Head First C# Code: Chapter 10
Excuse Manager
Form1.cs

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

namespace _0_Excuse_Manager
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void UpdateForm(bool Changed)
        {
            if (!Changed)
            {
                this.description.Text = currentExcuse.Description;
                this.results.Text = currentExcuse.Results;
                this.lastUsed.Value = currentExcuse.LastUsed;
                if (!String.IsNullOrEmpty(currentExcuse.ExcusePath))
                    FileDate.Text = File.GetLastWriteTime(currentExcuse.ExcusePath).ToString();
                this.Text = "Excuse Manager";
            }
            else
                this.Text = "Excuse Manager*";
            this.formChanged = Changed;
        }


        private Excuse currentExcuse = new Excuse();
        private string selectedFolder = "";
        private string formChanged = false;
        Random random = new Random();

        private void folder_Click(object sender, EventArgs e)
        {
            folderBrowserDialog1.SelectedPath = selectedFolder;
            DialogResult result = folderBrowserDialog1.ShowDialog();
            if (result == DialogResult.OK)
            {
                selectedFolder = folderBrowserDialog1.SelectedPath;
                save.Enabled = true;
                open.Enabled = true;
                randomExcuse.Enabled = true;
            }
        }

        private void save_Click(object sender, EventArgs e)
        {
            if (String.IsNullOrEmpty(description.Text) || String.IsNullOrEmpty(results.Text))
            {
                MessageBox.Show("Please specify an excuse and a result",
                     "Unable to save", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                return;
            }
            saveFileDialog1.InitialDirectory = selectedFolder;
            saveFileDialog1.Filter = "Text files (*.txt)|*.txt|All files (*.*)|*.*";
            saveFileDialog1.FileName = description.Text + ".txt";
            DialogResult result = saveFileDialog1.ShowDialog();
            if (result == DialogResult.OK)
            {
                selectedFolder = folderBrowserDialog1.SelectedPath;
                save.Enabled = true;
                open.Enabled = true;
                randomExcuse.Enabled = true;
            }
        }

        private void save_Click(object sender, EventArgs e)
        {
            if (String.IsNullOrEmpty(description.Text) || String.IsNullOrEmpty(results.Text))
            {
                MessageBox.Show("Please specify an excuse and a result",
                     "Unable to save", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                return;
            }
            saveFileDialog1.InitialDirectory = selectedFolder;
            saveFileDialog1.Filter = "Excuse files (*.excuse)|*.excuse|All files (*.*)|*.*";
            saveFileDialog1.FileName = description.Text + ".excuse";
            DialogResult result = saveFileDialog1.ShowDialog();
            if (result == DialogResult.OK)
            {
                currentExcuse.Save(saveFileDialog1.FileName);
                UpdateForm(false);
                MessageBox.Show("Excuse written");
            }
        }

        private void open_Click(object sender, EventArgs e)
        {
            if (CheckChanged())
            {
                openFileDialog1.InitialDirectory = selectedFolder;
                openFileDialog1.Filter =
                  "Excuse files (*.excuse)|*.excuse|All files (*.*)|*.*";
                openFileDialog1.FileName = description.Text + ".excuse";
                DialogResult result = openFileDialog1.ShowDialog();
                if (result == DialogResult.OK)
                {
                    bool clearForm = false;
                    try
                    {
                        currentExcuse = new Excuse(openFileDialog1.FileName);
                        try
                        {
                            UpdateForm(false);
                        }
                        catch
                        {
                            MessageBox.Show("The excuse file ‘"
                                + openFileDialog1.FileName + "’ is invalid",
                                "Unable to open the excuse");
                            clearForm = true;
                        }
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show("An error occurred while opening the excuse ‘"
                            + openFileDialog1.FileName + "’\n" + ex.Message,
                            "Unable to open the excuse", MessageBoxButtons.OK,
                            MessageBoxIcon.Error);
                        clearForm = true;
                    }
                    finally
                    {
                        if (clearForm)
                        {
                            description.Text = "";
                            results.Text = "";
                            lastUsed.Value = DateTime.Now;
                        }
                    }

                }
            }
        }
            

        private void randomExcuse_Click(object sender, EventArgs e)
        {
            if (CheckChanged())
            {
                currentExcuse = new Excuse(random, selectedFolder);
                UpdateForm(false);
            }
        }

        private bool CheckChanged()
        {
            if (formChanged)
            {
                DialogResult result = MessageBox.Show(
                      "The current excuse has not been saved. Continue?",
                       "Warning", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);
                if (result == DialogResult.No)
                    return false;
            }
            return true;
        }

        private void description_TextChanged(object sender, EventArgs e)
        {
            currentExcuse.Description = description.Text;
            UpdateForm(true);
        }

        private void results_TextChanged(object sender, EventArgs e)
        {
            currentExcuse.Results = results.Text;
            UpdateForm(true);
        }

        private void lastUsed_ValueChanged(object sender, EventArgs e)
        {
            currentExcuse.LastUsed = lastUsed.Value;
            UpdateForm(true);
        }


    }
}