{"id":97,"date":"2007-05-12T13:58:13","date_gmt":"2007-05-12T11:58:13","guid":{"rendered":" http:\/\/www.nsonic.de\/blog\/2007\/05\/adding-a-combobox-to-a-cell\/"},"modified":"2007-05-12T13:58:15","modified_gmt":"2007-05-12T11:58:15","slug":"adding-a-combobox-to-a-cell","status":"publish","type":"post","link":"https:\/\/www.nsonic.de\/blog\/2007\/05\/adding-a-combobox-to-a-cell\/","title":{"rendered":"Adding a ComboBox to a cell"},"content":{"rendered":"

> I am using Delphi 2.0. I have a TStringGrid. In one of the columns, I want
\n> the cells to act as ComboBoxes; i.e. each of the cells in that column would
\n> have a small down arrow button which, when clicked, would show a
\n> drop-down list from which the user could choose an item for the cell.
\n>
\n> Any ideas on how I would go about this? Thanks.
\n>
\n<\/em>
\nthere are several approaches here. A very simple one would just display a
\ngenuine combobox on top of the cell when the user clicks on the cell. If you
\nwant to see an arrow button in the cell in this scenario you would have to
\ndraw it yourself in an OnDrawCell event.
\n
\nAttach a combobox to a stringgrid column<\/p>\n

[code lang=”delphi”]unit Unit1;<\/p>\n

interface<\/p>\n

uses
\n Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
\n StdCtrls, Grids;<\/p>\n

type
\n TForm1 = class(TForm)
\n StringGrid1: TStringGrid;
\n ComboBox1: TComboBox;
\n procedure ComboBox1Exit(Sender: TObject);
\n procedure FormCreate(Sender: TObject);
\n procedure StringGrid1SelectCell(Sender: TObject; ACol, ARow: Integer;
\n var CanSelect: Boolean);
\n private
\n { Private declarations }
\n Procedure CMDialogKey( Var msg: TCMDialogKey );
\n message CM_DIALOGKEY;
\n public
\n { Public declarations }
\n end;<\/p>\n

var
\n Form1: TForm1;<\/p>\n

implementation<\/p>\n

{$R *.DFM}<\/p>\n

procedure TForm1.CMDialogKey(var msg: TCMDialogKey);
\nbegin
\n If Activecontrol = Combobox1 Then Begin
\n If msg.CharCode = VK_TAB Then Begin
\n \/\/ set focus back to the grid and pass the tab key to it
\n stringgrid1.setfocus;
\n stringgrid1.perform( WM_KEYDOWN, msg.charcode, msg.keydata );
\n \/\/ swallow this message
\n msg.result := 1;
\n Exit;
\n End;
\n End;
\n inherited;
\nend;<\/p>\n

procedure TForm1.ComboBox1Exit(Sender: TObject);
\nbegin
\n with sender as TCombobox do begin
\n hide;
\n if itemindex >= 0 then
\n with stringgrid1 do
\n cells[ col, row ] := items[itemindex];
\n end;
\nend;<\/p>\n

procedure TForm1.FormCreate(Sender: TObject);
\nbegin
\n combobox1.visible := false;
\nend;<\/p>\n

procedure TForm1.StringGrid1SelectCell(Sender: TObject; ACol,
\n ARow: Integer; var CanSelect: Boolean);
\nvar
\n R: TRect;
\n org: TPoint;
\nbegin
\n With Sender As TStringgrid Do
\n If (ACol = 2) and (ARow >= FixedRows) Then Begin
\n \/\/ entered the column associated to the combobox
\n \/\/ get grid out of selection mode
\n perform( WM_CANCELMODE, 0, 0 );
\n \/\/ position the control on top of the cell
\n R := CellRect( Acol, Arow );
\n org:= Self.ScreenToClient( ClientToScreen( R.topleft ));
\n With combobox1 do begin
\n setbounds( org.X, org.Y, r.right-r.left, height );
\n itemindex := Items.IndexOf( Cells[ acol, arow ] );
\n Show;
\n BringTofront;
\n \/\/ focus the combobox and drop down the list
\n SetFocus;
\n DroppedDown := true;
\n end;
\n End;
\nend;<\/p>\n

end.
\n[\/code]
\nWith a little modification the TStringgrid class can also be made to actually
\nparent a combonent. You need to modify the way it handles WM_COMMAND for this:<\/p>\n

[code lang=”delphi”]unit ControlStringgrid;<\/p>\n

interface<\/p>\n

uses
\n Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
\n Grids;<\/p>\n

type
\n TControlStringgrid = class(TStringgrid)
\n private
\n { Private declarations }
\n Procedure WMCommand( var msg: TWMCommand ); message WM_COMMAND;
\n protected
\n { Protected declarations }
\n public
\n { Public declarations }
\n published
\n { Published declarations }
\n end;<\/p>\n

procedure Register;<\/p>\n

implementation<\/p>\n

procedure Register;
\nbegin
\n RegisterComponents(‘PBGoodies’, [TControlStringgrid]);
\nend;<\/p>\n

{ TControlStringgrid }<\/p>\n

procedure TControlStringgrid.WMCommand(var msg: TWMCommand);
\nbegin
\n If EditorMode and ( msg.Ctl = InplaceEditor.Handle ) Then
\n inherited
\n Else
\n If msg.Ctl <> 0 Then
\n msg.result :=
\n SendMessage( msg.ctl, CN_COMMAND,
\n TMessage(msg).wparam,
\n TMessage(msg).lparam );
\nend;<\/p>\n

end.
\n[\/code]
\nUsing this grid you can create a combobox as child of the grid, which has the
\nadvantage that it will scroll with the grid while visible.<\/p>\n

Peter Below (TeamB)<\/p>\n

[tags]Delphi, Components, StringGrid[\/tags]<\/p>\n","protected":false},"excerpt":{"rendered":"

> I am using Delphi 2.0. I have a TStringGrid. In one of the columns, I want > the cells to act as…<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":""},"categories":[11],"tags":[90,75,94],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p71Tml-1z","_links":{"self":[{"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/posts\/97"}],"collection":[{"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/comments?post=97"}],"version-history":[{"count":0,"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/posts\/97\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/media?parent=97"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/categories?post=97"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/tags?post=97"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}