Read and write Open XML files (MS Office 2007)

// Excel2007ReadWrite created by Zeljko Svedic. This source code is free to use, modify and 
// incorporate in your software products. This code is not owned by GemBoxSoftware.com or is
// related in any way to GemBox.Spreadsheet Free/Professional .NET component.

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

namespace Excel2007ReadWrite
{
    public partial class ExcelRWForm : Form
    {
        private const string tempDir = @"..\..\TEMP";
        private const string templateFile = @"..\..\Template.xlsx";

        private DataTable data = new DataTable();

        public ExcelRWForm()
        {
            InitializeComponent();

            this.textBoxInput.Text = @"..\..\Input\In.xlsx";
            this.textBoxOutput.Text = @"..\..\Output\Out.xlsx";

            this.data.Columns.Add("ID", Type.GetType("System.Int32"));
            this.data.Columns.Add("FirstName", Type.GetType("System.String"));
            this.data.Columns.Add("LastName", Type.GetType("System.String"));

            this.dataGridView1.DataSource = data;
        }

        private void buttonSelectInput_Click(object sender, EventArgs e)
        {
            this.openFileDialog1.FileName = this.textBoxInput.Text;

            if (this.openFileDialog1.ShowDialog(this) == DialogResult.OK)
                this.textBoxInput.Text = this.openFileDialog1.FileName;
        }

        private void buttonSelectOutput_Click(object sender, EventArgs e)
        {
            this.saveFileDialog1.FileName = this.textBoxOutput.Text;

            if (this.saveFileDialog1.ShowDialog(this) == DialogResult.OK)
                this.textBoxOutput.Text = this.saveFileDialog1.FileName;
        }

        private void buttonReadInput_Click(object sender, EventArgs e)
        {
            // Get the input file name from the text box.
            string fileName = this.textBoxInput.Text;

            // Delete contents of the temporary directory.
            ExcelRW.DeleteDirectoryContents(ExcelRWForm.tempDir);

            // Unzip input XLSX file to the temporary directory.
            ExcelRW.UnzipFile(fileName, ExcelRWForm.tempDir);

            // Open XML file with table of all unique strings used in the workbook..
            FileStream fs = new FileStream(ExcelRWForm.tempDir + @"\xl\sharedStrings.xml",
                FileMode.Open, FileAccess.Read);
            // ..and call helper method that parses that XML and returns an array of strings.
            ArrayList stringTable = ExcelRW.ReadStringTable(fs);

            // Open XML file with worksheet data..
            fs = new FileStream(ExcelRWForm.tempDir + @"\xl\worksheets\sheet1.xml",
                FileMode.Open, FileAccess.Read);
            // ..and call helper method that parses that XML and fills DataTable with values.
            ExcelRW.ReadWorksheet(fs, stringTable, this.data);
        }

        private void buttonWriteOutput_Click(object sender, EventArgs e)
        {
            // Get the output file name from the text box.
            string fileName = this.textBoxOutput.Text;

            // Delete contents of the temporary directory.
            ExcelRW.DeleteDirectoryContents(ExcelRWForm.tempDir);

            // Unzip template XLSX file to the temporary directory.
            ExcelRW.UnzipFile(ExcelRWForm.templateFile, ExcelRWForm.tempDir);

            // We will need two string tables; a lookup Hashtable for fast searching and 
            // an ordinary ArrayList where items are sorted by their index.
            Hashtable lookupTable;

            // Call helper methods which creates both tables from input data.
            ArrayList stringTable = ExcelRW.CreateStringTables(this.data, out lookupTable);

            // Create XML file..
            FileStream fs = new FileStream(ExcelRWForm.tempDir + @"\xl\sharedStrings.xml",
                FileMode.Create);
            // ..and fill it with unique strings used in the workbook
            ExcelRW.WriteStringTable(fs, stringTable);

            // Create XML file..
            fs = new FileStream(ExcelRWForm.tempDir + @"\xl\worksheets\sheet1.xml",
                FileMode.Create);
            // ..and fill it with rows and columns of the DataTable.
            ExcelRW.WriteWorksheet(fs, this.data, lookupTable);

            // ZIP temporary directory to the XLSX file.
            ExcelRW.ZipDirectory(ExcelRWForm.tempDir, fileName);

            // If checkbox is checked, show XLSX file in Excel 2007.
            if (this.checkBoxOpenFile.Checked)
                System.Diagnostics.Process.Start(fileName);
        }
    }
}