WinForm 自动完成控件

在Web的应用方面有js的插件实现自动完成（或叫智能提示）功能，但在WinForm窗体应用方面就没那么好了。

TextBox控件本身是提供了一个自动提示功能，只要用上这三个属性：

AutoCompleteCustomSource：AutoCompleteSource 属性设置为CustomSource 时要使用的 StringCollection。

AutoCompleteMode： 指示文本框的文本完成行为。

AutoCompleteSource：自动完成源，可以是 AutoCompleteSource 的枚举值之一。

就行了， 一个简单的示例如下

textBox1.AutoCompleteCustomSource .AddRange(new string[] { "java","javascript","js","c#","c","c++" });
textBox1.AutoCompleteMode = AutoCompleteMode.SuggestAppend;
textBox1.AutoCompleteSource = AutoCompleteSource.CustomSource;

 可是这种方式的不支持我们中文的简拼自动完成（如在文本框里输入"gz"就会出现"广州"）。只好自己写一个支持简拼自动完成的控件了。

这是效果图

控件不太复杂，一个TextBox和一个ListBox。代码方面，用DataTable作数据源，每次在TextBox的值时，通过DataTable的Select方法，配上合适的表达式(如：{0} like '{1}%' and IsNull([{2}], ' ') <> ' ')来筛选出合适的备选文本内容，以下则是控件的代码：

        private TextBox _tb;
        private ListBox _lb;
        private DataTable _dt_datasource;
        private bool _text_lock;
        private string _general_text;//原始输入文本框的值
        private bool _lb_kd_first_top;//listbox是否第一次到达顶部
        private int _itemCount;

        /// <summary>
        /// TextBox的Text属性，增加了_text_lock操作，放置触发TextChanged事件
        /// </summary>
        private string TextBoxText 
        {
            get { return _tb.Text; }
            set
            {
                _text_lock = true;
                _tb.Text = value;
                _text_lock = false;
            }
        }

        /// <summary>
        /// 显示在ListBox的字段名
        /// </summary>
        public string ValueName { get; set; }

        /// <summary>
        /// 用于匹配的字段名
        /// </summary>
        public string CodeName { get; set; }

        /// <summary>
        /// 显示提示项的数量
        /// </summary>
        public int ItemCount
        {
            get
            { return _itemCount; }
            set
            {
                if (value <= 0)
                    _itemCount = 1;
                else
                    _itemCount = value;
            }
        }

        public DataTable DataSource
        {
            get { return _dt_datasource; }
            set { _dt_datasource = value; }
        }

        public AutoComplete()
        {
            InitialControls();
        }

        void AutoComplete_Load(object sender, EventArgs e)
        {
            _tb.Width = this.Width;
            _lb.Width = _tb.Width;
            this.Height = _tb.Height-1;
        }

        void AutoComplete_LostFocus(object sender, EventArgs e)
        {
            _lb.Visible = false;
            this.Height = _tb.Height-1;
        }

        //列表框按键事件
        void _lb_KeyDown(object sender, KeyEventArgs e)
        {
            if (_lb.Items.Count == 0 || !_lb.Visible) return;

            if (!_lb_kd_first_top && ((e.KeyCode == Keys.Up && _lb.SelectedIndex == 0) || (e.KeyCode == Keys.Down && _lb.SelectedIndex == _lb.Items.Count)))
            {
                _lb.SelectedIndex = -1;
                TextBoxText = _general_text;
            }
            else
            {
                TextBoxText = ((DataRowView)_lb.SelectedItem)[ValueName].ToString();
                _lb_kd_first_top = _lb.SelectedIndex != 0;
            }

            if (e.KeyCode == Keys.Enter && _lb.SelectedIndex != -1)
            {
                _lb.Visible = false;
                this.Height = _tb.Height;
                _tb.Focus();
            }
        }

        //列表鼠标单击事件
        void _lb_Click(object sender, EventArgs e)
        {
            if (_lb.SelectedIndex != -1)
            {
                TextBoxText = ((DataRowView)_lb.SelectedItem)[ValueName].ToString();
            }
            _lb.Visible = false;
            _tb.Focus();
            this.Height = _tb.Height;
        }

        //文本框按键事件
        void _tb_KeyDown(object sender, KeyEventArgs e)
        {
            if (_lb.Items.Count == 0||!_lb.Visible) return;

            bool _is_set = false;

            if (e.KeyCode == Keys.Up)
            {
                if (_lb.SelectedIndex <= 0)
                {
                    _lb.SelectedIndex = -1;
                    TextBoxText = _general_text;
                }
                else
                {
                    _lb.SelectedIndex--;
                    _is_set = true;
                }
            }
            else if (e.KeyCode == Keys.Down)
            {
                if (_lb.SelectedIndex == _lb.Items.Count - 1)
                {
                    _lb.SelectedIndex = 0; 
                    _lb.SelectedIndex = -1;
                    TextBoxText = _general_text;
                }
                else
                {
                    _lb.SelectedIndex++;
                    _is_set = true;
                }
            }
            else if (e.KeyCode == Keys.Enter)
            {
                _lb.Visible = false;
                this.Height = _tb.Height;
                _is_set = _lb.SelectedIndex != -1;
            }

