召集讨论 DataGridViewComboBoxColumn 可编辑/输入版本

Question

需求：DataGridViewComboBoxColumn 可编辑/输入版本。
实现方法：将EditingControl改成ComboBox，再输入完成和验证完成之间检查Items，如果不存在该值则插入。
本人目前搜集到的版本有两个。1.GetFormattedValue版本：http://blog.csdn.net/maji9370/archive/2009/09/16/4557770.aspx
2.OnEditingControlShowing版本：http://www.cnblogs.com/michaelhuwei/archive/2008/09/28/1301290.html就本人使用体验，
GetFormattedValue版本 将造成每次频繁触发GetFormattedValue事件（鼠标滑过该列、窗口重绘、单元格赋值等），如果在插入Items前还要处理（验证/修正）值则将明显造成显示刷新延迟，因为触发常常是整列每个单元格多次触发。
OnEditingControlShowing版本没有显示刷新延迟，因为只有在需要验证时才处理Items插入事件，缺点是每次进入编辑都要重载DorDownStyle，如果该Items.Count太大则进入编辑将有明显延迟（我的是123，延迟600毫秒左右）。论题：
看过VC（MFC）的类似实现并没有明显延迟，请试论C#是否能实现？

Answer 1

private void dataGridView1_EditingControlShowing(object sender,
    DataGridViewEditingControlShowingEventArgs e)
{
    ComboBox combo = e.Control as ComboBox;
    if (combo != null)
    {
        combo.SelectedIndexChanged +=
            new EventHandler(ComboBox_SelectedIndexChanged);
    }
}
private void ComboBox_SelectedIndexChanged(object sender, EventArgs e)
{
 ComboBox cb=(ComboBox)sender;
}
一般使用这个

Answer 2

Win or web?
以前好像写过一个DataGrid(VS03)版本的下拉框组件，并没什么明显刷新的现象啊。

Answer 3

貌似 SelectIndexChanged 比 EditingControlShowing早触发,实际运行效果是从一个TextBox列改选到ComboBox列不触发SelectIndexChanged ,要在ComboBox里切换单元格才会有效果。
我换用了Enter事件，结果每次进入（鼠标单击或设置为CurrentCell）都会触发两次，有延迟。

Answer 4

最新发现：
经过多次断点测试分析发现：combo.DropDownStyle = ComboBoxStyle.DropDown; //此处将重新触发Enter，在此之前需清除事件绑定。
目前延时100ms我的机器配置：E2180（双核 2.00GHz） 2.0GB内存 NVIDIA 8600GT 显卡
        EventHandler eventHandler;
        private void ChannelDgv_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
        {                ComboBox combo = e.Control as ComboBox;
                if (combo != null)
                {
                    if (eventHandler == null)
                    {
                        eventHandler  = new EventHandler(combo_Enter);
                        //eventHandler = new EventHandler(combo_SelectedIndexChanged);
                    }
                    //combo.SelectedIndexChanged += eventHandler;
                    combo.Enter -= eventHandler;   //取消可能的事件绑定
                    combo.Enter += eventHandler; //绑定事件
                }
        }
        void combo_Enter(object sender, EventArgs e)
        {
            DateTime st = DateTime.Now;            ComboBox combo = sender as ComboBox;
            if (combo != null)
            {
                combo.Enter -= eventHandler;   //取消事件绑定
                  combo.DropDownStyle = ComboBoxStyle.DropDown; //此处将重新触发Enter
                //cb.AutoCompleteMode = AutoCompleteMode.Suggest;
                combo.MaxLength = 5;
            }
            labTimeSpan.Text = (DateTime.Now - st).ToString();
        }

