path: root/Software/Visual_Studio/Tango.SharedUI/Controls/SearchComboBox.cs

using System;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Data;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Threading;

namespace Tango.SharedUI.Controls
{
    [TemplatePart(Name = SearchComboBox.PartEditor, Type = typeof(System.Windows.Controls.TextBox))]
    [TemplatePart(Name = SearchComboBox.PartPopup, Type = typeof(Popup))]
    public class SearchComboBox : ComboBox
    {
        public const string PartEditor = "Search";
        public const string PartPopup = "PART_Popup";
        private int _savedSelectedIndex = -1;
        private bool _editorMouseLeaveFlag = false;

        #region Properties

        private TextBox _editor;

        public TextBox Editor
        {
            get { return _editor; }
            set { _editor = value; }
        }


        private Popup _popup;

        public Popup Popup
        {
            get { return _popup; }
            set { _popup = value; }
        }

        private DispatcherTimer _fetchTimer;

        public DispatcherTimer FetchTimer
        {
            get { return _fetchTimer; }
            set { _fetchTimer = value; }
        }
        

        private string _searchText = "";
        /// <summary>
        /// Gets or sets the search text of TextBox.
        /// </summary>
        public string SearchText
        {
            get { return _searchText; }
            set
            {
                if(_searchText != value && value != null)
                {
                    _searchText = value;
                }
                
            }
        }

        public ListCollectionView SearchItemsList
        {
            get { return (ListCollectionView)GetValue(SearchItemsListProperty); }
            set { SetValue(SearchItemsListProperty, value); }
        }
        /// <summary>
        /// The search items list property for popup items list
        /// </summary>
        public static readonly DependencyProperty SearchItemsListProperty =
            DependencyProperty.Register("SearchItemsList", typeof(ListCollectionView), typeof(SearchComboBox), new PropertyMetadata(default(ObservableCollection<string>)));


        public string SearchParam
        {
            get { return (string)GetValue(SearchParamProperty); }
            set { SetValue(SearchParamProperty, value); }
        }

        public static readonly DependencyProperty SearchParamProperty =
            DependencyProperty.Register("SearchParam", typeof(string), typeof(SearchComboBox), new FrameworkPropertyMetadata(""));

        public System.Collections.IList SourceItems
        {
            get { return (System.Collections.IList)GetValue(SourceItemsProperty); }
            set { SetValue(SourceItemsProperty, value);  }
        }

        public static readonly DependencyProperty SourceItemsProperty =
            DependencyProperty.Register("SourceItems", typeof(System.Collections.IList), typeof(SearchComboBox), new PropertyMetadata(default(System.Collections.IList)));


        #endregion

        
        #region Constructors

        static SearchComboBox()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(SearchComboBox), new FrameworkPropertyMetadata(typeof(SearchComboBox)));
        }

        public SearchComboBox()
        {
            
        }
        
        #endregion //Constructors

        #region override
        protected override void OnLostMouseCapture(MouseEventArgs e)
        {
            if (Mouse.Captured == null)
            {
                if (e.OriginalSource == this)
                {
                    //SetPopupState();
                }
                else if (IsDropDownOpen)
                {
                    Mouse.Capture(this, CaptureMode.SubTree);
                }
            }

            base.OnLostMouseCapture(e);
        }

        /// <summary>
        /// Responds to a <see cref="T:System.Windows.Controls.ComboBox" /> selection change by raising a <see cref="E:System.Windows.Controls.Primitives.Selector.SelectionChanged" /> event.
        /// Change selection only on click on item
        /// </summary>
        /// <param name="e">Provides data for <see cref="T:System.Windows.Controls.SelectionChangedEventArgs" />.</param>
        protected override void OnSelectionChanged(SelectionChangedEventArgs e)
        {
            if (Editor == null || !Editor.IsKeyboardFocused || ( Editor.IsKeyboardFocused && _editorMouseLeaveFlag ) )
            {
                base.OnSelectionChanged(e);
                if (e.AddedItems.Count != 0 && SelectedIndex != this.SourceItems.IndexOf(e.AddedItems[0]))
                {
                        SelectedValue = e.AddedItems[0];
                }
            }
            e.Handled = true;
        }

