Simple C# application eating memory

Question

Alright so basicly I have this simple application running in system tray that has one timer. Every tick it performs a check to see if a given directory and file exists, and based on the result it changes its icon.

The problem is every single timer tick the memory for the application raises ~100kb. I currently have it running for about 5 mins and it already uses 40MB of memory, which is unacceptable for such "micro" application.

Here's my code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.IO;
using System.Reflection;
using System.Windows.Forms;

namespace Tray
{
    public partial class Main : Form
    {
        string drive = "C:\\";
        string file  = "test.txt";

        System.Drawing.Image imgRed     = Image.FromFile("res\\icon-red.png");
        System.Drawing.Image imgOrange  = Image.FromFile("res\\icon-orange.png");
        System.Drawing.Image imgGreen   = Image.FromFile("res\\icon-green.png");
        System.Drawing.Icon  icoRed      = System.Drawing.Icon.ExtractAssociatedIcon("res\\icon-red.ico");
        System.Drawing.Icon  icoOrange   = System.Drawing.Icon.ExtractAssociatedIcon("res\\icon-orange.ico");
        System.Drawing.Icon  icoGreen    = System.Drawing.Icon.ExtractAssociatedIcon("res\\icon-green.ico");

        public Main()
        {
            InitializeComponent();
        }

        public static string ShowPrompt(string text, string caption)
        {
            Form prompt = new Form();
            prompt.Width = 500;
            prompt.Height = 150;
            prompt.Text = caption;
            Label textLabel = new Label() { Left = 50, Top = 20, Text = text };
            TextBox textBox = new TextBox() { Left = 50, Top = 50, Width = 400 };
            Button confirmation = new Button() { Text = "Ok", Left = 350, Width = 100, Top = 70 };
            confirmation.Click += (sender, e) => { prompt.Close(); };
            prompt.Controls.Add(confirmation);
            prompt.Controls.Add(textLabel);
            prompt.Controls.Add(textBox);
            prompt.ShowDialog();
            return textBox.Text;
        }

        public void updateInfo(){
            this.statusDrive.Text = "Drive [" + drive + "]";
            this.statusFile.Text = "File [" + drive + file + "]";
        }

        public void exec(){
            int status = 0;

            this.trayIcon.Text = "[Drive - ";
            if (Directory.Exists(drive)){
                this.statusDrive.Text += " - OK";
                this.statusDrive.Image = imgGreen;
                status++;
                this.trayIcon.Text += "OK] ";
            } else{
                this.statusDrive.Text += " - FAIL";
                this.statusDrive.Image = imgRed;
                this.trayIcon.Text += "FAIL] ";
            }

            this.trayIcon.Text += "[File - ";
            if (File.Exists(drive + file))
            {
                this.statusFile.Text += " - OK";
                this.statusFile.Image = imgGreen;
                status++;
                this.trayIcon.Text += "OK] ";
            }
            else
            {
                this.statusFile.Text += " - FAIL";
                this.statusFile.Image = imgRed;
                this.trayIcon.Text += "FAIL] ";
            }

            switch (status)
            {
                case 2:
                    this.Icon = icoGreen;
                    this.trayIcon.Icon = icoGreen;
                    this.status.Image = imgGreen;
                    break;
                case 1:
                    this.Icon = icoOrange;
                    this.trayIcon.Icon = icoOrange;
                    this.status.Image = imgOrange;
                    break;
                case 0:
                default:
                    this.Icon = icoRed;
                    this.trayIcon.Icon = icoRed;
                    this.status.Image = imgRed;
                    break;
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            this.Hide();

        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            updateInfo();
            exec();
        }

        private void chDrive_Click(object sender, EventArgs e)
        {
            this.drive = ShowPrompt("Enter drive path", "Change drive");
        }

        private void chFile_Click(object sender, EventArgs e)
        {
            this.file = ShowPrompt("Enter new file path:", "Change file");
        }

        private void exitToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }
    }
}

I already tried to optimize the app by preloading the icons and images into variables and assigning those to the appropriate properties, however this didn't solve my problem.

Also, note that I managed to hide my main window by doing this (in Program.cs):

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;

namespace Tray
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Main mForm = new Main();
            Application.Run();
        }
    }
}

UPDATE

I just noticed that the memory usage climbs up to 50MB and drops to 20MB afterwards (and goes up again). Is this something I can possibly address or is it a windows "issue"?

Answer 1

I'm going to take a stab at it being the string concatenations happening once a second. Consider using a StringBuilder. 40MB is nothing though really.

RE: Your update. The Garbage Collector is reclaiming the memory as it sees fit.