DevExpress DateEditor Popout YearMonth View

YearMonthEditor.cs

using DevExpress.XtraEditors;
using DevExpress.XtraEditors.Calendar;
using DevExpress.XtraEditors.Controls;
using DevExpress.XtraEditors.Popup;
using DevExpress.XtraEditors.Repository;

DateTime MinDateTime = new DateTime(1900, 1, 1);
/// <summary>
/// DateEditor that display year-month and only can select year-month view 
/// </summary>
public class DateEditYearMonth : DateEdit
{
    public int StoredDate { get; set; }

    public DateEditYearMonth(DateEdit de, int storedDate)
        : base()
    {
        (de.Parent as Control).Controls.Add(this);
        Location = de.Location;
        Size = de.Size;
        
        //This can avoid dropdown error when in Windows XP
        Properties.VistaDisplayMode = DevExpress.Utils.DefaultBoolean.True;
        
        Properties.AppearanceFocused.BackColor = de.Properties.AppearanceFocused.BackColor;
        Properties.Mask.EditMask = "y";
        Properties.DisplayFormat.FormatString = "y";
        Properties.DisplayFormat.FormatType = DevExpress.Utils.FormatType.DateTime;
        Properties.EditFormat.FormatString = "y";
        Properties.EditFormat.FormatType = DevExpress.Utils.FormatType.DateTime;
        Properties.NullDate = de.Properties.NullDate = MinDateTime;

        if (de.DateTime == MinDateTime) EditValue = null;
        else DateTime = de.DateTime;

        StoredDate = storedDate;

        KeyDown += (s, e) =>
        {
            if (e.KeyCode == Keys.Delete) //use `DELETE` to clear
            {
                if (Properties.ReadOnly)
                    e.Handled = false;
                else
                {
                    CancelPopup();
                    EditValue = MinDateTime;
                    e.Handled = true;
                }
            }
        };
    }

    protected override PopupBaseForm CreatePopupForm()
    {
        return new YearMonthVistaPopupDateEditForm(this, StoredDate);
    }

    protected override void CreateRepositoryItem()
    {
        fProperties = new YearMonthRepositoryItemDateEdit(this);
    }

    private class YearMonthRepositoryItemDateEdit : RepositoryItemDateEdit
    {
        public YearMonthRepositoryItemDateEdit(DateEdit dateEdit)
        {
            SetOwnerEdit(dateEdit);
        }

        public override bool ShowToday
        {
            get
            {
                return false;
            }
        }
    }

    private class YearMonthVistaPopupDateEditForm : VistaPopupDateEditForm
    {
        private int _storedDate
        {
            get;
            set;
        }

        public YearMonthVistaPopupDateEditForm(DateEdit ownerEdit, int storedDate)
            : base(ownerEdit)
        {
            this._storedDate = storedDate;
        }

        protected override DateEditCalendar CreateCalendar()
        {
            return new YearMonthVistaDateEditCalendar(OwnerEdit.Properties,
                OwnerEdit.EditValue, _storedDate);
        }
    }

    private class YearMonthVistaDateEditCalendar : VistaDateEditCalendar
    {
        private int _storedDate
        {
            get;
            set;
        }

        public YearMonthVistaDateEditCalendar(RepositoryItemDateEdit item,
            object editDate, int storedDate)
            : base(item, editDate)
        {
            _storedDate = storedDate;
        }

        protected override void Init()
        {
            base.Init();
            View = DateEditCalendarViewType.YearInfo;
        }

        protected override void OnItemClick(CalendarHitInfo hitInfo)
        {
            DayNumberCellInfo cell = (DayNumberCellInfo)hitInfo.HitObject;
            if (View == DateEditCalendarViewType.YearInfo)
            {
                DateTime date;
                if (_storedDate > 0)
                    date = new DateTime(DateTime.Year, cell.Date.Month, _storedDate);
                else
                {
                    date = DateTimeFuncs.LastDayOfMonth(new DateTime(DateTime.Year, cell.Date.Month, 1));
                }
                OnDateTimeCommit(date, false);
            }
            else
            {
                base.OnItemClick(hitInfo);
            }
        }
    }
}

YearMonthFunctions.cs

using DevExpress.XtraEditors;
using DevExpress.XtraEditors.Controls;
using DevExpress.XtraEditors.Repository;
using DevExpress.XtraGrid.Columns;

DateTime MinDateTime = new DateTime(1900, 1, 1);
/// <summary>
/// Set assigned DateEditor only display year-month and on can select year-month view. Moreover, you can assigned stored date
/// </summary>
/// <param name="de">assigned DateEditor</param>
/// <param name="date">default is 1. If -1, that means the last date of month</param>
public static void SetYearMonth(this DateEdit de, int date = 1)
{
    DateEditYearMonth deym = new DateEditYearMonth(de, date);
    de.Visible = false;
    de.EnabledChanged += (s, e) => { deym.Enabled = de.Enabled; };
    de.PropertiesChanged += (s, e) =>
    {
        deym.Properties.ReadOnly = de.Properties.ReadOnly;
        deym.DateTime = de.DateTime;
    };

    de.EditValueChanged += (s, e) =>
    {
        if (deym.Properties.ReadOnly) deym.DateTime = de.DateTime;
        else
        {
            if (de.IsEmpty()) deym.DateTime = MinDateTime;
            
            //Avoid scroll or type date to cause error
            if (deym.EditValue == de.EditValue) return;

            DateTime lastDate = MyDateTimeFuncs.LastDayOfMonth(deym.DateTime);
            if (date == -1)
            {
                de.EditValue = lastDate;
                return;
            }

            DateTime firstDate = MyDateTimeFuncs.FirstDayOfMonth(deym.DateTime);

            DateTime queryDate = firstDate.AddDays(date - 1);
            if (queryDate > lastDate) de.EditValue = lastDate;
            else de.EditValue = queryDate;
        }
    };

    deym.EditValueChanged += (s, e) =>
    {
        if (deym.Properties.ReadOnly || deym.IsEmpty()) return;
        de.DateTime = deym.DateTime;
    };
}

/// <summary>
/// Set girdcolumn only display year-month
/// </summary>
/// <param name="colTime">assigned Girdcolumn</param>
public static void DisplayYearMonthFormat(GridColumn colTime)
{
    RepositoryItemDateEdit ride = new RepositoryItemDateEdit();
    ride.Mask.Culture = My.CultureName;
    ride.Mask.EditMask = My.DateMask;
    ride.NullDate = MinDateTime;
    ride.MinValue = MinDateTime;
    colTime.DisplayFormat.FormatType = DevExpress.Utils.FormatType.DateTime;
    colTime.DisplayFormat.FormatString = "y";
    ride.Mask.UseMaskAsDisplayFormat = false;
    colTime.ColumnEdit = ride;
}