ComboBox in DataGrid

[Raimund]

Hallo
ich versuche grade eine ComboBox in ein DataGrid zubekommen

Ich habe im Netz diesen Code dazu gefunden.

Die Class

unit gDataGridComboBoxColumnU;

interface

uses
  System.Windows.Forms, System.Drawing, System.Data;

type

  DataGridComboBoxColumn = class(System.Windows.Forms.DataGridTextBoxColumn)

  private

    { Private-Deklarationen }

    cm: CurrencyManager;

    intCurrentRow: Integer;

    cbb: Combobox; // Hosted combobox control

    procedure comboBox_Leave(sender: System.Object; e: EventArgs );

    procedure DataGrid_Scroll(sender: System.Object; e: EventArgs);

  protected

    procedure Edit(source: System.Windows.Forms.CurrencyManager;

      rowNum: Integer; bounds: System.Drawing.Rectangle; readOnly: Boolean;

      instantText: string; cellIsVisible: Boolean); override;

    function GetColumnValueAtRow(source:
System.Windows.Forms.CurrencyManager;

      rowNum: Integer): System.Object; override;

    procedure SetColumnValueAtRow(source:
System.Windows.Forms.CurrencyManager;

      rowNum: Integer; value: System.Object); override;

  public

    constructor Create;

    function Combobx: Combobox;

  end;

 

implementation

 

constructor DataGridComboBoxColumn.Create;

{Constructor - create combobox, register selection change event handler,

register lose focus event handler}

begin

  inherited Create;

 

  // Create combobox and force DropDownList style:

  cbb := Combobox.Create;

  cbb.DropDownStyle := ComboBoxStyle.DropDownList;

 

  // Add event handler for notification when combobox loses focus:

  Include(Self.cbb.Leave, Self.comboBox_Leave);

end;

 

function DataGridComboBoxColumn.Combobx: Combobox;

begin

  Result := cbb;

end;

 

procedure DataGridComboBoxColumn.comboBox_Leave(sender: System.Object; e:
EventArgs );

{On combobox losing focus, set the column value, hide the combobox,

and unregister scroll event handler}

var

  str: string;

  rowView: DataRowView;

begin

  rowView := DataRowView(cbb.SelectedItem);

  str := string(rowView.Row[cbb.DisplayMember]);

 

  SetColumnValueAtRow(cm, intCurrentRow, str);

  Invalidate;

 

  cbb.Hide;

  Exclude(DataGridTableStyle.DataGrid.Scroll, DataGrid_Scroll);

end;

 

procedure DataGridComboBoxColumn.Edit(source:
System.Windows.Forms.CurrencyManager;

  rowNum: Integer; bounds: System.Drawing.Rectangle; readOnly: Boolean;

  instantText: string; cellIsVisible: Boolean);

// On edit, add scroll event handler, and display combobox

var rect: Rectangle;

begin

  inherited Edit(source, rowNum, bounds, readOnly, instantText,

    cellIsVisible);

 

  if (not readOnly and cellIsVisible) then

  begin

    // Save current row in the DataGrid and currency manager

    // associated with the data source for the DataGrid

    intCurrentRow := rowNum;

    cm := source;

 

    // Add event handler for DataGrid scroll notification

    include(DataGridTableStyle.DataGrid.Scroll, DataGrid_Scroll);

 

    // Site the combobox control within the current cell

    cbb.Parent := TextBox.Parent;

    rect := DataGridTableStyle.DataGrid.GetCurrentCellBounds;

    cbb.Location := rect.Location;

    cbb.Size := Size.Create(TextBox.Size.Width, cbb.Size.Height);

 

    // Set combobox selection to given text

    cbb.SelectedIndex := cbb.FindStringExact(TextBox.Text);

 

    // Make the combobox visible and place on top textbox control

    cbb.Show;

    cbb.BringToFront;

    cbb.Focus;

  end;

end;

 

function DataGridComboBoxColumn.GetColumnValueAtRow(

  source: System.Windows.Forms.CurrencyManager; rowNum: Integer):
System.Object;

