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三个属性注意

this.StaysOpenOnEdit = true 

this.IsEditable = true

this.IsTextSearchEnabled = false//自带的自动完成

 

 

第一种：简单的。

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Windows;using System.Windows.Controls;using System.Windows.Input;namespace GEMS.Windows.Controls.CustomControls{    public class SimpleAutoCompleteComboBox : ComboBox    {        static SimpleAutoCompleteComboBox()        {            DefaultStyleKeyProperty.OverrideMetadata(typeof(SimpleAutoCompleteComboBox), new FrameworkPropertyMetadata(typeof(SimpleAutoCompleteComboBox)));        }        public SimpleAutoCompleteComboBox()        {            this.StaysOpenOnEdit = true;            this.IsEditable = true;            this.IsTextSearchEnabled = true;            this.LostFocus += SimpleAutoCompleteComboBox_LostFocus;        }        public override void OnApplyTemplate()        {            base.OnApplyTemplate();            //load the text box control            if (this.EditableTextBox != null)            {               // this.EditableTextBox.PreviewKeyDown += new KeyEventHandler(EditableTextBox_PreviewKeyDown);                this.EditableTextBox.TextChanged += new TextChangedEventHandler(EditableTextBox_TextChanged);            }        }        //void EditableTextBox_PreviewKeyDown(object sender, KeyEventArgs e)        //{        //    this.IsKeyEvent = true;        //}        void EditableTextBox_TextChanged(object sender, TextChangedEventArgs e)        {            if ( this.EditableTextBox.IsFocused)                        {                this.IsDropDownOpen = true;            }                   }        /// 
        /// Gets the text box in charge of the editable portion of the combo box.        /// 
        protected TextBox EditableTextBox        {            get            {                return base.GetTemplateChild("PART_EditableTextBox") as TextBox;            }        }        private string SelectedText        {            get            {                if (this.SelectedIndex == -1) return string.Empty;                return this.SelectedItem.GetType().GetProperty(this.DisplayMemberPath).GetValue(this.SelectedItem, null).ToString();            }        }        void SimpleAutoCompleteComboBox_LostFocus(object sender, RoutedEventArgs e)        {            this.IsDropDownOpen = false;            // to prevent misunderstanding that user has entered some information            if (this.SelectedIndex == -1)            {                this.Text = null;                this.SelectedItem = null;                this.SelectedValue = null;            }            // syncronize text            else                this.Text = this.SelectedText;            // release timer resources                       try            {                this.EditableTextBox.CaretIndex = 0;            }            catch { }        }    }}

 

第2种：下拉只显示关联的

using System;using System.Collections;using System.Collections.Generic;using System.Collections.ObjectModel;using System.ComponentModel;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Timers;using System.Windows;using System.Windows.Controls;using System.Windows.Input;namespace GEMS.Windows.Controls.CustomControls{    public class AutoCompleteComboBox : ComboBox    {        #region Fields        private Timer _interval;        private int _maxRecords = 10;        private bool _typeAhead = false;        private bool IsKeyEvent = false;        private bool _clearOnEmpty = true;        private int _delay = DEFAULT_DELAY;        private const int DEFAULT_DELAY = 500;        private ObservableCollection
      
        CurrentItems;        #endregion        #region properties        [DefaultValue(DEFAULT_DELAY)]        public int Delay        {            get            {                return this._delay;            }            set            {                this._delay = value;            }        }        public bool ClearOnEmpty        {            get            {                return this._clearOnEmpty;            }            set            {                this._clearOnEmpty = true;            }        }        /// 
       