Answer 5

确实，经测试combo.DropDownStyle = ComboBoxStyle.DropDown;放在EditingControlShowing里和放在Enter或者其他事件里区别不大，之前看到的区别仅仅是因为我的机器状态不一样，早上刚开机就快得多...然则，即使快得多也还是显得慢，100毫秒的延迟是可视，如果不转换的话EditingControlShowing时间几乎为0。同时如果Items.Count == 1;时间约等于20毫秒,显然DropDownStyle改变时重载了Items。combo.DropDownStyle = ComboBoxStyle.DropDown; //100ms
cb.DropDownStyle = ComboBoxStyle.DropDownList; //0ms(默认属性，等于没改)
cb.DropDownStyle = ComboBoxStyle.Simple; //20ms由上时间可知时间花费应与下拉列表有关，仅仅是允许编辑花费的时间固定为20ms，其他时间用于下拉列表重新生成？Items内容并没有变更，有何办法避免这些时间花费？

Answer 6

using System; using WeifenLuo.WinFormsUI.Docking;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;namespace FisClient.NetborClass
{
    class Netbor
    {
    }
    public class DataGridViewComboBoxExEditingControl : ComboBox, IDataGridViewEditingControl
    {
        protected int rowIndex;
        protected DataGridView dataGridView;
        protected bool valueChanged = false;        protected override void OnTextChanged(System.EventArgs e)
        {
            base.OnTextChanged(e);
            NotifyDataGridViewOfValueChange();        }        private void NotifyDataGridViewOfValueChange()
        {
            valueChanged = true;
            dataGridView.NotifyCurrentCellDirty(true);
        }
        protected override void OnSelectedIndexChanged(EventArgs e)
        {
            base.OnTextChanged(e);
            NotifyDataGridViewOfValueChange();
        }        public Cursor EditingPanelCursor
        {
            get { return Cursors.IBeam; }
        }        public DataGridView EditingControlDataGridView
        {
            get { return dataGridView; }
            set { dataGridView = value; }
        }        public object EditingControlFormattedValue
        {
            set
            {
                Text = value.ToString();
                NotifyDataGridViewOfValueChange();
            }
            get
            {
                return this.Text;
            }        }        public virtual object GetEditingControlFormattedValue(DataGridViewDataErrorContexts context)
        {
            return Text;        }        public bool EditingControlWantsInputKey(Keys key, bool dataGridViewWantsInputKey)
        {            switch (key & Keys.KeyCode)
            {
                case Keys.Left:
                case Keys.Up:
                case Keys.Down:
                case Keys.Right:
                case Keys.Home:
                case Keys.End:
                case Keys.Escape:
                case Keys.Enter:
                case Keys.PageDown:
                case Keys.PageUp:
                    return true;
                default:
                    return false;
            }
        }        public void PrepareEditingControlForEdit(bool selectAll)
        {
            if (selectAll)
            {
                SelectAll();
            }
            else
            {
                this.SelectionStart = this.ToString().Length;
            }
        }
        public virtual bool RepositionEditingControlOnValueChange
        {
            get
            {
                return false;
            }
        }        public int EditingControlRowIndex
        {
            get { return this.rowIndex; }
            set { this.rowIndex = value; }
        }        public void ApplyCellStyleToEditingControl(DataGridViewCellStyle dataGridViewCellStyle)
        {
            this.Font = dataGridViewCellStyle.Font;
            this.ForeColor = dataGridViewCellStyle.ForeColor;
            this.BackColor = dataGridViewCellStyle.BackColor;
        }        public bool EditingControlValueChanged
        {
            get { return valueChanged; }
            set { this.valueChanged = value; }
        }
    }    //定制该扩展列的单元格
    public class DataGridViewComboBoxExCell : DataGridViewTextBoxCell
    {
        public override void InitializeEditingControl(int rowIndex, object initialFormattedValue, DataGridViewCellStyle dataGridViewCellStyle)
        {
            base.InitializeEditingControl(rowIndex, initialFormattedValue, dataGridViewCellStyle);            DataGridViewComboBoxExEditingControl clt = DataGridView.EditingControl as DataGridViewComboBoxExEditingControl;            DataGridViewComboBoxExColumn col = (DataGridViewComboBoxExColumn)OwningColumn;            clt.DataSource = col.DataSource;
            clt.DisplayMember = col.DisplayMember;
            clt.ValueMember = col.ValueMember;            clt.Text = Convert.ToString(this.Value);
        }        public override Type EditType
        {
            get
            {
                return typeof(DataGridViewComboBoxExEditingControl);
