C#

public partial class MainWindow : Window
   {


       Verdieping etage;

       public MainWindow()
       {
           InitializeComponent();

           Verdieping etage = (Verdieping)0;
           lblHuidigeVerdieping.Content = etage.ToString();
       }

           enum Verdieping: sbyte
       {
           kelder =-1,
           gelijksvloers,
           een,
           twee,
           drie

       }
       void WijzigVerdiepingUp()
       {
           etage++;
           lblHuidigeVerdieping.Content = etage.ToString();

       }
       void WijzigVerdiepDown()
       {
           etage--;
           lblHuidigeVerdieping.Content = etage.ToString();
       }


       private void btnUp_Click(object sender, RoutedEventArgs e)
       {

           WijzigVerdiepingUp();
        }

       private void btnDown_Click(object sender, RoutedEventArgs e)
       {
           WijzigVerdiepDown();
       }
   }

<pre lang="c#">using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Linq;
using Outlook = Microsoft.Office.Interop.Outlook;
using Office = Microsoft.Office.Core;
using System.Drawing;
using System.Diagnostics;
using System.Text.RegularExpressions;
using System.Windows.Forms;
using System.Text.RegularExpressions;


namespace FirstOutlookAddIn
{
    public partial class ThisAddIn
    {
        public static string[] data = new string[10];
        public static Stopwatch timer = new Stopwatch();
        Outlook.NameSpace outlookNameSpace;
        Outlook.MAPIFolder inbox;
        Outlook.Items items;

        private void ThisAddIn_Startup(object sender, System.EventArgs e)
        {

            timer = Stopwatch.StartNew(); ReadMail();
            outlookNameSpace = this.Application.GetNamespace("MAPI");
            inbox = outlookNameSpace.GetDefaultFolder(
                    Microsoft.Office.Interop.Outlook.
                    OlDefaultFolders.olFolderInbox);
            items = inbox.Items;

            items.ItemAdd += new Outlook.ItemsEvents_ItemAddEventHandler(ReadSingleMail); // Modified method to run for single email

        }

        private void ThisAddIn_Shutdown(object sender, System.EventArgs e)
        {
            // Hinweis: Outlook löst dieses Ereignis nicht mehr aus. Wenn Code vorhanden ist, der 
            // ausgeführt werden muss, wenn Outlook geschlossen wird, informieren Sie sich unter http://go.microsoft.com/fwlink/?LinkId=506785
        }

        static void ReadSingleMail(dynamic item)
        {
            string bodyText; // Email body
            string mydocpath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments); //Path to My Documents

            if (item != null)
            {
                bodyText = item.Body;
            }
            else
            {
                return; // If no e-mail body, exit function.
            }
        }

        static void ReadMail()
        {
            //Set up OCR
            string bodyText;
            string mydocpath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);

            //Get unread emails from Inbox
            Microsoft.Office.Interop.Outlook.Application app = null;
            Microsoft.Office.Interop.Outlook._NameSpace ns = null;
            Microsoft.Office.Interop.Outlook.MAPIFolder inboxFolder = null;
            app = new Microsoft.Office.Interop.Outlook.Application();
            ns = app.GetNamespace("MAPI");
            inboxFolder = ns.GetDefaultFolder(Microsoft.Office.Interop.Outlook.OlDefaultFolders.olFolderInbox);
            Outlook.Items unreadItems = inboxFolder.Items.Restrict("[Unread]=true");
            int max_runs;
            //Go through each Unread email
            if (unreadItems.Count > 10) { max_runs = 10; }
            else max_runs = unreadItems.Count;

            for (int counter = 1; counter <= max_runs; counter++)
            {
                //Reinitialize Data array
                for (int index = 0; index <= 8; index++)
                {
                    data[index] = "";
                }
                dynamic item = unreadItems[counter];
                bodyText = item.Body;
                Match match = Regex.Match(bodyText, "Insert searched pattern here");

                if (match.Success)
                {
                    MessageBox.Show(match.Value);
                    match = match.NextMatch();
                }

            }            
        }

        #region Von VSTO generierter Code

        /// <summary>
        /// Erforderliche Methode für die Designerunterstützung.
        /// Der Inhalt der Methode darf nicht mit dem Code-Editor geändert werden.
        /// </summary>
        private void InternalStartup()
        {
            this.Startup += new System.EventHandler(ThisAddIn_Startup);
            this.Shutdown += new System.EventHandler(ThisAddIn_Shutdown);
        }

        #endregion
    }
}

Hi,

how can i set windows form over other programs at the desktop in c#?
i mean i have a form that is like a tool bar that always

has to be at top on the screen and all other programs that are running(like chrome, ie..) should be below it.

the form must by always visible to the user (topmost=true), and will not hide part of other programs windows.