請教各位前輩    如何寫 Edit + DBGRID 功能的VCL ?    目前想寫一個Edit + DBGRID 功能的VCL 有點像 TComboBox,但要自己加一些東西 但不知為何,無法顯示出DBGRID?? 可否請各位前輩指導??    萬分感謝.....謝謝.....謝謝    --------     

unit EditDBGRID;    interface    uses
  SysUtils, Classes, Controls, StdCtrls,DBGrids ;    type
  TEditDBGRID = class(TEdit)
  private
    { Private declarations }
        DBGrid1: TDBGrid;      protected
    { Protected declarations }
  public
    { Public declarations }
    constructor Create(Aowner:TComponent);override;
       destructor Destroy;override;
  published
    { Published declarations }
  end;    procedure Register;    implementation
constructor TEditDBGRID.Create(AOwner:TComponent);
begin
  inherited Create(Aowner);
  {Initialize Button}
  DBGrid1:= TDBGrid.Create(self.Parent);
   DBGrid1.Top :=0   ;
   DBGrid1.Left :=0   ;
   DBGrid1.Height:=100;
    DBGrid1.Width:=100;
   DBGrid1.Parent :=self.Parent ;
      DBGrid1.Show;
      DBGrid1.Visible:=True;
//
end;    destructor TEditDBGRID.Destroy;
begin      inherited Destroy;
  //
end;
procedure Register;
begin
  RegisterComponents('Test', [TEditDBGRID]);
end;    end.     

