Initial code, everything seems to be working

MainForm.cs

@@ -0,0 +1,175 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Data;
+using System.Drawing;
+using System.Text;
+using System.Windows.Forms;
+
+namespace FrappeMocha
+{
+    public partial class MainForm : Form
+    {
+        protected Keygen frappeKeygen;
+        private object[] windowsLicenseTypeItems = new object[2];
+        private object[] macLicenseTypeItems = new object[2];
+        private object[] javaLicenseTypeItems = new object[5];
+
+        public MainForm()
+        {
+            InitializeComponent();
+            TypeDropDown.SelectedIndex = 0;
+            productSelect.SelectedIndex = 0;
+            frappeKeygen = new Keygen();
+            this.initDropDownMenuItems();
+        }
+
+        private void initDropDownMenuItems()
+        {
+            TypeDropDown.Items.CopyTo(windowsLicenseTypeItems, 0);
+
+            initJavaLicenseTypeItems();
+            initMacLicenseTypeItems();
+
+            TypeDropDown.Items.Clear();
+            TypeDropDown.Items.AddRange(this.windowsLicenseTypeItems);
+            TypeDropDown.SelectedIndex = 0;
+        }
+
+        private void initJavaLicenseTypeItems()
+        {
+            TypeDropDown.Items.Clear();
+            for (int i = 0; i < 5; i++)
+            {
+                TypeDropDown.Items.Add((char) ('A' + i));
+            }
+            TypeDropDown.Items.CopyTo(this.javaLicenseTypeItems, 0);
+        }
+
+        private void initMacLicenseTypeItems()
+        {
+            TypeDropDown.Items.Clear();
+            for (int i = 0; i < 2; i++)
+            {
+                TypeDropDown.Items.Add((char)('a' + i));
+            }
+            TypeDropDown.Items.CopyTo(this.macLicenseTypeItems, 0);
+        }
+
+        private void submit_Click(object sender, EventArgs e)
+        {
+            switch (productSelect.SelectedIndex)
+            {
+                case 0:
+                    this.keygen(Keygen.LicenseTypes.License3270);
+                    break;
+
+                case 1:
+                    this.keygen(Keygen.LicenseTypes.License5250);
+                    break;
+
+                case 2:
+                    this.keygen(Keygen.LicenseTypes.License3812);
+                    break;
+
+                case 3:
+                    this.keygen(Keygen.LicenseTypes.LicenseTelnet);
+                    break;
+
+                case 4:
+                    this.keygen(Keygen.LicenseTypes.LicenseJava3270);
+                    break;
+
+                case 5:
+                    this.keygen(Keygen.LicenseTypes.LicenseJava5250);
+                    break;
+
+                case 6:
+                    this.keygen(Keygen.LicenseTypes.LicenseJavaTelnet);
+                    break;
+
+                case 7:
+                    this.keygen(Keygen.LicenseTypes.LicenseMac3270);
+                    break;
+
+                case 8:
+                    this.keygen(Keygen.LicenseTypes.LicenseMac5250);
+                    break;
+            }
+        }
+
+        private void TypeDropDown_SelectedIndexChanged(object sender, EventArgs e)
+        {
+            switch (TypeDropDown.SelectedIndex)
+            {
+                case 0:
+                    companyusernamelabel.Text = "Company Name";
+                    break;
+
+                case 1:
+                    companyusernamelabel.Text = "User Name";
+                    break;
+            }
+
+            if (TypeDropDown.Items.Count > 2)
+            {
+                companyusernamelabel.Text = "Name";
+            }
+        }
+
+        private void keygen(Keygen.LicenseTypes license)
+        {
+            if (companytext.Text.Length <= 1)
+            {
+                MessageBox.Show(
+                    (TypeDropDown.SelectedIndex == 0
+                        ? "Company Name"
+                        : "User Name") + " must be longer than one character", "Error",
+                    MessageBoxButtons.OK, MessageBoxIcon.Error);
+                return;
+            }
+
+            string genlicense = frappeKeygen.GenLicense(TypeDropDown.SelectedIndex, companytext.Text, license);
+            if (!frappeKeygen.CheckLicense(genlicense, companytext.Text, license))
+            {
+                MessageBox.Show("Generated license did not pass self check, please try again", "Warning",
+                    MessageBoxButtons.OK,
+                    MessageBoxIcon.Warning);
+
+                return;
+            }
+
+            licensebox.Text = genlicense;
+        }
+
+        private void productSelect_SelectedIndexChanged(object sender, EventArgs e)
+        {
+            switch (productSelect.SelectedIndex)
+            {
+                case 0:
+                case 1:
+                case 2:
+                case 3:
+                    if (this.windowsLicenseTypeItems[0] != null)
+                    {
+                        TypeDropDown.Items.Clear();
+                        TypeDropDown.Items.AddRange(this.windowsLicenseTypeItems);
+                    }
+                    break;
+                case 4:
+                case 5:
+                case 6:
+                    TypeDropDown.Items.Clear();
+                    TypeDropDown.Items.AddRange(this.javaLicenseTypeItems);
+                    break;
+
+                case 7:
+                case 8:
+                    TypeDropDown.Items.Clear();
+                    TypeDropDown.Items.AddRange(this.macLicenseTypeItems);
+                    break;
+            }
+            TypeDropDown.SelectedIndex = 0;
+        }
+    }
+}