Question

We need to place a check box (and caption for it) in the header of a NavBarGroup. Is there a way to do this?

Answer 1

We created a NavBarGroupChecked class (NavBarGroupChecked.cs) that inherits from NavBarGroup and can just be dropped in to replace it. It adds a RepositoryItemCheckEdit member that tracks the checkbox and implements custom draw. It has a Checked property that tells you if it is checked and an event that will be called when the Checked status changes. That’s pretty much it. Just drops in and works.

Code is below and also downloadable here.

// built from http://www.devexpress.com/example=E2061

using System;
using System.ComponentModel;
using System.Drawing;
using System.Reflection;
using System.Windows.Forms;
using DevExpress.XtraEditors.Drawing;
using DevExpress.XtraEditors.Repository;
using DevExpress.XtraEditors.ViewInfo;
using DevExpress.XtraNavBar;
using DevExpress.XtraNavBar.ViewInfo;

namespace AutoTagCore.net.windward.controls
{
    /// <summary>
    /// A NavBarGroup that has a check box (with caption) in its header.
    /// </summary>
    public class NavBarGroupChecked : NavBarGroup
    {

        /// <summary>
        /// Occurs when the Checked property value has been changed. 
        /// </summary>
        public event EventHandler CheckedChanged;

        private const int CHECK_BOX_WIDTH = 15;
        private bool isLocked;
        private RepositoryItemCheckEdit _GroupEdit;
        private NavBarControl _NavBarControl;
        private Rectangle hotRectangle;

        /// <summary>
        /// Initializes a new instance of the <see cref="T:DevExpress.XtraNavBar.NavBarGroup"/> class, with the specified caption.
        /// </summary>
        /// <param name="caption">A string representing the NavBar group's caption.</param>
        public NavBarGroupChecked(string caption)
            : base(caption)
        {
            ctor();
        }

        private void ctor()
        {
            GroupEdit = new RepositoryItemCheckEdit { GlyphAlignment = DevExpress.Utils.HorzAlignment.Far };
            GroupEdit.Appearance.Options.UseTextOptions = true;
            GroupEdit.Appearance.TextOptions.HAlignment = DevExpress.Utils.HorzAlignment.Far;
            GroupEdit.GlyphAlignment = DevExpress.Utils.HorzAlignment.Far;
            ItemChanged += NavBarGroupChecked_ItemChanged;
        }

        private void NavBarGroupChecked_ItemChanged(object sender, System.EventArgs e)
        {
            if (NavBar != NavBarControl)
                NavBarControl = NavBar;
        } 


        /// <summary>
        /// Creates an instance of the <see cref="T:DevExpress.XtraNavBar.NavBarGroup"/> class.
        /// </summary>
        public NavBarGroupChecked()
        {
            ctor();
        }

        /// <summary>
        /// The NavBarControl that owns this. This must be set to work.
        /// </summary>
        private NavBarControl NavBarControl
        {
            get { return _NavBarControl; }
            set { UnsubscribeEvents(value); _NavBarControl = value; SubscribeEvents(value); }
        }

        private void SubscribeEvents(NavBarControl navBarControl)
        {
            if (navBarControl == null)
                return;
            NavBarControl.CustomDrawGroupCaption += NavBarControl_CustomDrawGroupCaption;
            NavBarControl.MouseClick += NavBarControl_MouseClick;
        }

        private void UnsubscribeEvents(NavBarControl navBarControl)
        {
            if (navBarControl != null)
                return;
            NavBarControl.CustomDrawGroupCaption -= NavBarControl_CustomDrawGroupCaption;
            NavBarControl.MouseClick -= NavBarControl_MouseClick;
        }

        /// <summary>
        /// true if the box is checked.
        /// </summary>
        public bool Checked { get; set; }

        /// <summary>
        /// The indent of the check box for the end of the header.
        /// </summary>
        public int CheckIndent { get; set; }

        ///<summary>
        /// The check box displayed in the header.
        ///</summary>
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
        public RepositoryItemCheckEdit GroupEdit
        {
            get { return _GroupEdit; }
            set { _GroupEdit = value; }
        }

        private Rectangle GetCheckBoxBounds(Rectangle fixedCaptionBounds)
        {
            return new Rectangle(fixedCaptionBounds.Right - CHECK_BOX_WIDTH - CheckIndent, fixedCaptionBounds.Top, CHECK_BOX_WIDTH, fixedCaptionBounds.Height); 
        }

        private bool IsCustomDrawNeeded(NavBarGroup group)
        {
            return GroupEdit != null && NavBarControl != null && !isLocked && group == this;
        }

        private void NavBarControl_CustomDrawGroupCaption(object sender, CustomDrawNavBarElementEventArgs e)
        {
            NavGroupInfoArgs infoArgs = (NavGroupInfoArgs) e.ObjectInfo;
            if (!IsCustomDrawNeeded(infoArgs.Group))
                return;
            try
            {
                isLocked = true;
                BaseNavGroupPainter painter = NavBarControl.View.CreateGroupPainter(NavBarControl);
                Rectangle checkBoxBounds = GetCheckBoxBounds(infoArgs.CaptionBounds);
                painter.DrawObject(infoArgs);
                DrawCheckBox(e.Graphics, checkBoxBounds);
                e.Handled = true;
            }
            finally
            {
                isLocked = false;
            }
        }

        private void DrawCheckBox(Graphics g, Rectangle r)
        {
            BaseEditPainter painter = GroupEdit.CreatePainter();
            BaseEditViewInfo info = GroupEdit.CreateViewInfo();
            info.EditValue = Checked;
            SizeF textBounds = info.Appearance.CalcTextSize(g, GroupEdit.Caption, 500);
            int totalWidth = (int)textBounds.Width + r.Width + 10;
            info.Bounds = new Rectangle(r.Right - totalWidth, r.Y, totalWidth, r.Height);
            info.CalcViewInfo(g);
            ControlGraphicsInfoArgs args = new ControlGraphicsInfoArgs(info, new DevExpress.Utils.Drawing.GraphicsCache(g), r);
            painter.Draw(args);
            args.Cache.Dispose();
        }

        private static NavBarViewInfo GetNavBarView(NavBarControl NavBar)
        {
            PropertyInfo pi = typeof(NavBarControl).GetProperty("ViewInfo", BindingFlags.Instance | BindingFlags.NonPublic);
            return pi.GetValue(NavBar, null) as NavBarViewInfo;
        }

        private bool IsCheckBox(Point p)
        {
            NavBarHitInfo hi = NavBarControl.CalcHitInfo(p);
            if (hi.Group == null || hi.Group != this)
                return false;
            NavBarViewInfo vi = GetNavBarView(NavBarControl);
            vi.Calc(NavBarControl.ClientRectangle);
            NavGroupInfoArgs groupInfo = vi.GetGroupInfo(hi.Group);
            Rectangle checkBounds = GetCheckBoxBounds(groupInfo.CaptionBounds);
            hotRectangle = checkBounds;
            return checkBounds.Contains(p);
        }

        private void NavBarControl_MouseClick(object sender, MouseEventArgs e)
        {
            if (!IsCheckBox(e.Location))
                return;
            Checked = !Checked;
            NavBarControl.Invalidate(hotRectangle);
            if (CheckedChanged != null)
                CheckedChanged(sender, e);
        }
    }
}