{Given a row, get the value member associated with a row.  Use the

value member to find the associated display member by iterating

over bound data source}

var

  obj: System.&Object;

  dv: DataView;

  i: Integer;

begin

  // Given a row number in the DataGrid, get the display member

  obj := inherited GetColumnValueAtRow(source, rowNum);

 

  // Iterate through the data source bound to the ColumnComboBox

  cm :=
CurrencyManager(DataGridTableStyle.DataGrid.BindingContext[cbb.DataSource]);

  // Assumes the associated DataGrid is bound to a DataView or

  // DataTable

  dv := DataView(cm.List);

 

  for i := 0 to dv.Count - 1 do

    if (obj.Equals(dv[i][cbb.ValueMember])) then

      break;

  // If set item was found return corresponding value,

  // otherwise return DbNull.Value

  if (i < dv.Count) then

    Result := dv[i][cbb.DisplayMember];

  Result := DBNull.Value;

end;

 

procedure DataGridComboBoxColumn.SetColumnValueAtRow(

  source: System.Windows.Forms.CurrencyManager; rowNum: Integer;

  value: System.Object);

{Given a row and a display member, iterate over bound data source to

find the associated value member.  Set this value member.}

var

  s: System.&Object;

  dv: DataView;

  i: Integer;

begin

  s := value;

 

  // Iterate through the data source bound to the ColumnComboBox:

  cm := CurrencyManager(

    DataGridTableStyle.DataGrid.BindingContext[cbb.DataSource]);

  // Assumes the associated DataGrid is bound to a DataView or

  // DataTable

  dv := DataView(cm.List);

 

  for i := 0 to dv.Count - 1do

    if (s.Equals(dv[i][cbb.DisplayMember])) then

      break;

 

  if i < dv.Count then

    s := dv[i][cbb.ValueMember]

  else

    s := DBNull.Value;

 

  inherited SetColumnValueAtRow(source, rowNum, s);

end;

 

procedure DataGridComboBoxColumn.DataGrid_Scroll(sender: System.Object; e:
EventArgs);

// On DataGrid scroll, hide the combobox

begin

  cbb.Hide;

end;

 

end.

Und so spreche ich die ComboBox an

...
DGStyle : DataGridTableStyle;
ComboBoxCol1 : DataGridComboBoxColumn;


begin
  //DataGridStyle erzeugen
  DGStyle := System.Windows.Forms.DataGridTableStyle.Create;
  DGStyle.MappingName := FDbPKMView.Table.TableName;
  DGStyle.RowHeaderWidth  := 25;

  //Style Farbe
  DGStyle.AlternatingBackColor := System.Drawing.Color.LightSteelBlue;
  //DGStyle.SelectionBackColor := Color.DarkOrange;



ComboBoxCol1 := DataGridComboBoxColumn.Create;
  SetLookupBinding(ComboBoxCol1.Combobx, 'KFZ_NAME', 'KFZ_ID', FDbKFZView);
  ComboBoxCol1.HeaderText := 'KFZ';

  ComboBoxCol1.Alignment := horizontalalignment.Left;

  ComboBoxCol1.NullText := '';

  ComboBoxCol1.Width := 150;




  //Zum Style hinzufügen
  DGStyle.GridColumnStyles.Clear;
  DGStyle.PreferredRowHeight := ComboBoxCol1.Combobx.Height + 1;
  

  DGStyle.GridColumnStyles.Add(ComboBoxCol1);



  //Ausfuehrung im Datagrid anzeigen
  DataGrid1.TableStyles.Clear;
  DataGrid1.DataSource := FDbPKMView;
  DataGrid1.TableStyles.Add(DGStyle);

Und dann noch die Schleife

procedure SetLookupBinding(combobx: System.Windows.Forms.Combobox; DisplayColumn, BoundColumn: string; dv: DataView);
begin
  with combobx do
  begin
    DisplayMember := DisplayColumn;


end;     ValueMember := BoundColumn;

    DataSource := dv;
  end;

Nur er zeigt mir nix im DataGrid an.

Weiß jemand Rat?