using System; 

using System.Collections.Generic; 

using System.ComponentModel; 

using System.Data; 

using System.Drawing; 

using System.IO; 

using System.Text; 

using System.Windows.Forms; 

using System.Xml.Serialization; 

namespace Devintelligence.Example { 

    public partial class Form1 : Form 

    { 

        #region Fields  

        public SerializableDictionary<string, int> data = new SerializableDictionary<string, int>(); 

        private Font systemFont; 

        private XmlSerializer serializer = new XmlSerializer(typeof(SerializableDictionary<string, int>)); 

        #endregion  

        public Form1() 

        { 

            InitializeComponent(); 

        } 

        private void Form1_Load(object sender, EventArgs e) 

        { 

            if (File.Exists(FilePath)) 

            { 

                // load from file & desirialize  

                using (FileStream filestream = File.OpenRead(FilePath)) 

                { 

                    data = serializer.Deserialize(filestream) as SerializableDictionary<string, int>; 

                } 

            } 

            ((ISupportInitialize)dataGridView1).BeginInit(); 

            dataGridView1.VirtualMode = true; 

            dataGridView1.CellValueNeeded += new DataGridViewCellValueEventHandler(dataGridView1_CellValueNeeded); 

            dataGridView1.CellValuePushed += new DataGridViewCellValueEventHandler(dataGridView1_CellValuePushed); 

            // create columns  

            for (int i = 0; i < 100 ; i++) 

            { 

                string name = string.Format("{0}", i); 

                dataGridView1.Columns.Add(name, name); 

            } 

            dataGridView1.RowCount = 100000; 

            systemFont = new Font(dataGridView1.Font,FontStyle.Bold); 

            ((ISupportInitialize)dataGridView1).EndInit(); 

        } 

        /// <summary>  

        /// Calculates the unique hash key based on row and column indexes. 

        /// </summary>  

        /// <param name="rowIndex">Index of the row.</param>  

        /// <param name="columnIndex">Index of the column.</param>  

        /// <returns></returns>  

        private static string CalculateKey(int rowIndex, int columnIndex) 

        { 

            return string.Format("{0}_{1}", rowIndex, columnIndex); 

        } 

        /// <summary>  

        /// Handles the CellValuePushed event of the dataGridView1 control. 

        /// </summary>  

        /// <param name="sender">The source of the event.</param>  

        /// <param name="e">The <see cref="T:System.Windows.Forms.DataGridViewCellValueEventArgs"/> 

        /// instance containing the event data.</param>  

        void dataGridView1_CellValuePushed(object sender, DataGridViewCellValueEventArgs e) 

        { 

            data[CalculateKey(e.RowIndex, e.ColumnIndex)] = Convert.ToInt32(e.Value); 

            // mark changed cells  

            dataGridView1[e.ColumnIndex, e.RowIndex].Style.BackColor = Color.LightPink; 

            dataGridView1[e.ColumnIndex, e.RowIndex].Style.Font = systemFont; 

        } 

        /// <summary>  

        /// Handles the CellValueNeeded event of the dataGridView1 control. 

        /// </summary>  

        /// <param name="sender">The source of the event.</param>  

        /// <param name="e">The <see cref="T:System.Windows.Forms.DataGridViewCellValueEventArgs"/>  

        /// instance containing the event data.</param>  

        void dataGridView1_CellValueNeeded(object sender, DataGridViewCellValueEventArgs e) 

        { 

            int value; 

            if (data.TryGetValue(CalculateKey(e.RowIndex, e.ColumnIndex), out value)) 

            { 

                e.Value = value; 

                // mark changed cells  

                dataGridView1[e.ColumnIndex, e.RowIndex].Style.BackColor = Color.LightPink; 

                dataGridView1[e.ColumnIndex, e.RowIndex].Style.Font = systemFont; 

            } 

            else  

            { 

                e.Value = e.ColumnIndex*e.RowIndex; 

            } 

        } 

        private static string FilePath 

        { 

            get  

            { 

                // the data file will be saved in file named data.xml  

                return Path.Combine(Application.StartupPath, "data.xml"); 

            } 

        } 

        private void Form1_FormClosing(object sender, FormClosingEventArgs e) 

        { 

            // serialize & save entered data  

            using (FileStream filestream = File.Open(FilePath, FileMode.Create)) 

            { 

                serializer.Serialize(filestream, data); 

            } 

        } 

    } 

}