       
        #endregion

        #region Initialization

        void InitSelectedList()
        {
            if (SearchItemsList == null)
            {
                SearchItemsList = new ListCollectionView(this.SourceItems);
                if (String.IsNullOrEmpty(SearchParam))
                    SearchItemsList.Filter = null;
                else
                {
                    SearchItemsList.Filter = (ob) =>
                    {
                        var prop = ob.GetType().GetProperty(SearchParam);
                        if (prop == null)
                        {
                            return true;
                        }
                        string value = prop.GetValue(ob, null) as string;
                        return value != null && (String.IsNullOrEmpty(SearchText) || value.ToLower().Contains(SearchText.ToLower()));
                    };
                }
                Binding mbinding = new Binding("SearchItems");
                mbinding.Mode = BindingMode.Default;
                mbinding.Source = this;
                mbinding.Path = new PropertyPath("SearchItemsList");
               
                SetBinding(ComboBox.ItemsSourceProperty, mbinding);
            }
        }
        /// <summary>
        /// When overridden in a derived class, is invoked whenever application code or internal processes call <see cref="M:System.Windows.FrameworkElement.ApplyTemplate" />.
        /// </summary>
        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();
           
            var binding1 = BindingOperations.GetBinding(this, ComboBox.ItemsSourceProperty);
            SetBinding(SearchComboBox.SourceItemsProperty, binding1);
            Popup = Template.FindName(PartPopup, this) as Popup;
           
            if (Popup != null)
            {
                Popup.StaysOpen = false;
                Popup.Opened += OnPopupOpened;
                Popup.Closed += OnPopupClosed;
                
            }
            Editor = Template.FindName(PartEditor, this) as TextBox;
            if(Editor != null)
            {
                Editor.TextChanged += OnEditorTextChanged;
                Editor.MouseLeave += Editor_MouseLeave;
                Editor.MouseEnter += Editor_MouseEnter;
            }
        }

        #endregion

        #region EventHandlers
        
        private void Popup_KeyDown(object sender, KeyEventArgs e)
        {
            if (Editor != null )
            {
                Editor.Focus();
                Keyboard.Focus(Editor);
            }
        }

        private void OnPopupOpened(object sender, EventArgs e)
        {
            SearchText = "";
            InitSelectedList();
            if (Editor != null )
            {
                Editor.Text = "";
                Editor.Focus();
                Editor.SelectionStart = 0;
                Keyboard.Focus(Editor);
            }
            _savedSelectedIndex = SelectedIndex;
        }

        /// <summary>
        /// Called when [popup closed].
        ///  Selection Index/Value will be set according to unfiltered whole list
        /// </summary>
        /// <param name="sender">The sender.</param>
        /// <param name="e">The <see cref="EventArgs"/> instance containing the event data.</param>
        private void OnPopupClosed(object sender, EventArgs e)
        {
           if(SelectedIndex == -1 && _savedSelectedIndex >=0)// selection item was set to null for filtering but not selected, return to prev value
            {
                SearchText = "";
                SearchItemsList.Refresh();
                SelectedValue = SearchItemsList.GetItemAt(_savedSelectedIndex);
            }
           if(this.SourceItems.Count != SearchItemsList.Count)//selection was changed on filtered list - replace to real selection index 
            {
                var selvalue = SelectedValue;
                SearchText = "";
                SearchItemsList.Refresh();
                SelectedValue = selvalue;
            }
            _savedSelectedIndex = -1;
        }

        private void OnEditorTextChanged(object sender, TextChangedEventArgs e)
        {
            if (FetchTimer == null)
            {
                FetchTimer = new DispatcherTimer();
                FetchTimer.Interval = TimeSpan.FromMilliseconds(100);
                FetchTimer.Tick += OnFetchTimerTick;
            }
           
            FetchTimer.IsEnabled = true;
            FetchTimer.Start();
        }
        
        private void Editor_MouseEnter(object sender, MouseEventArgs e)
        {
            _editorMouseLeaveFlag = false;
        }

        private void Editor_MouseLeave(object sender, MouseEventArgs e)
        {
            _editorMouseLeaveFlag = true;
        }
        
        private void OnFetchTimerTick(object sender, EventArgs e)
        {
            FetchTimer.IsEnabled = false;
            FetchTimer.Stop();
            SearchText = Editor.Text;
            OnTextChanged();
        }

        public virtual void OnTextChanged()
        {
           if (SearchItemsList != null)
            {
                SearchItemsList.Refresh();
            }
           if(SearchItemsList.Count > 0 && SelectedIndex != -1)
            {
                SelectedIndex = -1;// trick: all filtered items are displayed only with SelectedIndex = -1 , otherwise it is displayed 1 less 
            }
        }

        #endregion
    }
}