            }
        }        public override Type ValueType
        {
            get
            {
                return typeof(string);
            }
        }        public override object DefaultNewRowValue
        {
            get
            {
                return "";
            }
        }
    }    //定制该扩展列
    public class DataGridViewComboBoxExColumn : DataGridViewColumn
    {
        private object dataSoruce = null;        public object DataSource
        {
            get 
            { 
                return dataSoruce; 
            }
            set 
            { 
                dataSoruce = value; 
            }
        }
        private string valueMember;        public string ValueMember
        {
            get 
            { 
                return valueMember;
            }
            set 
            { 
                valueMember = value; 
            }
        }
        private string displayMember;        public string DisplayMember
        {
            get 
            { 
                return displayMember; 
            }
            set 
            { 
                displayMember = value; 
            }
        }        public DataGridViewComboBoxExColumn() : base(new DataGridViewComboBoxExCell())
        {        }        public override DataGridViewCell CellTemplate
        {
            get
            {
                return base.CellTemplate;
            }
            set
            {
                if (value != null && !value.GetType().IsAssignableFrom(typeof(DataGridViewComboBoxExCell)))
                {
                    throw new InvalidCastException("is not DataGridViewComboxExCell");
                }
                base.CellTemplate = value;
            }
        }
        private DataGridViewComboBoxExCell ComboBoxCellTemplate
        {
            get
            {
                return (DataGridViewComboBoxExCell)this.CellTemplate;
            }
        }
    }
    //另一个Combox
    public class DataGridViewComboEditBoxCell : DataGridViewComboBoxCell
    {
        public override void InitializeEditingControl(int rowIndex, object initialFormattedValue, DataGridViewCellStyle dataGridViewCellStyle)
        {
            base.InitializeEditingControl(rowIndex, initialFormattedValue, dataGridViewCellStyle);            ComboBox comboBox = base.DataGridView.EditingControl as ComboBox;
            if (comboBox != null)
            {
                comboBox.DropDownStyle = ComboBoxStyle.DropDown;
                comboBox.Validating += new CancelEventHandler(comboBox_Validating);
            }
        }        protected override object GetFormattedValue(object value, int rowIndex, ref DataGridViewCellStyle cellStyle, TypeConverter valueTypeConverter, TypeConverter formattedValueTypeConverter, DataGridViewDataErrorContexts context)
        {
            if (value != null)
            {
                if (value.ToString().Trim() != string.Empty)
                {
                    if (Items.IndexOf(value) == -1)
                    {
                        Items.Add(value);
                        DataGridViewComboBoxColumn col = OwningColumn as DataGridViewComboBoxColumn;
                        col.Items.Add(value);
                    }
                }
            }
            return base.GetFormattedValue(value, rowIndex, ref cellStyle, valueTypeConverter, formattedValueTypeConverter, context);
        }        void comboBox_Validating(object sender, System.ComponentModel.CancelEventArgs e)
        {
            DataGridViewComboBoxEditingControl cbo = sender as DataGridViewComboBoxEditingControl;
            if (cbo.Text.Trim() == string.Empty) return;            DataGridView grid = cbo.EditingControlDataGridView;
            object value = cbo.Text;
            // Add value to list if not there            if (cbo.Items.IndexOf(value) == -1)
            {
                DataGridViewComboBoxColumn cboCol = grid.Columns[grid.CurrentCell.ColumnIndex] as DataGridViewComboBoxColumn;
                // Must add to both the current combobox as well as the template, to avoid duplicate entries
                cbo.Items.Add(value);
                cboCol.Items.Add(value);
                grid.CurrentCell.Value = value;
            }
        }
    }    public class DataGridViewComboEditBoxColumn : DataGridViewComboBoxColumn
    {
        public DataGridViewComboEditBoxColumn()
        {
            DataGridViewComboEditBoxCell obj = new DataGridViewComboEditBoxCell();
            this.CellTemplate = obj;
        }
    }
}