调用C++ dll的方法在C# app打开console window，如何抑制console？

Question

I have written a C++ dll with one published method which simply starts another program with a defined parameter. This method is called from a C# WinForms application.

The published method is triggered from the C# application on a button click. The 2nd application is starting, as intended, but in addition a Windows Console window is opening which outputs nothing.

I want to suppress the console window, but I can't figure out how to do this. When the application I run is terminated, the console window also terminates.

This is what my header and source of the C++ dll looks like:

launcher.h

#pragma once

#ifdef ILJ16_EXPORTS
#define LAUNCHER_EXPORT __declspec(dllexport)
#else
#define LAUNCHER_EXPORT __declspec(dllimport)
#endif // ILJ16_EXPORTS

const char* startParam = "--Q7t0elSDASCrpHQ";

extern "C" LAUNCHER_EXPORT void startProcess();

launcher.cpp

#include "pch.h"
#include "launcher.h"
#include <process.h>
#include <stdio.h>

void startProcess()
{
    char command[256 + 1];
    snprintf(command, sizeof(command), "Test.exe %s", startParam); //Test.exe is the application which has to be started
    int retCode = system(command);
}

In my C# WinForms project I have written the following code

using System;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        [DllImport("ilj16.dll", EntryPoint = "startProcess")]
        public static extern void startProcess();
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            startProcess();
        }
    }
}

Answer 1

From reading the windows documentation it appears that the system(const char*) call opens a cmd.exe prompt and then executes the string.

system documentation

The system function passes command to the command interpreter, which executes the string as an operating-system command. system uses the COMSPEC and PATH environment variables to locate the command-interpreter file CMD.exe. If command is NULL, the function just checks whether the command interpreter exists.

From a quick google it looks like the best way to solve this is to use _popen , CreateProcessA , or you could try to hide/close the cmd.exe using something like this .

Also, if your C++ dll is only opening another program, you could eliminate the need for a dll and do it all in C# with this C# class . In the first example at that link there is a simple solution:

    using (Process myProcess = new Process())
    {
        myProcess.StartInfo.UseShellExecute = false;
        // You can start any process, HelloWorld is a do-nothing example.
        myProcess.StartInfo.FileName = "C:\\HelloWorld.exe";
        myProcess.StartInfo.CreateNoWindow = true;
        myProcess.Start();
        // This code assumes the process you are starting will terminate itself.
        // Given that is is started without a window so you cannot terminate it
        // on the desktop, it must terminate itself or you can do it programmatically
        // from this application using the Kill method.
    }

Answer 2

Instead of startprocess , consider using CreateProcess with STARTUPINFO.wShowWindow set to SW_HIDE .

CreateProcess

Creates a new process and its primary thread. The new process runs in the security context of the calling process