Winform下的Datagrid的列风格(4)—DataGridComboBoxTableViewColumn

class  DataGridComboBoxTableViewColumn: DataGridColumnStyle 
     {//与DataGridComboBoxColumn不同，显示时使用DataTable，下拉时使用DataView
         private ComboBox myComboBox = new ComboBox ();
         private DataView ChoiceDataViewSource;
         private DataView TableDataViewSource;
         private string ChoiceDisplayField;
         private string ChoiceValueField;
         private bool isEditing;        public DataGridComboBoxTableViewColumn(DataView ChoiceDataViewSource,string ChoiceDisplayField,string ChoiceValueField) : base() 
         {
             this.ChoiceDataViewSource =ChoiceDataViewSource;
             TableDataViewSource=new System.Data .DataView (ChoiceDataViewSource.Table);
             this.ChoiceDisplayField =ChoiceDisplayField;
             this.ChoiceValueField =ChoiceValueField;
             myComboBox.DropDownStyle =System.Windows .Forms .ComboBoxStyle .DropDownList  ;
             myComboBox.Visible = false;
             myComboBox.DataSource =this.ChoiceDataViewSource;
             myComboBox.DisplayMember= this.ChoiceDisplayField;
             myComboBox.ValueMember =this.ChoiceValueField;
         }
         protected override void Abort(int rowNum)
         {
             isEditing = false;
             myComboBox.SelectedIndexChanged -= 
                 new EventHandler(ComboBoxSelectedIndexChanged );
             Invalidate();
         }        protected override bool Commit
             (CurrencyManager dataSource, int rowNum) 
         {
             myComboBox.Bounds = Rectangle.Empty;
          
             myComboBox.SelectedIndexChanged -= 
                 new EventHandler(ComboBoxSelectedIndexChanged );            if (!isEditing)
                 return true;            isEditing = false;
            try 
             {
                 System.Object  value = myComboBox.SelectedValue;
                 SetColumnValueAtRow(dataSource, rowNum, value);
             } 
             catch (Exception) 
             {
                 Abort(rowNum);
                 return false;
             }            Invalidate();
             return true;
         }        protected override void Edit(
             CurrencyManager source, 
             int rowNum,
             Rectangle bounds, 
             bool readOnly,
             string instantText, 
             bool cellIsVisible) 
         {
             object value =GetColumnValueAtRow(source, rowNum);
             if (cellIsVisible) 
             {
                 myComboBox.Bounds = new Rectangle
                     (bounds.X + 2, bounds.Y + 2, 
                     bounds.Width - 4, bounds.Height - 4);
                 int i=    Find (value);
                 if (myComboBox.Items .Count >i)
                 {
                     myComboBox.SelectedIndex =i;
                 }
                 myComboBox.Visible = true;
                 myComboBox.SelectedIndexChanged += 
                     new EventHandler(ComboBoxSelectedIndexChanged );
             } 
             else 
             {
                 myComboBox.SelectedIndex =this.Find (value);
                 myComboBox.Visible = false;
             }            if (myComboBox.Visible)
                 DataGridTableStyle.DataGrid.Invalidate(bounds);
         }
         protected int Find(System.Object value)
         {
             int int1;
             int int2;
             
             int2=TableDataViewSource.Count ;
             if (int2<=0)
             {
                 return -1;
             }
             for (int1=0;int1<int2;int1++)
             {
                 if (TableDataViewSource[int1][this.myComboBox .ValueMember ].ToString ().Trim ()==value.ToString ().Trim ())
                 {
                     return int1;
                 }
             }
             return -1;
         }        protected override Size GetPreferredSize(
             Graphics g, 
             object value) 
         {
             return new Size(100, myComboBox.PreferredHeight+ 4);
         }        protected override int GetMinimumHeight() 
         {
             return myComboBox.PreferredHeight + 4;
         }        protected override int GetPreferredHeight(Graphics g, 
             object value) 
         {
             return myComboBox.PreferredHeight + 4;
         }        protected override void Paint(Graphics g, 
             Rectangle bounds, 
             CurrencyManager source, 
             int rowNum) 
         {
             Paint(g, bounds, source, rowNum, false);
         }
         protected override void Paint(
             Graphics g, 
             Rectangle bounds,
             CurrencyManager source, 
             int rowNum,
             bool alignToRight) 
         {
             Paint(
                 g,bounds, 
                 source, 
                 rowNum, 
                 , 
                 Brushes.Blue, 
                 alignToRight);
         }
         protected override void Paint(
             Graphics g, 
             Rectangle bounds,
             CurrencyManager source, 
             int rowNum,
             Brush backBrush, 
             Brush foreBrush,
             bool alignToRight) 
         {
             object value=GetColumnValueAtRow(source, rowNum);
             int int1=Find (value);
             string display="";
             if (int1>=0)
             {
                 display=this.TableDataViewSource [int1][this.myComboBox .DisplayMember ].ToString ();
             }
             Rectangle rect = bounds;
             g.FillRectangle(backBrush,rect);
             rect.Offset(0, 2);
             rect.Height -= 2;
             g.DrawString(display, 
                 this.DataGridTableStyle.DataGrid.Font, 
                 foreBrush, rect);
         }        protected override void SetDataGridInColumn(DataGrid value) 
         {
             base.SetDataGridInColumn(value);
             if (myComboBox.Parent != null) 
             {
                 myComboBox.Parent.Controls.Remove 
                     (myComboBox);
             }
             if (value != null) 
             {
                 value.Controls.Add(myComboBox);
             }
         }        private void ComboBoxSelectedIndexChanged(object sender, EventArgs e) 
         {
             this.isEditing = true;
             base.ColumnStartedEditing(myComboBox);
         }
     }