Build Your Own DataGrid for Silverlight: Step 2

// Copyright 2008-2009 NETiKA TECH.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System;
using System.Windows;
using Netika.Windows.Controls;
using System.Windows.Controls;

namespace Open.Windows.Controls
{
    /// <summary>
    /// Base control from which the HandyCommand, HandyContainer and HandyNavigator controls are inherited. 
    /// </summary>
    public abstract class HandyListControl: Netika.Windows.Controls.Combo
    {
        public static readonly DependencyProperty HandyScrollerStyleProperty;
        public static readonly DependencyProperty StyleBindingModeProperty;
        public static readonly DependencyProperty HandyItemsPanelModelProperty;
        public static readonly DependencyProperty HandyStatersModelProperty;

        
        static HandyListControl()
        {
            HandyScrollerStyleProperty = DependencyProperty.Register("HandyScrollerStyle", typeof(HandyScrollerStyle), typeof(HandyListControl), new PropertyMetadata(new PropertyChangedCallback(OnHandyScrollerStyleChanged)));
            StyleBindingModeProperty = DependencyProperty.Register("StyleBindingMode", typeof(StyleBindingMode), typeof(HandyListControl), new PropertyMetadata(StyleBindingMode.Late));

            HandyItemsPanelModelProperty = DependencyProperty.Register("HandyItemsPanelModel", typeof(HandyPanelModel), typeof(HandyListControl), new PropertyMetadata(new PropertyChangedCallback(OnHandyItemsPanelModelChanged)));
            HandyStatersModelProperty = DependencyProperty.Register("HandyStatersModel", typeof(HandyStaters), typeof(HandyListControl), new PropertyMetadata(new PropertyChangedCallback(OnHandyStatersModelChanged)));
            
        }

        protected HandyListControl()
        {
            this.LayoutUpdated += new EventHandler(HandyList_LayoutUpdated);
        }

        private void HandyList_LayoutUpdated(object sender, EventArgs e)
        {            
            if (!handyStyleApplied)
            {
                if (StyleBindingMode == StyleBindingMode.Normal)
                    this.ApplyHandyStyle(this.FindHandyStyle());
                else if ((this.ActualHeight > 0) || (this.ActualWidth > 0))
                    this.ApplyHandyStyle(this.FindHandyStyle());
            }
        }

        protected override void InitializeStaters()
        {
            if (this.Style != null)
                base.InitializeStaters();
        }

        protected abstract Style FindHandyStyle();

        /// <summary>
        /// Allows to define when the HandyStyle is applied to a control. 
        /// </summary>
        public StyleBindingMode StyleBindingMode
        {
            get
            {
                return (StyleBindingMode)this.GetValue(StyleBindingModeProperty);
            }
            set
            {
                base.SetValue(StyleBindingModeProperty, value);
            }
        }

        /// <summary>
        /// Allows to select the StatersModel (collection of Stater) that will be used in the HandyContainer control.
        /// </summary>
        public HandyStaters HandyStatersModel
        {
            get
            {
                return (HandyStaters)this.GetValue(HandyStatersModelProperty);
            }
            set
            {
                base.SetValue(HandyStatersModelProperty, value);
            }
        }

        private static void OnHandyStatersModelChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            HandyListControl listControl = (HandyListControl)d;

            listControl.ApplyStatersModel(listControl.GetHandyStatersModel());
        }

        private void ApplyStatersModel(Staters handyStatersModel)
        {
            if (handyStatersModel == null)
                return;

            if (this.StatersModel == null)
                this.StatersModel = handyStatersModel;

        }

        private Staters GetHandyStatersModel()
        {
            if (HandyStatersModel == HandyStaters.None)
                return null;

            return ResourceHelper.FindResource(Enum.GetName(typeof(HandyStaters), HandyStatersModel)) as Staters;

        }

        /// <summary>
        /// Allows to select the PanelModel (not only a Panel but also a value for its properties including the KeyNavigator and the ChildrenAnimator) that will contain the items of the HandyContainer control (ItemsHost)
        /// </summary>
        public HandyPanelModel HandyItemsPanelModel
        {
            get
            {
                return (HandyPanelModel)this.GetValue(HandyItemsPanelModelProperty);
            }
            set
            {
                base.SetValue(HandyItemsPanelModelProperty, value);
            }
        }

        private static void OnHandyItemsPanelModelChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            HandyListControl listControl = (HandyListControl)d;

            listControl.ApplyItemsPanelModel(listControl.GetHandyItemsPanelModel());
        }

        private void ApplyItemsPanelModel(PanelModel handyItemPanelModel)
        {
            if (handyItemPanelModel == null)
                return;

            if (this.ItemsPanelModel == null)
                this.ItemsPanelModel = handyItemPanelModel;