臨時寫的，若不完善及Bug 請自行處理一下。 粉累！事實上這類元件，網站上搜一下是蠻多的。 不過自己寫樂趣多彈性大，也能加深對 VCL 的認識。    

unit EveditGrid;    interface    uses
  Sysutils,Classes,StdCtrls,Messages,Controls,Forms,Windows,Graphics
  ,Grids,DBGrids;    Type
  TEvEditGrid = Class;
  TEvDown = class(TGraphicControl)
  private
    FPressed : Boolean;
    fEditCtrl : TEvEditGrid;
  protected
    procedure MouseDown(Button: TMouseButton; Shift: TShiftState;X, Y: Integer); Override;
    procedure MouseUp(Button: TMouseButton; Shift: TShiftState;X, Y: Integer);Override;
    procedure Paint; Override;
  public
    constructor Create(AOwner: TComponent); override;
    property EditCtrl:TEvEditGrid read fEditCtrl write fEditCtrl;
  published
  end;      TEvEditGrid = class(TEdit)
  private
    FButton : TEvDown;
    fDBGrid :TDBGrid;        procedure SetEditRect;
    procedure WMSize(var Message: TWMSize); message WM_SIZE;
    procedure CMCancelMode(var Message: TCMCancelMode); message CM_CancelMode;
  protected
    procedure Loaded; override;
    procedure KeyPress(var Key: Char);override;
    procedure CreateWnd;override;
    procedure CreateParams(var Params: TCreateParams);Override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
  published
    Property DBGrid :TDBGrid read fDBGrid write fDBGrid;        Property Ctl3D;
    property BorderStyle;
    Property Align;
  end;
  procedure Register;    implementation    procedure Register;
begin
  RegisterComponents('Samples',[TEvEditGrid]);
end;    constructor TEvDown.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Width := GetSystemMetrics(SM_CXVSCROLL);
  Height := 10;
  ControlStyle := ControlStyle - [csDoubleClicks];
end;    procedure TEvDown.MouseDown(Button: TMouseButton; Shift: TShiftState;X, Y: Integer);
Const
  GridVisibleRowCount = 5;
var
  GridHeight:Integer;
  PS : TPoint;
begin
  inherited MouseDown(Button, Shift, X, Y);
  if (Button = mbLeft) then
  begin
    if not fEditCtrl.DBGrid.Visible then
    begin
      FPressed := True;
      With fEditCtrl do
      begin
        GridHeight := TStringGrid(DBGrid).RowHeights[0]
                     (TStringGrid(DBGrid).DefaultRowHeight*5)   4;
        PS := TForm(Owner).ClientToScreen(Point(Left,Top   Height));            DBGrid.SetBounds(PS.x,PS.y,Width,GridHeight);
        DBGrid.Visible := True;
        SetWindowPos(DBGrid.Handle,HWND_TOP,0,0, 0, 0
                    ,SWP_NOMOVE or SWP_NOSIZE or SWP_NOACTIVATE or SWP_SHOWWINDOW);
      end;
      Repaint;
    end else fEditCtrl.DBGrid.Visible := False;
  end;
end;    procedure TEvDown.MouseUp(Button: TMouseButton; Shift: TShiftState;X, Y: Integer);
begin
  inherited MouseUp(Button, Shift, X, Y);
  if FPressed then
  begin
    FPressed := False;
    Repaint;
  end;
end;    procedure TEvDown.Paint;
var
  Flags : Integer;
  ARect : TRect;
begin
  ARect := Canvas.ClipRect;
  if FPressed then Flags := DFCS_FLAT or DFCS_PUSHED else Flags := 0;
  DrawFrameControl(Canvas.Handle, ARect, DFC_SCROLL, Flags or DFCS_SCROLLCOMBOBOX);
end;    {TEvEditGrid}
constructor TEvEditGrid.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  FDBGrid := TDBGrid.Create(Self);
  FDBGrid.Parent := Self;
  FDBGrid.Visible := False;
  FButton := TEvDown.Create(Self);
  FButton.Parent   := Self;
  FButton.EditCtrl := Self;
  FButton.Cursor := crArrow;
end;    destructor TEvEditGrid.Destroy;
begin
  FButton.Free;
  FDBGrid.Free;
  inherited Destroy;
end;    procedure TEvEditGrid.Loaded;
begin
  inherited;
  Windows.SetParent(FDBGrid.Handle, 0);
end;    procedure TEvEditGrid.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params);
  Params.Style := Params.Style or ES_MULTILINE;
end;    procedure TEvEditGrid.SetEditRect;
var
  BRect : TRect;
begin
  BRect := Rect(0,0,ClientWidth - FButton.Width - 1
                   ,ClientHeight   1 );
  SendMessage(Handle, EM_SETRECT, 0, LongInt(@ BRect));
end;    procedure TEvEditGrid.CreateWnd;
begin
  inherited CreateWnd;
  SetEditRect;
end;    procedure TEvEditGrid.WMSize(var Message: TWMSize);
begin
  inherited;
  FButton.SetBounds(ClientWidth-FButton.Width,0,FButton.Width,ClientHeight);
  SetEditRect;
end;    procedure TEvEditGrid.KeyPress(var Key: Char);
begin
  inherited KeyPress(Key);
  if Key=#13 then
  begin
    Key := #0;
    MessageBeep(0)
  end;
end;    procedure TEvEditGrid.CMCancelMode(var Message: TCMCancelMode);
begin
  inherited;
  fDBGrid.Visible := False;
end;    end.

若不瞭解之處，請跟我說。 ～～～～～～～～～～～ 難得聰明，常常糊塗。 ～～～～～～～～～～～ 發表人 - wameng 於 2005/05/21 22:33:38

to jeffreck:    1.Owner與Parent功能不同,搜尋一下站上主題,應能找到不少資料.你的做法在Create的地方有錯誤,DBGrid1要能顯示,並不應該在Create時就顯示,而是在設定TEditDBGrid.Parent時才顯示,所以,你應該override SetParent這個procedure(宣告在Protected裡),當然,create裡就不需要去設定DBGrid的Parent,Show,visible等(我想你應該是在試如何讓物件顯示才加的吧),如下

procedure TEditDBGRID.SetParent(AParent: TWinControl);
begin
  DBGrid1.Parent:=AParent;
  inherited;
end;

2.新的物件,建議從TCustomerEdit繼承下來會比直接從TEdit繼承下來要好. 3.如果有source code的話,可以參考TLabeledEdit的做法,應該可以得到不少的東西