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Question about a color rows in my own listview component

Dear Experts,

I have this to color the rows of a listview:

procedure TMainForm.PkListv1CustomDrawItem(Sender: TCustomListView;
Item: TListItem; State: TCustomDrawState; var DefaultDraw: Boolean);
begin
if Odd(Item.Index) then
PkListv1.Canvas.Brush.Color := clGray
else
PkListv1.Canvas.Brush.Color := clWindow;
end;

I am making my own listview-component, can this code above
be build in the component itself, i guess i have to use the onpaint
event, but I have no clue how to start. Does someone has the
experience with that?

Greetings, Peter

unit PkListView;

interface

uses
  SysUtils, Classes, Controls, ComCtrls, Windows;

type
  PkListv = class(TListView)
  private
    { Private declarations }
  protected
    { Protected declarations }
   FHeaderHandle: HWND;
   function GetHeaderHeight:Integer;
   procedure SetHeaderHeight(h:Integer);
  public
    { Public declarations }
    constructor Create(AOwner: TComponent);
    destructor Destroy();
  published
    { Published declarations }
   property HeaderHeight:Integer read GetHeaderHeight write SetHeaderHeight;
  end;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('Samples', [PkListv]);
end;

{ PkListv }

const
  LVM_FIRST = $1000;
  LVM_GETHEADER = LVM_FIRST + 31;

constructor PkListv.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);

end;

destructor PkListv.Destroy;
begin
  inherited;
end;

function PkListv.GetHeaderHeight: Integer;
Var
  Rc:TRect;
begin
 Result:=0;
 FHeaderHandle:=SendMessage(Handle, LVM_GETHEADER, 0, 0);
 If GetWindowRect(FHeaderHandle, rc)
  Then Result := rc.Bottom - rc.Top
end;

procedure PkListv.SetHeaderHeight(h: Integer);
begin
 FHeaderHandle:=SendMessage(Handle, LVM_GETHEADER, 0, 0);
 SetWindowPos( FHeaderHandle, 0 , 0, 0, Width, h, 0 );
 InvalidateRect(FHeaderHandle,nil,True);
end;

end.

Open in new window

Emmanuel PASQUIER

you'll have to override TCustomListView.CustomDrawItem method that is calling this event, see Delphi code below :

function TCustomListView.CustomDrawItem(Item: TListItem; State: TCustomDrawState;
Stage: TCustomDrawStage): Boolean;
begin
Result := True;
if (Stage = cdPrePaint) and Assigned(FOnCustomDrawItem) then FOnCustomDrawItem(Self, Item, State, Result);
if Assigned(FOnAdvancedCustomDrawItem) then FOnAdvancedCustomDrawItem(Self, Item, State, Stage, Result);
end;

  PkListv = class(TListView)
  private
    { Private declarations }
  protected
    { Protected declarations }
   FHeaderHandle: HWND;
   function GetHeaderHeight:Integer;
   procedure SetHeaderHeight(h:Integer);
   function CustomDrawItem(Item: TListItem; State: TCustomDrawState;
      Stage: TCustomDrawStage): Boolean; override;
  public
    { Public declarations }
    constructor Create(AOwner: TComponent);
    destructor Destroy();
  published
    { Published declarations }
   property HeaderHeight:Integer read GetHeaderHeight write SetHeaderHeight;
  end;

implementation
...

function PkListv.CustomDrawItem(Item: TListItem; State: TCustomDrawState;
  Stage: TCustomDrawStage): Boolean;
begin
 if Odd(Item.Index) 
  then Canvas.Brush.Color := clGray
  else Canvas.Brush.Color := clWindow;
 Result:= inherited CustomDrawItem(Item,State,Stage);
end;

Open in new window

Peter Kiers

ASKER

How do you do that?

How do you know that the customdrawitem has to be changed?

Peter

Peter Kiers

ASKER

In order to test your code I have to put data in the rows of the listview:
How can I fill a line of text dynamicly?

procedure TMainForm.btnTESTClick(Sender: TObject);
var
MyListv: PkListv;
MyListCol : TListColumn;
begin
MyListv:= PkListv.Create(Self);
MyListv.Parent := self;
MyListv.Align := alTop;
MyListv.Height := 300;
MyListv.ViewStyle := vsReport;
MyListv.GridLines := True;
MyListv.ColumnClick := False;
MyListv.SmallImages := ImageList1;
MyListv.HeaderHeight:=20;
MyListv.Items <==================================
MyListCol := MyListv.Columns.Add;
MyListCol.Alignment := taLeftJustify;
MyListCol.Width := 150;
MyListCol.Caption := 'Naam';
end;

ASKER CERTIFIED SOLUTION

Emmanuel PASQUIER

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Peter Kiers

ASKER

Thanks it works.

Peter