Windows Forms: How to Create a License Key in C# Part 2

Add code to handle frmGenerate form

namespace LicenseKey
{
    public partial class frmGenerate : Form
    {
        public frmGenerate()
        {
            InitializeComponent();
        }

        private void btnGenerate_Click(object sender, EventArgs e)
        {
            KeyManager km = new KeyManager(txtProductID.Text);
            KeyValuesClass kv;
            string productKey = string.Empty;
            if (cboLicenseType.SelectedIndex == 0)
            {
                kv = new KeyValuesClass()
                {
                    Type = LicenseType.FULL,
                    Header = Convert.ToByte(9),
                    Footer = Convert.ToByte(6),
                    ProductCode = (byte)ProductCode,//As order of your software
                    Edition = Edition.ENTERPRISE,
                    Version = 1
                };
                if (!km.GenerateKey(kv, ref productKey))//Generate full license key
                    txtProductKey.Text = "ERROR";
            }
            else
            {
                kv = new KeyValuesClass()
                {
                    Type = LicenseType.TRIAL,
                    Header = Convert.ToByte(9),
                    Footer = Convert.ToByte(6),
                    ProductCode = (byte)ProductCode,
                    Edition = Edition.ENTERPRISE,
                    Version = 1,
                    Expiration = DateTime.Now.Date.AddDays(Convert.ToInt32(txtExperience.Text))
                };
                if (!km.GenerateKey(kv, ref productKey))//Generate trial license key
                    txtProductKey.Text = "ERROR";
            }
            txtProductKey.Text = productKey;
        }

        const int ProductCode = 1;

        private void frmGenerate_Load(object sender, EventArgs e)
        {
            cboLicenseType.SelectedIndex = 0;
            //Get computer id, it's unique for each computer
            txtProductID.Text = ComputerInfo.GetComputerId();
        }
    }
}

Add code to handle frmRegistration form

namespace LicenseKey
{
    public partial class frmRegistration : Form
    {
        public frmRegistration()
        {
            InitializeComponent();
        }

        const int ProductCode = 1;

        private void btnOK_Click(object sender, EventArgs e)
        {
            KeyManager km = new KeyManager(txtProductID.Text);
            string productKey = txtProductKey.Text;
            //Check valid
            if(km.ValidKey(ref productKey))
            {
                KeyValuesClass kv = new KeyValuesClass();
                //Decrypt license key
                if (km.DisassembleKey(productKey, ref kv))
                {
                    LicenseInfo lic = new LicenseInfo();
                    lic.ProductKey = productKey;
                    lic.FullName = "FoxLearn";
                    if (kv.Type == LicenseType.TRIAL)
                    {
                        lic.Day = kv.Expiration.Day;
                        lic.Month = kv.Expiration.Month;
                        lic.Year = kv.Expiration.Year;
                    }
                    //Save license key to file
                    km.SaveSuretyFile(string.Format(@"{0}\Key.lic", Application.StartupPath), lic);
                    MessageBox.Show("You have been successfully registered.", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    this.Close();
                }
            }
            else
                MessageBox.Show("Your product key is invalid.", "Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
        }

        private void frmRegistration_Load(object sender, EventArgs e)
        {
            txtProductID.Text = ComputerInfo.GetComputerId();
        }
    }
}

Add code to handle frmAbout form

namespace LicenseKey
{
    public partial class frmAbout : Form
    {
        public frmAbout()
        {
            InitializeComponent();
        }

        private void btnOK_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        const int ProductCode = 1;

        private void frmAbout_Load(object sender, EventArgs e)
        {
            lblProductID.Text = ComputerInfo.GetComputerId();
            KeyManager km = new KeyManager(lblProductID.Text);
            LicenseInfo lic = new LicenseInfo();
            //Get license information from license file
            int value = km.LoadSuretyFile(string.Format(@"{0}\Key.lic", Application.StartupPath), ref lic);
            string productKey = lic.ProductKey;
            //Check valid
            if(km.ValidKey(ref productKey))
            {
                KeyValuesClass kv = new KeyValuesClass();
                //Decrypt license key
                if(km.DisassembleKey(productKey, ref kv))
                {
                    lblProductName.Text = "FoxLearn";
                    lblProductKey.Text = productKey;
                    if (kv.Type == LicenseType.TRIAL)
                        lblLicenseType.Text = string.Format("{0} days", (kv.Expiration - DateTime.Now.Date).Days);
                    else
                        lblLicenseType.Text = "Full";
                }
            }
        }
    }
}

VIDEO TUTORIALS