using System;using System.Windows.Forms;public class CalendarColumn : DataGridViewColumn{    public CalendarColumn() : base(new CalendarCell())    {    }    public override DataGridViewCell CellTemplate    {        get        {            return base.CellTemplate;        }        set        {            // Ensure that the cell used for the template is a CalendarCell.            if (value != null &&                 !value.GetType().IsAssignableFrom(typeof(CalendarCell)))            {                throw new InvalidCastException("Must be a CalendarCell");            }            base.CellTemplate = value;        }    }}public class CalendarCell : DataGridViewTextBoxCell{    public CalendarCell()        : base()    {        // Use the short date format.        this.Style.Format = "d";    }    public override void InitializeEditingControl(int rowIndex, object         initialFormattedValue, DataGridViewCellStyle dataGridViewCellStyle)    {        // Set the value of the editing control to the current cell value.        base.InitializeEditingControl(rowIndex, initialFormattedValue,             dataGridViewCellStyle);        CalendarEditingControl ctl =             DataGridView.EditingControl as CalendarEditingControl;        ctl.Value = (DateTime)this.Value;    }    public override Type EditType    {        get        {            // Return the type of the editing contol that CalendarCell uses.            return typeof(CalendarEditingControl);        }    }    public override Type ValueType    {        get        {            // Return the type of the value that CalendarCell contains.            return typeof(DateTime);        }    }    public override object DefaultNewRowValue    {        get        {            // Use the current date and time as the default value.            return DateTime.Now;        }    }}class CalendarEditingControl : DateTimePicker, IDataGridViewEditingControl{    DataGridView dataGridView;    private bool valueChanged = false;    int rowIndex;    public CalendarEditingControl()    {        this.Format = DateTimePickerFormat.Short;    }    // Implements the IDataGridViewEditingControl.EditingControlFormattedValue     // property.    public object EditingControlFormattedValue    {        get        {            return this.Value.ToShortDateString();        }        set        {            String newValue = value as String;            if (newValue != null)            {                this.Value =http://www.mamicode.com/ DateTime.Parse(newValue);            }        }    }    // Implements the     // IDataGridViewEditingControl.GetEditingControlFormattedValue method.    public object GetEditingControlFormattedValue(        DataGridViewDataErrorContexts context)    {        return EditingControlFormattedValue;    }    // Implements the     // IDataGridViewEditingControl.ApplyCellStyleToEditingControl method.    public void ApplyCellStyleToEditingControl(        DataGridViewCellStyle dataGridViewCellStyle)    {        this.Font = dataGridViewCellStyle.Font;        this.CalendarForeColor = dataGridViewCellStyle.ForeColor;        this.CalendarMonthBackground = dataGridViewCellStyle.BackColor;    }    // Implements the IDataGridViewEditingControl.EditingControlRowIndex     // property.    public int EditingControlRowIndex    {        get        {            return rowIndex;        }        set        {            rowIndex = value;        }    }    // Implements the IDataGridViewEditingControl.EditingControlWantsInputKey     // method.    public bool EditingControlWantsInputKey(        Keys key, bool dataGridViewWantsInputKey)    {        // Let the DateTimePicker handle the keys listed.        switch (key & Keys.KeyCode)        {            case Keys.Left:            case Keys.Up:            case Keys.Down:            case Keys.Right:            case Keys.Home:            case Keys.End:            case Keys.PageDown:            case Keys.PageUp:                return true;            default:                return false;        }    }    // Implements the IDataGridViewEditingControl.PrepareEditingControlForEdit     // method.    public void PrepareEditingControlForEdit(bool selectAll)    {        // No preparation needs to be done.    }    // Implements the IDataGridViewEditingControl    // .RepositionEditingControlOnValueChange property.    public bool RepositionEditingControlOnValueChange    {        get        {            return false;        }    }    // Implements the IDataGridViewEditingControl    // .EditingControlDataGridView property.    public DataGridView EditingControlDataGridView    {        get        {            return dataGridView;        }        set        {            dataGridView = value;        }    }    // Implements the IDataGridViewEditingControl    // .EditingControlValueChanged property.    public bool EditingControlValueChanged    {        get        {            return valueChanged;        }        set        {            valueChanged = value;        }    }    // Implements the IDataGridViewEditingControl    // .EditingPanelCursor property.    public Cursor EditingPanelCursor    {        get        {            return base.Cursor;        }    }    protected override void OnValueChanged(EventArgs eventargs)    {        // Notify the DataGridView that the contents of the cell        // have changed.        valueChanged = true;        this.EditingControlDataGridView.NotifyCurrentCellDirty(true);        base.OnValueChanged(eventargs);    }}public class Form1 : Form{    private DataGridView dataGridView1 = new DataGridView();    [STAThreadAttribute()]    public static void Main()    {        Application.Run(new Form1());    }    public Form1()    {        this.dataGridView1.Dock = DockStyle.Fill;        this.Controls.Add(this.dataGridView1);        this.Load += new EventHandler(Form1_Load);        this.Text = "DataGridView calendar column demo";    }    private void Form1_Load(object sender, EventArgs e)    {        CalendarColumn col = new CalendarColumn();        this.dataGridView1.Columns.Add(col);        this.dataGridView1.RowCount = 5;        foreach (DataGridViewRow row in this.dataGridView1.Rows)        {            row.Cells[0].Value =http://www.mamicode.com/ DateTime.Now;        }    }}