        }

        private PanelModel GetHandyItemsPanelModel()
        {
            if (HandyItemsPanelModel == HandyPanelModel.None)
                return null;

            return ResourceHelper.FindResource(Enum.GetName(typeof(HandyPanelModel), HandyItemsPanelModel)) as PanelModel;
        }
               
        /// <summary>
        /// The HandyScrollerStyle to apply to the Scroller (if any) that is inside the ListControl. 
        /// </summary>
        public HandyScrollerStyle HandyScrollerStyle
        {
            get
            {
                return (HandyScrollerStyle)this.GetValue(HandyScrollerStyleProperty);
            }
            set
            {
                base.SetValue(HandyScrollerStyleProperty, value);
            }
        }

        private static void OnHandyScrollerStyleChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            HandyListControl listControl = (HandyListControl)d;

            listControl.ApplyScrollerStyle(listControl.GetHandyScrollerStyle());
        }

        private void ApplyScrollerStyle(Style handyScrollerStyle)
        {
            if (handyScrollerStyle == null)
                return;
            
            if (this.ScrollerStyle == null)
                this.ScrollerStyle = handyScrollerStyle;
        }

        private Style GetHandyScrollerStyle()
        {
            HandyScrollerStyle handyScrollerStyle = HandyScrollerStyle;

            if (handyScrollerStyle == HandyScrollerStyle.Calculated)
                handyScrollerStyle = GetCalculatedHandyScrollerStyle();

            if (handyScrollerStyle == HandyScrollerStyle.None)
                return null;

            return ResourceHelper.FindResource(Enum.GetName(typeof(HandyScrollerStyle), handyScrollerStyle)) as Style;
        }

        private HandyScrollerStyle GetCalculatedHandyScrollerStyle()
        {
            if (OverflowControl != null)
                return HandyScrollerStyle.NoScrollStyle;

            return HandyScrollerStyle.SmallScrollerStyle;
        }

        /// <summary>
        /// This event occurs when the real style linked to the HandyStyle has been applied to the control. 
        /// </summary>
        public event EventHandler HandyStyleApplied;               
        protected virtual void OnHandyStyleApplied(EventArgs e)
        {
            if (HandyStyleApplied != null)
                HandyStyleApplied(this, e);
        }

        private bool onHandyStyleAppliedEventCalled;
        private bool templateLoaded;
        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            if (handyStyleApplied)
            {
                if (!onHandyStyleAppliedEventCalled)
                {
                    OnHandyStyleApplied(EventArgs.Empty);
                    onHandyStyleAppliedEventCalled = true;
                }
            }

            templateLoaded = true;
           
        }

        private bool handyStyleApplied;
        protected void ApplyHandyStyle(Style style)
        {
            if (style == null)
                return;

            if (this.Style == null)
            {
                this.Style = style;
                handyStyleApplied = true;

                if (templateLoaded && !onHandyStyleAppliedEventCalled)
                    OnHandyStyleApplied(EventArgs.Empty);
            }

        }

        /// <summary>
        /// Gets an item from its index
        /// </summary>
        public HandyListItem GetItemFromIndex(int itemIndex)
        {
            if (this.VirtualMode == VirtualMode.On)
                itemIndex = itemIndex - this.VirtualPageStartIndex;

            if (itemIndex < 0)
                return null;

            UIElementCollection itemsHostChildren = this.ItemsHost.Children;
            if (itemIndex >= itemsHostChildren.Count)
                return null;

            return (HandyListItem)itemsHostChildren[itemIndex];

        }

        /// <summary>
        /// Ensure that an item is located inside the display area of the control
        /// </summary>
        public void EnsureItemVisible(int itemIndex)
        {
            GStackPanel itemsHost = (GStackPanel)this.ItemsHost;
            if (itemIndex < this.VerticalOffset)
            {
                this.VerticalOffset = itemIndex;
            }
            if (itemIndex > this.VerticalOffset + this.ViewportHeight)
            {
                this.VerticalOffset = (int)(itemIndex - this.ViewportHeight);
                if (this.VirtualMode == VirtualMode.On)
                    itemsHost.EnsureVisible(itemIndex - this.VirtualPageStartIndex, EnsureVisibleLocation.Bottom);
                else
                    itemsHost.EnsureVisible(itemIndex, EnsureVisibleLocation.Bottom);
            }
        }
    }
}