You could easily accomplish this by custom drawing and using a state
object stored in each items object property.
OK, I took a few minutes to create an example. Create a new project,
save the form as MAIN.pas and then drop a Tcombobox on it. Generate
event stubs for FormCreate, FormDestroy and ComboBox1DrawItem.
Copy the following unit over the existing main.pas source.
While this works fine for the one off chance, I'd recommend creating a
TComboBox descendant that has a DisableItems TStrings published
property. This would then eliminate the need to utilise the Objects
property for each entry in the combobox.
///////// unit code
unit Main;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TStateObject = class
private
FEnabled: Boolean;
public
constructor Create(const AEnabled: Boolean);
property Enabled: Boolean read FEnabled;
end;
TForm29 = class(TForm)
ComboBox1: TComboBox;
procedure FormCreate(Sender: TObject);
procedure ComboBox1DrawItem(Control: TWinControl; Index: Integer;
Rect: TRect; State: TOwnerDrawState);
procedure FormDestroy(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form29: TForm29;
implementation
{$R *.dfm}
{ TStateObject }
constructor TStateObject.Create(const AEnabled: Boolean);
begin
FEnabled := AEnabled;
end;
procedure TForm29.ComboBox1DrawItem(Control: TWinControl; Index: Integer;
Rect: TRect; State: TOwnerDrawState);
var
lObj: TStateObject;
lCombo: TComboBox;
lDrawFlags: Cardinal;
lStr: string;
begin
if not (Control is TComboBox) then
exit;
lCombo := (Control as TComboBox);
lObj := TStateObject(lCombo.Items.Objects[Index]);
lCombo.Canvas.Brush.Style := bsSolid;
// setup background color
if (odSelected in State) and lObj.Enabled then
lCombo.Canvas.Brush.Color := clHighlight
else
lCombo.Canvas.Brush.Color := lCombo.Color;
lCombo.Canvas.FillRect(Rect);
lCombo.Canvas.Brush.Style := bsClear;
// setup font color
if (odSelected in State) and lObj.Enabled then
lCombo.Canvas.Font.Color := clHighlightText
else if not lObj.Enabled then
lCombo.Canvas.Font.Color := clGrayText
else
lCombo.Canvas.Font.Color := Font.Color;
InflateRect(Rect, -2, -2);
lDrawFlags := DT_LEFT or DT_VCENTER or DT_SINGLELINE or DT_NOPREFIX
or DT_END_ELLIPSIS;
lStr := lCombo.Items[Index];
DrawText(lCombo.Canvas.Handle, PChar(lStr), Length(lStr), Rect, lDrawFlags);
// comment this out if you want the focus rect to be draw even when a
// disabled item has focus
if (odSelected in State) and not lObj.Enabled then
begin
InflateRect(Rect, 2, 2);
DrawFocusRect(lCombo.Canvas.Handle, Rect);
end;
end;
procedure TForm29.FormCreate(Sender: TObject);
begin
ReportMemoryLeaksOnShutdown := True;
ComboBox1.Style := csOwnerDrawFixed;
ComboBox1.Items.AddObject('One', TStateObject.Create(True));
ComboBox1.Items.AddObject('Two', TStateObject.Create(True));
ComboBox1.Items.AddObject('Three', TStateObject.Create(False));
ComboBox1.Items.AddObject('Four', TStateObject.Create(False));
ComboBox1.Items.AddObject('Five', TStateObject.Create(True));
end;
procedure TForm29.FormDestroy(Sender: TObject);
var
i: Integer;
begin
for i := 0 to ComboBox1.Items.Count - 1 do
TStateObject(ComboBox1.Items.Objects[i]).Free;
end;
end.
///////// end of unit code
Hope this helps,
Jeremy
On Dec 2, 2007 2:09 AM, John Barrat <[EMAIL PROTECTED]> wrote:
> Is it possible to enable individual items in the list of items.
> I want to show a complete list of items but only show specific items as
> being enabled and therefore selectable.
> I am sure I have done this before but damned if I can remember how.
>
> JohnB
> _______________________________________________
> Delphi mailing list -> [email protected]
> http://lists.elists.org/cgi-bin/mailman/listinfo/delphi
>
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