Disable a single row in a listbox

Would it not be better to use the standard Dual Listbox form idea?
Instead of just copying the item to the second listbox and disabling the first, move it to the second listbox.
This would be a much better way of handling it.

If you REALLY want to be able to move it back to its previous location in the first list, you might be better loading all the items to go into the first listbox into an objectlist, with each object holding its position and visible text.
This way you always know where to put the item back if you decide not to include it in the second list, and can just pass the objects from one list to the other.

Just my 2 cents.

This is from a post by Jacco. It was origianlly for a ComboBox but I modified it to work with
a ListBox:

procedure SetDisabledItem(AListBox: TListBox; AIndex: Integer; AValue: Boolean);
begin
  if not Assigned(AListBox) then
    Exit;
  if AIndex < AListBox.Items.Count then
  begin
    if AValue then
    begin
      if Integer(AListBox.Items.Objects[AIndex]) = 0 then
      begin
        if AIndex = AListBox.ItemIndex then
          AListBox.Tag := -1;
        AListBox.Items.Objects[AIndex] := Pointer(1);
        AListBox.Items[AIndex] := '['+AListBox.Items[AIndex]+']';
      end;
    end
    else
    begin
      if Integer(AListBox.Items.Objects[AIndex]) <> 0 then
      begin
        AListBox.Items.Objects[AIndex] := nil;
        AListBox.Items[AIndex] := Copy(AListBox.Items[AIndex], 2, Length(AListBox.Items[AIndex])-2);
      end;
    end;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  SetDisabledItem(ListBox1,1,True);
end;


procedure TForm1.Button2Click(Sender: TObject);
begin
  SetDisabledItem(ListBox1,1,False);
end;

procedure TForm1.ListBox1Click(Sender: TObject);
begin
  with TListBox(Sender) do
  begin
    if Integer(Items.Objects[ItemIndex]) <> 0 then
    begin
      ItemIndex := Tag;
    end
    else
    begin
      Tag := ItemIndex;
    end;
  end;
end;

Set the Style to lbOwnerDrawnFixed and this code will make it draw in a different color:

procedure SetDisabledItem(AListBox: TListBox; AIndex: Integer; AValue: Boolean);
begin
  if not Assigned(AListBox) then
    Exit;
  if AIndex < AListBox.Items.Count then
  begin
    if AValue then
    begin
      if Integer(AListBox.Items.Objects[AIndex]) = 0 then
      begin
        if AIndex = AListBox.ItemIndex then
          AListBox.Tag := -1;
        AListBox.Items.Objects[AIndex] := Pointer(1);
      end;
    end
    else
    begin
      if Integer(AListBox.Items.Objects[AIndex]) <> 0 then
      begin
        AListBox.Items.Objects[AIndex] := nil;
      end;
    end;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  SetDisabledItem(ListBox1,1,True);
  ListBox1.Invalidate;
end;


procedure TForm1.Button2Click(Sender: TObject);
begin
  SetDisabledItem(ListBox1,1,False);
  ListBox1.Invalidate;
end;

procedure TForm1.ListBox1Click(Sender: TObject);
begin
  with TListBox(Sender) do
  begin
    if Integer(Items.Objects[ItemIndex]) <> 0 then
    begin
      ItemIndex := Tag;
    end
    else
    begin
      Tag := ItemIndex;
    end;
  end;
end;

procedure TForm1.ListBox1DrawItem(Control: TWinControl; Index: Integer;
  Rect: TRect; State: TOwnerDrawState);
var
  LB: TListBox;
  ItemText: String;
begin
  LB := TListBox(Control);
  ItemText := LB.Items[Index];
  if odSelected in State then
    LB.Canvas.Brush.Color := clHighLight
  else
    if Integer(LB.Items.Objects[Index]) <> 0 then
    begin
      LB.Canvas.Brush.Color := clInactiveCaption;
      LB.Canvas.Font.Color  := clInactiveCaptionText;
    end
    else
      LB.Canvas.Brush.Color := clWindow;
  LB.Canvas.FillRect(Rect);
  LB.Canvas.TextOut(Rect.Left+2, Rect.Top, LB.Items[Index]);
end;

Hi,

Add a listbox on your form and compile.
unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TForm1 = class(TForm)
    ListBox1: TListBox;
    procedure FormCreate(Sender: TObject);
    procedure ListBox1DrawItem(Control: TWinControl; Index: Integer;
      Rect: TRect; State: TOwnerDrawState);
    procedure ListBox1Click(Sender: TObject);
    procedure ListBox1DblClick(Sender: TObject);
  private
    { Déclarations privées }
  public
    { Déclarations publiques }
  end;

var
  Form1: TForm1;
  i: integer;

  implementation

{$R *.DFM}

procedure TForm1.FormCreate(Sender: TObject);
var
j: integer;
begin
 ListBox1.Style:= lbOwnerDrawFixed;
 for j:=0 to 3 do listbox1.Items.Add('Item ' + inttostr(j));
 for j:=4 to 6 do ListBox1.Items.AddObject('Grayed Item' + inttostr(j), Pointer(clSilver));
 for j:=7 to 10 do   ListBox1.Items.AddObject('Teal Item' + inttostr(j), Pointer(clTeal));
end;

procedure TForm1.ListBox1DrawItem(Control: TWinControl; Index: Integer;
  Rect: TRect; State: TOwnerDrawState);
begin
  with Control as TListBox do
  begin
    Canvas.FillRect(Rect);
    Canvas.Font.Color := TColor(Items.Objects[Index]);
    Canvas.TextOut(Rect.Left + 2, Rect.Top, Items[Index]);
  end;
end;

procedure TForm1.ListBox1Click(Sender: TObject);
begin
if  colortostring(TColor(Listbox1.Items.Objects[ListBox1.itemindex])) = 'clSilver' then Showmessage('Disabled');
end;

procedure TForm1.ListBox1DblClick(Sender: TObject);
begin
i:= Listbox1.itemindex;
ListBox1.Items.InsertObject(i,listbox1.items[Listbox1.itemindex], Pointer(clRed));
ListBox1.Items.Delete(i+1);
end;

end.