在WinForm的DataGrid中加入ComboBox

WinForm的DataGrid要显示ComboBox的效果必须要写一个继承自DataGridTextBoxColumn的类, 並在其中制作ComboBox的功能, 再把这个类的对象加入到DataGrid中使用即可, 做法如下:

DataGridComboBoxColumn ComboCol =new DataGridComboBoxColumn(); 
    ComboCol.MappingName = "RegionID";
    ComboCol.HeaderText = "Region";
    ComboCol.Width = 120;   ComboCol.ColumnComboBox.DataSource = ds1.Tables["Region"].DefaultView;
    ComboCol.ColumnComboBox.DisplayMember = "RegionDescription";
    ComboCol.ColumnComboBox.ValueMember = "RegionID";    tableStyle.PreferredRowHeight = ComboCol.ColumnComboBox.Height + 2;
    tableStyle.GridColumnStyles.Add(ComboCol);   dataGrid1.TableStyles.Add(tableStyle);

 

其中的DataGridComboBoxColumn的写法如下:

public class DataGridComboBoxColumn : DataGridTextBoxColumn
  {
   public NoKeyUpCombo ColumnComboBox;
   private System.Windows.Forms.CurrencyManager _source;
   private int _rowNum;
   private bool _isEditing;
   public static int _RowCount;
   
   public DataGridComboBoxColumn() : base()
   {
    _source = null;
    _isEditing = false;
    _RowCount = -1;
  
    ColumnComboBox = new NoKeyUpCombo();
    ColumnComboBox.DropDownStyle = ComboBoxStyle.DropDownList;
   
    ColumnComboBox.Leave += new EventHandler(LeaveComboBox);
    //  ColumnComboBox.Enter += new EventHandler(ComboMadeCurrent);
    ColumnComboBox.SelectionChangeCommitted += new EventHandler(ComboStartEditing);
   
   }
   private void ComboStartEditing(object sender, EventArgs e)
   {
    _isEditing = true;
    base.ColumnStartedEditing((Control) sender);
   }  private void HandleScroll(object sender, EventArgs e)
   {
    if(ColumnComboBox.Visible)
     ColumnComboBox.Hide();  }  
   private void LeaveComboBox(object sender, EventArgs e)
   {
    if(_isEditing)
    {
     SetColumnValueAtRow(_source, _rowNum, ColumnComboBox.Text);
     _isEditing = false;
     Invalidate();
    }
    ColumnComboBox.Hide();
    this.DataGridTableStyle.DataGrid.Scroll -= new EventHandler(HandleScroll);
    
   }  protected override void Edit(System.Windows.Forms.CurrencyManager source, int rowNum, System.Drawing.Rectangle bounds, bool readOnly, string instantText, bool cellIsVisible)
   {
       base.Edit(source,rowNum, bounds, readOnly, instantText , cellIsVisible);
   _rowNum = rowNum;
    _source = source;
   
    ColumnComboBox.Parent = this.TextBox.Parent;
    ColumnComboBox.Location = this.TextBox.Location;
    ColumnComboBox.Size = new Size(this.TextBox.Size.Width, ColumnComboBox.Size.Height);
    ColumnComboBox.SelectedIndex = ColumnComboBox.FindStringExact(this.TextBox.Text);
    ColumnComboBox.Text =  this.TextBox.Text;
    this.TextBox.Visible = false;
    ColumnComboBox.Visible = true;
    this.DataGridTableStyle.DataGrid.Scroll += new EventHandler(HandleScroll);
    
    ColumnComboBox.BringToFront();
    ColumnComboBox.Focus(); 
   }  protected override bool Commit(System.Windows.Forms.CurrencyManager dataSource, int rowNum)
   {
    if(_isEditing)
    {
     _isEditing = false;
     SetColumnValueAtRow(dataSource, rowNum, ColumnComboBox.Text);
    }
    return true;
   }  protected override void ConcedeFocus()
   {
    Console.WriteLine("ConcedeFocus");
    base.ConcedeFocus();
   }  protected override object GetColumnValueAtRow(System.Windows.Forms.CurrencyManager source, int rowNum)
   {   object s =  base.GetColumnValueAtRow(source, rowNum);
    DataView dv = (DataView)this.ColumnComboBox.DataSource;
    int rowCount = dv.Count;
    int i = 0;
    while (i < rowCount)
    {
     if( s.Equals( dv[i][this.ColumnComboBox.ValueMember]))
      break;
     ++i;
    }
    
    if(i < rowCount)
     return dv[i][this.ColumnComboBox.DisplayMember];
    
    return DBNull.Value;
   }  protected override void SetColumnValueAtRow(System.Windows.Forms.CurrencyManager source, int rowNum, object value)
   {
    object s = value;   DataView dv = (DataView)this.ColumnComboBox.DataSource;
    int rowCount = dv.Count;
    int i = 0;
    while (i < rowCount)
    {
     if( s.Equals( dv[i][this.ColumnComboBox.DisplayMember]))
      break;
     ++i;
    }
    if(i < rowCount)
     s =  dv[i][this.ColumnComboBox.ValueMember];
    else
     s = DBNull.Value;
    base.SetColumnValueAtRow(source, rowNum, s);  }
  }public class NoKeyUpCombo : ComboBox
  {
   private const int WM_KEYUP = 0x101;  protected override void WndProc(ref System.Windows.Forms.Message m)
   {
    if(m.Msg == WM_KEYUP)
    {
     return;
    }
    base.WndProc(ref m);
   }
  }