            _lb_kd_first_top = _lb.SelectedIndex != 0;
            if (_is_set)
            { 
                _text_lock = true;
                _tb.Text = ((DataRowView)_lb.SelectedItem)[ValueName].ToString();
                _tb.SelectionStart = _tb.Text.Length + 10;
                _tb.SelectionLength = 0;
                _text_lock = false;
            }
        }

        //文本框文本变更事件
        void _tb_TextChanged(object sender, EventArgs e)
        {
            if (_text_lock) return;
            _general_text = _tb.Text;
            _lb.Visible = true;
            _lb.Height = _lb.ItemHeight * (_itemCount+1);
            this.BringToFront();
            _lb.BringToFront();
            this.Height = _tb.Height + _lb.Height;

            DataTable temp_table = _dt_datasource.Clone();
            string filtStr = FormatStr(_tb.Text);
            DataRow [] rows = _dt_datasource.Select(string.Format(GetFilterStr(),CodeName,filtStr,_lb.DisplayMember));
            for (int i = 0; i < rows.Length&&i<_itemCount; i++)
            {
                temp_table.Rows.Add(rows[i].ItemArray);
            }
            _lb.DataSource = temp_table;
            if (_lb.Items.Count > 0) _lb.SelectedItem = _lb.Items[0];
        }

        /// <summary>
        /// 初始化控件
        /// </summary>
        private void InitialControls()
        {
            _lb_kd_first_top = true;

            _tb = new TextBox();
            _tb.Location = new Point(0, 0);
            _tb.Margin = new System.Windows.Forms.Padding(0);
            _tb.Width = this.Width;
            _tb.TextChanged += new EventHandler(_tb_TextChanged);
            _tb.KeyUp += new KeyEventHandler(_tb_KeyDown);

            _lb = new ListBox();
            _lb.Visible = false;
            _lb.Width = _tb.Width;
            _lb.Margin = new System.Windows.Forms.Padding(0);
            _lb.DisplayMember = ValueName;
            _lb.SelectionMode = SelectionMode.One;
            _lb.Location = new Point(0, _tb.Height);
            _lb.KeyUp += new KeyEventHandler(_lb_KeyDown);
            _lb.Click += new EventHandler(_lb_Click);

            this.Controls.Add(_tb);
            this.Controls.Add(_lb);
            this.Height = _tb.Height - 1;
            this.LostFocus += new EventHandler(AutoComplete_LostFocus);
            this.Leave += new EventHandler(AutoComplete_LostFocus);
            this.Load += new EventHandler(AutoComplete_Load);
        }

        /// <summary>
        /// 获取过滤格式字符串
        /// </summary>
        /// <returns></returns>
        private string GetFilterStr()
        {
            //未过滤注入的字符 ' ] %任意  *任意
            string filter = " {0} like '{1}%' and IsNull([{2}], ' ') <> ' '  ";
            if (_dt_datasource.Rows[0][CodeName].ToString().LastIndexOf(';') > -1)
                filter = " {0} like '%;{1}%' and IsNull([{2}],' ') <> ' ' ";

            return filter;
        }

        /// <summary>
        /// 过滤字符串中一些可能造成出错的字符
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        private string FormatStr(string str)
        {
            if (string.IsNullOrEmpty(str)) return string.Empty;
            str = str.Replace("[", "[[]").Replace("%", "[%]").Replace("*", "[*]").Replace("'", "''");
            if (CodeName == "code") str = str.Replace(" ", "");
            return str;
        }

下面是使用控件的例子

          class Common
    {
        /// <summary>
        /// 生成测试数据源
        /// </summary>
        public static DataTable CreateTestDataSoucre
        {
            get
            {
                List<KeyValuePair<string, string>> source = new List<KeyValuePair<string, string>>() 
                {
                    new KeyValuePair<string,string>("张三",";zs;张三;"),
                    new KeyValuePair<string,string>("李四",";li;李四;"),
                    new KeyValuePair<string,string>("王五",";ww;王五;"),
                    new KeyValuePair<string,string>("赵六",";zl;赵六;"),
                    new KeyValuePair<string,string>("洗刷",";cs;csharp;c#;洗刷;"),
                    new KeyValuePair<string,string>("爪哇",";java;爪哇;"),
                    new KeyValuePair<string,string>("java",";java;"),
                    new KeyValuePair<string,string>("c#",";c#;cs;csharp;"),
                    new KeyValuePair<string,string>("javascript",";javascript;js;")
                };

                DataTable table = new DataTable();

                table.Columns.Add("id");
                table.Columns.Add("name");
                table.Columns.Add("code");

                for (int i = 0; i < source.Count; i++)
                {
                    DataRow row = table.Rows.Add();
                    row["id"] = i;
                    row["name"] = source[i].Key;
                    row["code"] = source[i].Value;
                }

                return table;
            }
        }
    } 

             //.............
             AutoComplete ac=new AutoComplete();
            ac.ValueName = "name";
            ac.CodeName = "code";
            ac.DataSource= Common.CreateTestDataSoucre;
            ac.ItemCount= 5;