C#

private void Form1_Load(object sender, EventArgs e)
{
    string fileName = "oote.oost";
    int numint = 0;

    if (File.Exists(fileName))
    {
        BinaryReader binReader = new BinaryReader(File.Open(fileName, FileMode.Open));
        try
        {
            numint = binReader.ReadInt32();
        }
        // If the end of the stream is reached before reading
        // the four data values, ignore the error and use the
        // default settings for the remaining values.
        catch (EndOfStreamException ex)
        {
            // This is just for your info, should not get here
            MessageBox.Show("Unable to read [numint]", "File Read Error");
        }
        finally
        {
            binReader.Close();
        }
    }

    if (numint >= 5)
    {
        MessageBox.Show("Sorry too many runs", "Limit Exceeded");
        Application.Exit();
    }
    else
    {
        BinaryWriter binWriter = new BinaryWriter(File.Open(fileName, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None));
        try
        {
            binWriter.Write(numint + 1);
        }
        catch
        {
        }
        finally
        {
            // Just to be sure
            binWriter.Flush();
            binWriter.Close();
        }
    }
}

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

        string fileName = "oote.oost";
        int numint = 0;

        if (File.Exists(fileName))
        {
            BinaryReader binReader = new BinaryReader(File.Open(fileName, FileMode.Open));
            try
            {
                numint = binReader.ReadInt32();
            }
            // If the end of the stream is reached before reading
            // the four data values, ignore the error and use the
            // default settings for the remaining values.
            catch (EndOfStreamException ex)
            {
                // This is just for your info, should not get here
                MessageBox.Show("Unable to read [numint]", "File Read Error");
            }
            finally
            {
                binReader.Close();
            }
        }

        if (numint < 5)
        {
            BinaryWriter binWriter = new BinaryWriter(File.Open(fileName, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None));
            try
            {
                binWriter.Write(numint + 1);
            }
            catch
            {
            }
            finally
            {
                // Just to be sure
                binWriter.Flush();
                binWriter.Close();
            }

            // Everything is OK so run the app
            Application.Run(new Form1());
        }
        else
        {
            // numint exceeded designated high value, skip Application.Run, let user know
            // and bomb out.
            MessageBox.Show("Sorry too many runs", "Limit Exceeded");
        }
    }
}

Ben Magee wrote:

By hardware dongle do you mean memory stick?

Luc Pattyn

Have a look at my entry for the lean-and-mean competition; please provide comments, feedback, discussion, and don’t forget to vote for it! Thank you.

Luc Pattyn wrote:

you are well aware is not the way to implement trial limitations. real solutions would use access to a web server, or a hardware dongle

private void JoinFiles(string[] files, string outputFileName)
{
    byte[] buffer = new byte[0x1000];

    using (FileStream fsSave = new FileStream(outputFileName, FileMode.CreateNew, FileAccess.Write, FileShare.None))
    {
        foreach (string file in files)
        {
            using (FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Read, FileShare.Read))
            {
                while (true)
                {
                    int count = fs.Read(buffer, 0, buffer.Length);
                    if (count <= 0) break;

                    fsSave.Write(buffer, 0, count);
                }
            }
        }
    }
}

[Category("Appearance")]
public Color CountryTextBoxBackColor
{
    get
    {
        return this.countryTextBox.BackColor;
    }

    set
    {
        this.countryTextBox.BackColor = value;
    }
}