Displaying large amount of data in DataGridView

DataGridView supports the special mode (Virtual Mode). The basic idea is that inside the control not stored any data.
In given below example of the primitive electronic table, the data stored in the hashtable.The electronic table has a large amount of cells. In this example the number of cells equals to 100000 lines * 100 columns = 10000000. Also the programm save and loads changed cells on the disk

Note: The SerializableDictionary can be found here

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); 
            } 
        } 
    } 
}


 
 
 

2 Responses to “Displaying large amount of data in DataGridView”

  1. Salah
    14. May 2009 at 11:15

    That’s a nice implementation, I have almost the same functionality for my application, and I use a datagridview but the more thing I have it is that when I open file from the OpenFileDialog the Choosen file Opens more seven related files and it display it in a datagridview which is in a TabControl and everything is good till now, but the thing I stuck with it that the datagrid view display the same data for the seven files in whole the tabs which was read it from the last file, do you have any Idea how to solve this…

  2. tarasn
    16. May 2009 at 08:56

    Send me you sources .It seems to be a bug .

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