CheckMarkSelection.cs

// Multiple row selection using custom checkbox column (web style)

using System;
using System.Drawing;
using System.Collections;
using System.Windows.Forms;
using DevExpress.XtraGrid;
using DevExpress.XtraGrid.Columns;
using DevExpress.XtraEditors.Controls;
using DevExpress.XtraEditors.Repository;
using DevExpress.XtraGrid.Views.Base;
using DevExpress.XtraGrid.Views.Grid;
using DevExpress.XtraGrid.Views.Grid.ViewInfo;
using DevExpress.Utils.Drawing;
using DevExpress.XtraEditors.ViewInfo;
using DevExpress.XtraEditors.Drawing;

namespace DevExpress.XtraGrid.Selection {

    public class GridCheckMarksSelection {
        protected GridView _view;
        protected ArrayList selection;
        GridColumn column;
        RepositoryItemCheckEdit edit;
        const int CheckboxIndent = 4;

        public GridCheckMarksSelection() {
            selection = new ArrayList();
        }

        public GridCheckMarksSelection(GridView view) : this() {
            View = view;
        }
        public GridView View {
            get { return _view; }
            set {
                if(_view != value) {
                    Detach();
                    Attach(value);
                }
            }
        }
        public GridColumn CheckMarkColumn { get { return column; } }

        public int SelectedCount { get { return selection.Count; } }
        public object GetSelectedRow(int index) {
            return selection[index];
        }
        public int GetSelectedIndex(object row) {
            return selection.IndexOf(row);
        }
        public void ClearSelection() {
            selection.Clear();
            Invalidate();
        }
        public void SelectAll() {
            selection.Clear();
            // fast (won't work if the grid is filtered)
            //if(_view.DataSource is ICollection)
            //	selection.AddRange(((ICollection)_view.DataSource));
            //else
            // slow:
            for(int i = 0; i < _view.DataRowCount; i++)
                selection.Add(_view.GetRow(i));
            Invalidate();
        }
        public void SelectGroup(int rowHandle, bool select) {
            if(IsGroupRowSelected(rowHandle) && select) return;
            for(int i = 0; i < _view.GetChildRowCount(rowHandle); i++) {
                int childRowHandle = _view.GetChildRowHandle(rowHandle, i);
                if(_view.IsGroupRow(childRowHandle))
                    SelectGroup(childRowHandle, select);
                else
                    SelectRow(childRowHandle, select, false);
            }
            Invalidate();
        }
        public void SelectRow(int rowHandle, bool select) {
            SelectRow(rowHandle, select, true);
        }
        public void InvertRowSelection(int rowHandle) {
            if(View.IsDataRow(rowHandle)) {
                SelectRow(rowHandle, !IsRowSelected(rowHandle));
            }
            if(View.IsGroupRow(rowHandle)) {
                SelectGroup(rowHandle, !IsGroupRowSelected(rowHandle));
            }
        }
        public bool IsGroupRowSelected(int rowHandle) {
            for(int i = 0; i < _view.GetChildRowCount(rowHandle); i++) {
                int row = _view.GetChildRowHandle(rowHandle, i);
                if(_view.IsGroupRow(row)) {
                    if(!IsGroupRowSelected(row)) return false;
                }
                else
                    if(!IsRowSelected(row)) return false;
            }
            return true;
        }
        public bool IsRowSelected(int rowHandle) {
            if(_view.IsGroupRow(rowHandle))
                return IsGroupRowSelected(rowHandle);

            object row = _view.GetRow(rowHandle);
            return GetSelectedIndex(row) != -1;
        }

        protected virtual void Attach(GridView view) {
            if(view == null) return;
            selection.Clear();
            this._view = view;
            view.BeginUpdate();
            try {
                edit = view.GridControl.RepositoryItems.Add("CheckEdit") as RepositoryItemCheckEdit;

                column = view.Columns.Add();
                column.OptionsColumn.AllowSort = DevExpress.Utils.DefaultBoolean.False;
                column.Visible = true;
                column.VisibleIndex = 0;
                column.FieldName = "CheckMarkSelection";
                column.Caption = "Mark";
                column.OptionsColumn.ShowCaption = false;
                column.OptionsColumn.AllowEdit = false;
                column.OptionsColumn.AllowSize = false;
                column.UnboundType = DevExpress.Data.UnboundColumnType.Boolean;
                column.Width = GetCheckBoxWidth();
                column.ColumnEdit = edit;

                view.Click += new EventHandler(View_Click);
                view.CustomDrawColumnHeader += new ColumnHeaderCustomDrawEventHandler(View_CustomDrawColumnHeader);
                view.CustomDrawGroupRow += new RowObjectCustomDrawEventHandler(View_CustomDrawGroupRow);
                view.CustomUnboundColumnData += new CustomColumnDataEventHandler(view_CustomUnboundColumnData);
                view.KeyDown += new KeyEventHandler(view_KeyDown);
                view.RowStyle += new RowStyleEventHandler(view_RowStyle);
            }
            finally {
                view.EndUpdate();
            }
        }
        protected virtual void Detach() {
            if(_view == null) return;
            if(column != null)
                column.Dispose();
            if(edit != null) {
                _view.GridControl.RepositoryItems.Remove(edit);
                edit.Dispose();
            }

