipe
        FILE_LIST_DIRECTORY = 0x0001,       // directory
        FILE_WRITE_DATA = 0x0002,       // file & pipe
        FILE_ADD_FILE = 0x0002,         // directory
        FILE_APPEND_DATA = 0x0004,      // file
        FILE_ADD_SUBDIRECTORY = 0x0004,     // directory
        FILE_CREATE_PIPE_INSTANCE = 0x0004, // named pipe
        FILE_READ_EA = 0x0008,          // file & directory
        FILE_WRITE_EA = 0x0010,         // file & directory
        FILE_EXECUTE = 0x0020,          // file
        FILE_TRAVERSE = 0x0020,         // directory
        FILE_DELETE_CHILD = 0x0040,     // directory
        FILE_READ_ATTRIBUTES = 0x0080,      // all
        FILE_WRITE_ATTRIBUTES = 0x0100,     // all

        // Generic Section

        GenericRead = 0x80000000,
        GenericWrite = 0x40000000,
        GenericExecute = 0x20000000,
        GenericAll = 0x10000000,

        StandardRightsRequired |
        Synchronize |

        StandardRightsRead |
        FILE_READ_DATA |
        FILE_READ_EA |

        StandardRightsWrite |
        FILE_WRITE_EA |

        FILE_GENERIC_EXECUTE = StandardRightsExecute | FILE_READ_ATTRIBUTES | FILE_EXECUTE | Synchronize }

    public enum EFileShare : uint
        /// <summary>
        /// </summary>
        None = 0x00000000,
        /// <summary>
        /// Enables subsequent open operations on an object to request read access. 
        /// Otherwise, other processes cannot open the object if they request read access. 
        /// If this flag is not specified, but the object has been opened for read access, the function fails.
        /// </summary>
        Read = 0x00000001,
        /// <summary>
        /// Enables subsequent open operations on an object to request write access. 
        /// Otherwise, other processes cannot open the object if they request write access. 
        /// If this flag is not specified, but the object has been opened for write access, the function fails.
        /// </summary>
        Write = 0x00000002,
        /// <summary>
        /// Enables subsequent open operations on an object to request delete access. 
        /// Otherwise, other processes cannot open the object if they request delete access.
        /// If this flag is not specified, but the object has been opened for delete access, the function fails.
        /// </summary>
        Delete = 0x00000004

    public enum ECreationDisposition : uint
        /// <summary>
        /// Creates a new file. The function fails if a specified file exists.
        /// </summary>
        New = 1,
        /// <summary>
        /// Creates a new file, always. 
        /// If a file exists, the function overwrites the file, clears the existing attributes, combines the specified file attributes, 
        /// and flags with FILE_ATTRIBUTE_ARCHIVE, but does not set the security descriptor that the SECURITY_ATTRIBUTES structure specifies.
        /// </summary>
        CreateAlways = 2,
        /// <summary>
        /// Opens a file. The function fails if the file does not exist. 
        /// </summary>
        OpenExisting = 3,
        /// <summary>
        /// Opens a file, always. 
        /// If a file does not exist, the function creates a file as if dwCreationDisposition is CREATE_NEW.
        /// </summary>
        OpenAlways = 4,
        /// <summary>
        /// Opens a file and truncates it so that its size is 0 (zero) bytes. The function fails if the file does not exist.
        /// The calling process must open the file with the GENERIC_WRITE access right. 
        /// </summary>
        TruncateExisting = 5

    public enum EFileAttributes : uint
        Readonly = 0x00000001,
        Hidden = 0x00000002,
        System = 0x00000004,
        Directory = 0x00000010,
        Archive = 0x00000020,
        Device = 0x00000040,
        Normal = 0x00000080,
        Temporary = 0x00000100,
        SparseFile = 0x00000200,
        ReparsePoint = 0x00000400,
        Compressed = 0x00000800,
        Offline = 0x00001000,
        NotContentIndexed = 0x00002000,
        Encrypted = 0x00004000,
        Write_Through = 0x80000000,
        Overlapped = 0x40000000,
        NoBuffering = 0x20000000,
        RandomAccess = 0x10000000,
        SequentialScan = 0x08000000,
        DeleteOnClose = 0x04000000,
        BackupSemantics = 0x02000000,
        PosixSemantics = 0x01000000,
        OpenReparsePoint = 0x00200000,
        OpenNoRecall = 0x00100000,
        FirstPipeInstance = 0x00080000

When I run the program without command line arguments, everything works fine. However, when I run the program with command line arguments from a Cmd window, I see the following output:

Command Line Arguments

As you can see, there is a new line and another "prompt line" appears (I don't know what this line is called). Also, the program does not exit until I press a key. Using the > for redirecting the output into a file also does not work.

How can I achieve the behavior of a Console application (i.e. is it possible to "simply" start the app hidden instead of hiding it afterwards?). In macOS there is the possibility to run an application as an agent so it starts hidden. Is there somethign similiar in C# / Windows?

P.S: I have tried every other solution that was posted here on stackoverflow and the outcome was pretty much always the same.

asked on Stack Overflow Sep 17, 2019 by inexcitus

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