Exception when using console window in a form application

Question

I have a program WFA that also has and command Window. I open the window with AllocConsole(); When I close the console window, I use FreeConsole(); but when I open it again with AllocConsole(); I wanna write and read from it and it throws an exception. The code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Management;
using System.Management.Instrumentation;
using System.Collections.Specialized;
using System.Threading;
using System.Runtime.InteropServices;


    namespace WindowsFormsApplication2
{

class classx
{

    [DllImport("kernel32.dll")]
    public static extern Int32 AllocConsole();
    [DllImport("kernel32.dll")]
    public static extern bool FreeConsole();
    [DllImport("kernel32")]
    public static extern bool AttachConsole();
    [DllImport("kernel32")]
    public static extern bool GetConsoleWindow();
    public static bool z = false;
    [DllImport("kernel32")]
    public static extern bool SetConsoleCtrlHandler(HandlerRoutine HandlerRoutine, bool Add);
    public delegate bool HandlerRoutine(uint dwControlType);
}



public partial class Form1 : Form
{
    NotifyIcon icontask;
    Icon iconone_active;
    Icon iconone_inactive;
    /*Icon icontwo;
    Icon iconthree;
    Icon iconfour;
    Icon iconfive;*/
    Thread Threadworkermy;

    public Form1()
    {
        InitializeComponent();
        this.WindowState = FormWindowState.Minimized;
        this.ShowInTaskbar = false;
        iconone_active = new Icon(".../iconone_active.ico");
        iconone_inactive = new Icon(".../iconone_inactive.ico");
        icontask = new NotifyIcon();
        icontask.Icon = iconone_active;
        icontask.Visible = true;
        Threadworkermy = new Thread(new ThreadStart(checkActivityThread));
        Threadworkermy.Start();

        MenuItem Nameapp = new MenuItem("xr");
        MenuItem quitappitem = new MenuItem("quit program");
        MenuItem OpenGUI = new MenuItem("Open GUI");
        MenuItem Advancedmodewindow = new MenuItem("x");
        ContextMenu contextmenu = new ContextMenu();

        quitappitem.Click += quitappitem_click;
        OpenGUI.Click += OpenGUI_click;
        Advancedmodewindow.Click += Advancedmodewindow_click;
        contextmenu.MenuItems.Add(Nameapp);
        contextmenu.MenuItems[0].Enabled = false;
        contextmenu.MenuItems.Add("-");
        contextmenu.MenuItems.Add(OpenGUI);
        contextmenu.MenuItems.Add(Advancedmodewindow);
        contextmenu.MenuItems.Add("-");
        contextmenu.MenuItems.Add(quitappitem);
        icontask.ContextMenu = contextmenu;

        icontask.Icon = iconone_active;
        icontask.Visible = true;
    }

    private void Advancedmodewindow_click(object sender, EventArgs e)
    {
        classx.AllocConsole();
        Console.WriteLine("X");
        classx.FreeConsole();
    }

    private void OpenGUI_click(object sender, EventArgs e)
    {
        this.ShowInTaskbar = true;
        this.WindowState = FormWindowState.Normal;  
    }

    private void quitappitem_click(object sender, EventArgs e)
    {
        Threadworkermy.Abort();
        icontask.Dispose();
        this.Close();
    }

    public void checkActivityThread()
    {
        try
        {
            while(true)
            {
                Thread.Sleep(100);   
            }
        } catch(ThreadAbortException tbe)
        {

        }

    }

    private void button1_Click(object sender, EventArgs e)
    {
        this.WindowState = FormWindowState.Minimized;
        this.ShowInTaskbar = false;
    }


}
}

Exception that it throws out 'System.IO.IOException' in mscorlib.dll Additional information: The handle is invalid. To those who will be saying to change the type, I can't. (it needs to be WFA application)

Why doesn't

CONSOLE.WRITELINE

and similar code work?

csharpbd · Accepted Answer · 2017-03-05 20:15:55Z

3

The exception is not coming from Open/Close the console. It's coming when you want to write/read something with the console. You have to RESET the standard IO for your console. Every time you have to do this after AllocConsole(). Please check below code, it's tested.

CODE:

private void Advancedmodewindow_click(object sender, EventArgs e)
{
    classx.AllocConsole();

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

    Console.WriteLine("X");

    Console.SetIn(new StreamReader(Console.OpenStandardInput()));
    string line = Console.ReadLine();

    classx.FreeConsole();
}

edited Mar 5, 2017 at 20:15

answered Mar 5, 2017 at 19:43

csharpbd

4,1164 gold badges27 silver badges34 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

dkman Over a year ago

how to do inputs then because when i try to input with Console.ReadLine(); it throws same exception

Armin Over a year ago

If this works for Writes, then for reads you need to duplicate the code and instead of StreamWriter, use StreamReader

dkman Over a year ago

Thx will put it in my code as soon as i get back on pc

csharpbd Over a year ago

And sorry to see that the answer is not accepted yet.

Collectives™ on Stack Overflow

Exception when using console window in a form application

1 Answer 1

4 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related