Minimize all open windows

[pethil]

Hello,

I'm trying to minimize all open windows.

I have tried to get a few api's to find all open windows and close them, but i cant manage to do it...

first i thought i had a working app, i was getting a list of processes and close their open windows. altho that didnt work wid a few windows, like explorer (windows 7).

anyway i can use EnumWindow to loop throw all windows and minimize them?

a little example would be very helpful.

Thanks in advance,
Peter

[HanneSThEGreaT]

Include this ontop of your class :

using System.Runtime.InteropServices; //For APIs

Add the following 2 APIs, with their Constants :

        [DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
        static extern IntPtr FindWindow(string lpClassName, string lpWindowName); //Find A Window
        [DllImport("user32.dll", EntryPoint = "SendMessage", SetLastError = true)]
        static extern IntPtr SendMessage(IntPtr hWnd, Int32 Msg, IntPtr wParam, IntPtr lParam); //Send System Message

        const int WM_COMMAND = 0x111;
        const int MIN_ALL = 419;
        const int MIN_ALL_UNDO = 416;

Add this in your Button's click event :

            IntPtr lHwnd = FindWindow("Shell_TrayWnd", null); //Get  Access To TaskBar Window
            SendMessage(lHwnd, WM_COMMAND, (IntPtr)MIN_ALL, IntPtr.Zero); //Minimize All
            System.Threading.Thread.Sleep(2000); //Let It Do Its Stuff
            SendMessage(lHwnd, WM_COMMAND, (IntPtr)MIN_ALL_UNDO, IntPtr.Zero);

Voila!

I hope it helps!

[Arjay]

Hannes, you may want to use SendMessageTimeout instead.

If you don't, SendMessage will cause your app to hang if any target app (window) is not responding.

[zips]

I'm trying to minimize all open windows.

If you are talking about all the window forms being part of the same app, you can make one of the forms (usually your main form) the Owner of the others. It is a property of each form. Then if you minimize any one of them, all will minimize together, and they will all Restore together.

//  somewhere in your main form:

Form SomeForm = new Form();
SomeForm.Owner = this;

[HanneSThEGreaT]

Originally Posted by Arjay

Hannes, you may want to use SendMessageTimeout instead.

Good call!

I'll see how I can modify this

[MadHatter]

couldn't you also use postmessage and the broadcast handle to accomplish the same thing.

[HanneSThEGreaT]

OK, here's the Modified code, now using SendMessageTimeOut :

        [DllImport("user32.dll", EntryPoint = "FindWindow", SetLastError = true)]
        static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
       // [DllImport("user32.dll", EntryPoint = "SendMessage", SetLastError = true)]
       // static extern IntPtr SendMessage(IntPtr hWnd, Int32 Msg, IntPtr wParam, IntPtr lParam);
        [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        static extern IntPtr SendMessageTimeout(
            IntPtr windowHandle,
            uint Msg,
            IntPtr wParam,
            IntPtr lParam,
            SendMessageTimeoutFlags flags,
            uint timeout,
            out IntPtr result);

        [Flags]
        enum SendMessageTimeoutFlags : uint
        {
            SMTO_NORMAL = 0x0,
            SMTO_BLOCK = 0x1,
            SMTO_ABORTIFHUNG = 0x2,
            SMTO_NOTIMEOUTIFNOTHUNG = 0x8
        }

        const int WM_COMMAND = 0x111;
        const int MIN_ALL = 419;
        const int MIN_ALL_UNDO = 416;

        private void button1_Click(object sender, EventArgs e)
        {
            IntPtr OutResult;
            IntPtr lHwnd = FindWindow("Shell_TrayWnd", null);
            SendMessageTimeout(lHwnd, WM_COMMAND, (IntPtr)MIN_ALL, IntPtr.Zero, SendMessageTimeoutFlags.SMTO_ABORTIFHUNG, 2000, out OutResult);
            System.Threading.Thread.Sleep(2000);
            SendMessageTimeout(lHwnd, WM_COMMAND, (IntPtr)MIN_ALL_UNDO, IntPtr.Zero, SendMessageTimeoutFlags.SMTO_ABORTIFHUNG, 2000, out OutResult);
        }
    }

Originally Posted by MadHatter

couldn't you also use postmessage and the broadcast handle to accomplish the same thing.

Yes

[HanneSThEGreaT]

Easiest way yet, without using APIs, is to make use of the Shell32 class directly

Set a reference to Microsoft Shell Controls And Automation, to do this follow these steps :
Click Project
Click Add Reference
Click the COM tab
Scroll down and select Microsoft Shell Controls And Automation
Click OK

Add a Button and give it the Text : Show Desktop
Switch to code View, add the following using statement :

using Shell32;

Just above your Button's code ( or where ever ), add the following variable :

private static Shell32.Shell shellInterface = new Shell32.Shell();

In your Button's Click event, type the following :

        private void button1_Click(object sender, EventArgs e)
        {
            shellInterface.MinimizeAll(); 

        }

Your whole project should look like this :

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using Shell32;


namespace ShowDesktop
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private static Shell32.Shell shellInterface = new Shell32.Shell(); 
        private void button1_Click(object sender, EventArgs e)
        {
            shellInterface.MinimizeAll(); 

        }
    }
}

I am attaching the sample here as well

I hope this also helps!

[pethil]

Thank you all for your help!

I managed to create my little app that can minimize all windows on just one screen in my 4 screen setup.

mapped to Ctrl + 1, 2, 3 and 4. makes it a quite usefull app.

attaching source if someone wants to take a look at it.
Definitely badly written but it does what it's suppose to.

Thanks again!

[HanneSThEGreaT]

Thanx for sharing!

Everyone starts with writing "badly written programs"
With experience, it imporves, keep on keeping on !