            _view.Click -= new EventHandler(View_Click);
            _view.CustomDrawColumnHeader -= new ColumnHeaderCustomDrawEventHandler(View_CustomDrawColumnHeader);
            _view.CustomDrawGroupRow -= new RowObjectCustomDrawEventHandler(View_CustomDrawGroupRow);
            _view.CustomUnboundColumnData -= new CustomColumnDataEventHandler(view_CustomUnboundColumnData);
            _view.KeyDown -= new KeyEventHandler(view_KeyDown);
            _view.RowStyle -= new RowStyleEventHandler(view_RowStyle);

            _view = null;
        }
        protected int GetCheckBoxWidth() {
            CheckEditViewInfo info = edit.CreateViewInfo() as CheckEditViewInfo;
            int width = 0;
            GraphicsInfo.Default.AddGraphics(null);
            try {
                width = info.CalcBestFit(GraphicsInfo.Default.Graphics).Width;
            }
            finally {
                GraphicsInfo.Default.ReleaseGraphics();
            }
            return width + CheckboxIndent * 2;
        }
        protected void DrawCheckBox(GraphicsCache cache, Rectangle r, bool Checked) {
            CheckEditViewInfo info;
            CheckEditPainter painter;
            ControlGraphicsInfoArgs args;
            info = edit.CreateViewInfo() as CheckEditViewInfo;
            painter = edit.CreatePainter() as CheckEditPainter;
            info.EditValue = Checked;
            info.Bounds = r;
            info.CalcViewInfo(null);
            args = new ControlGraphicsInfoArgs(info, cache, r);
            painter.Draw(args);
        }
        void Invalidate() {
            _view.CloseEditor();
            _view.BeginUpdate();
            _view.EndUpdate();
        }
        void SelectRow(int rowHandle, bool select, bool invalidate) {
            if(IsRowSelected(rowHandle) == select) return;
            object row = _view.GetRow(rowHandle);
            if(select)
                selection.Add(row);
            else
                selection.Remove(row);
            if(invalidate) {
                Invalidate();
            }
        }
        void view_CustomUnboundColumnData(object sender, CustomColumnDataEventArgs e) {
            if(e.Column == CheckMarkColumn) {
                if(e.IsGetData)
                    e.Value = IsRowSelected(View.GetRowHandle(e.ListSourceRowIndex));
                else
                    SelectRow(View.GetRowHandle(e.ListSourceRowIndex), (bool)e.Value);
            }
        }
        void view_KeyDown(object sender, KeyEventArgs e) {
            if(View.FocusedColumn != column || e.KeyCode != Keys.Space) return;
            InvertRowSelection(View.FocusedRowHandle);
        }
        void View_Click(object sender, EventArgs e) {
            GridHitInfo info;
            Point pt = _view.GridControl.PointToClient(Control.MousePosition);
            info = _view.CalcHitInfo(pt);
            if(info.Column == column) {
                if(info.InColumn) {
                    if(SelectedCount == _view.DataRowCount)
                        ClearSelection();
                    else
                        SelectAll();
                }
                if(info.InRowCell) {
                    InvertRowSelection(info.RowHandle);
                }
            }
            if(info.InRow && _view.IsGroupRow(info.RowHandle) && info.HitTest != GridHitTest.RowGroupButton) {
                InvertRowSelection(info.RowHandle);
            }
        }
        void View_CustomDrawColumnHeader(object sender, ColumnHeaderCustomDrawEventArgs e) {
            if(e.Column == column) {
                e.Info.InnerElements.Clear();
                e.Painter.DrawObject(e.Info);
                DrawCheckBox(e.Cache, e.Bounds, SelectedCount == _view.DataRowCount);
                e.Handled = true;
            }
        }
        void View_CustomDrawGroupRow(object sender, RowObjectCustomDrawEventArgs e) {
            GridGroupRowInfo info = e.Info as GridGroupRowInfo;
            info.GroupText = "         " + info.GroupText.TrimStart();
            e.Appearance.FillRectangle(e.Cache, e.Bounds);
            e.Painter.DrawObject(e.Info);

            Rectangle r = info.ButtonBounds;
            r.Offset(r.Width + CheckboxIndent * 2 - 1, 0);
            DrawCheckBox(e.Cache, r, IsGroupRowSelected(e.RowHandle));
            e.Handled = true;
        }
        void view_RowStyle(object sender, RowStyleEventArgs e) {
            if(IsRowSelected(e.RowHandle)) {
                e.Appearance.BackColor = SystemColors.Highlight;
                e.Appearance.ForeColor = SystemColors.HighlightText;
            }
        }
    }
}