        /// Gets the text box in charge of the editable portion of the combo box.        /// 
        protected TextBox EditableTextBox        {            get            {                return base.GetTemplateChild("PART_EditableTextBox") as TextBox;            }        }        private string SelectedText        {            get            {                if (this.SelectedIndex == -1) return string.Empty;                return this.SelectedItem.GetType().GetProperty((string.IsNullOrWhiteSpace(this.SearchBy) ? this.DisplayMemberPath : this.SearchBy)).GetValue(this.SelectedItem, null).ToString();            }        }        #endregion        #region DependencyProperty        public static readonly DependencyProperty DataSourceProperty =            DependencyProperty.Register("DataSource", typeof(IEnumerable), typeof(AutoCompleteComboBox), new PropertyMetadata(null, new PropertyChangedCallback(OnDataSourceChanged)));        private static void OnDataSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)        {            AutoCompleteComboBox autoCompleteComboBox = (AutoCompleteComboBox)d;            autoCompleteComboBox.ItemsSource = (IEnumerable)e.NewValue;        }        public IEnumerable DataSource        {            get            {                return base.GetValue(AutoCompleteComboBox.DataSourceProperty) as IEnumerable;            }            set            {                base.SetValue(AutoCompleteComboBox.DataSourceProperty, value);            }        }        public string SearchBy        {            get { return (string)GetValue(SearchByProperty); }            set { SetValue(SearchByProperty, value); }        }        // Using a DependencyProperty as the backing store for SearchBy.  This enables animation, styling, binding, etc...        public static readonly DependencyProperty SearchByProperty =            DependencyProperty.Register("SearchBy", typeof(string), typeof(AutoCompleteComboBox), new PropertyMetadata(null));        #endregion        public override void OnApplyTemplate()        {            base.OnApplyTemplate();            //load the text box control            if (this.EditableTextBox != null)            {                this.EditableTextBox.PreviewKeyDown += new KeyEventHandler(EditableTextBox_PreviewKeyDown);                this.EditableTextBox.TextChanged += new TextChangedEventHandler(EditableTextBox_TextChanged);            }        }        static AutoCompleteComboBox()        {            DefaultStyleKeyProperty.OverrideMetadata(typeof(AutoCompleteComboBox), new FrameworkPropertyMetadata(typeof(AutoCompleteComboBox)));        }        public AutoCompleteComboBox()        {            CurrentItems = new ObservableCollection
       
        ();            if (!DesignerProperties.GetIsInDesignMode(this))            {                this._interval = new Timer(this.Delay);                this._interval.AutoReset = true;                this._interval.Elapsed += new ElapsedEventHandler(_interval_Elapsed);            }            this.Loaded += AutoCompleteComboBox_Loaded;            this.LostFocus += AutoCompleteComboBox_LostFocus;            this.SelectionChanged += AutoCompleteComboBox_SelectionChanged;            this.StaysOpenOnEdit = true;            this.IsEditable = true;            this.IsTextSearchEnabled = false;        }        private void AutoCompleteComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)        {            this._interval.Stop();        }        void AutoCompleteComboBox_LostFocus(object sender, RoutedEventArgs e)        {            this.IsKeyEvent = false;            this.IsDropDownOpen = false;            // to prevent misunderstanding that user has entered some information            if (this.SelectedIndex == -1)            {                this.Text = null;                this.SelectedItem = null;                this.SelectedValue = null;            }            // syncronize text            else                this.Text = this.SelectedText;            // release timer resources            this._interval.Close();            try            {                this.EditableTextBox.CaretIndex = 0;            }            catch { }        }        void AutoCompleteComboBox_Loaded(object sender, RoutedEventArgs e)        {            this.ItemsSource = this.DataSource;        }        #region MyRegion        void _interval_Elapsed(object sender, ElapsedEventArgs e)        {            IsKeyEvent = false;            // pause the timer            this._interval.Stop();            // show the drop down when user starts typing then stops            this.Dispatcher.BeginInvoke((Action)delegate            {                // load from event source                this.CurrentItems = new ObservableCollection
        
         ();                if (this.Text.Length >= 0)                {                    foreach (var entry in DataSource)                    {                        string SearchName = entry.GetType().GetProperty((string.IsNullOrWhiteSpace(this.SearchBy) ? this.DisplayMemberPath : this.SearchBy)).GetValue(entry, null).ToString().ToUpper();                        if (SearchName.StartsWith(this.Text.ToUpper(), StringComparison.CurrentCultureIgnoreCase))                        {                            CurrentItems.Add(entry);                        }                    }                    this.ItemsSource = CurrentItems;                    this.IsDropDownOpen = this.HasItems;                }                else                {                    this.IsDropDownOpen = false;                }            },                System.Windows.Threading.DispatcherPriority.ApplicationIdle);        }        #endregion        #region EditableTextBoxEvent        void EditableTextBox_PreviewKeyDown(object sender, KeyEventArgs e)        {            this.IsKeyEvent = true;        }        void EditableTextBox_TextChanged(object sender, TextChangedEventArgs e)        {            if ( this.EditableTextBox.IsFocused)            {                if (this.ClearOnEmpty && string.IsNullOrEmpty(this.EditableTextBox.Text.Trim()))                    this.ItemsSource = this.DataSource;                else if (IsKeyEvent)                    this.ResetTimer();            }                  }        protected void ResetTimer()        {            this._interval.Stop();            this._interval.Start();        }        #endregion    }}