hi

i'm trying to load an image into the TCanvasImage object, but seem to be having difficulty with this

when I run the page and press 'button1' (example below) to load the image at runtime.. I get an application error :

"unable to get property 'tcanvasimage_setname' of undefined or null reference"

I do have a 'hello.png' in the same location as the loader file

somehow i'm misunderstanding how to use the 'name' property of the TCanvasImage,
or maybe i'm misunderstanding something about the object creation

thanks, still fairly new at EWB (v1.03, build 4)

.. Bruno

///////////////////////////////////////////////// EXAMPLE BELOW ///////////////////////////////////////

unit Unit1;

interface

uses WebCore, WebForms, WebCtrls;

type

  TForm1 = class(TForm)
     Paint1: TPaint;
     Button1: TButton;
     Button2: TButton;
     procedure Button1Click(Sender: TObject);
     procedure Button2Click(Sender: TObject);
  private
     { Private declarations }
  public
     { Public declarations }
     canvasImage1: TCanvasImage;
  end;

var
  Form1: TForm1;

implementation

procedure TForm1.Button1Click(Sender: TObject);
begin

canvasImage1.name := 'hello.png'; //this is in the 'output' folder

end;



procedure TForm1.Button2Click(Sender: TObject);
begin

if canvasImage1.loaded = true then
begin
paint1.canvas.drawImage(canvasImage1,0,0);
end
else
begin
showMessage('it is not loaded yet!');
end;

end;

end.

/////////////////////////////////////////////////////////////////////////////////////////

ok, I decided to use my brain, I was forgetting to create the object dynamically

duh!

procedure TForm1.Button1Click(Sender: TObject);
begin

canvasImage1 := TCanvasImage.create();

canvasImage1.name := 'hello.png'; //this is in the 'output' folder
end;

////////// resolved! /////////////








Bruno Larochelle wrote:

hi

i'm trying to load an image into the TCanvasImage object, but seem to be having difficulty with this

when I run the page and press 'button1' (example below) to load the image at runtime.. I get an application error :

"unable to get property 'tcanvasimage_setname' of undefined or null reference"

I do have a 'hello.png' in the same location as the loader file

somehow i'm misunderstanding how to use the 'name' property of the TCanvasImage,
or maybe i'm misunderstanding something about the object creation

thanks, still fairly new at EWB (v1.03, build 4)

.. Bruno

///////////////////////////////////////////////// EXAMPLE BELOW ///////////////////////////////////////

unit Unit1;

interface

uses WebCore, WebForms, WebCtrls;

type

  TForm1 = class(TForm)
     Paint1: TPaint;
     Button1: TButton;
     Button2: TButton;
     procedure Button1Click(Sender: TObject);
     procedure Button2Click(Sender: TObject);
  private
     { Private declarations }
  public
     { Public declarations }
     canvasImage1: TCanvasImage;
  end;

var
  Form1: TForm1;

implementation

procedure TForm1.Button1Click(Sender: TObject);
begin

canvasImage1.name := 'hello.png'; //this is in the 'output' folder

end;



procedure TForm1.Button2Click(Sender: TObject);
begin

if canvasImage1.loaded = true then
begin
paint1.canvas.drawImage(canvasImage1,0,0);
end
else
begin
showMessage('it is not loaded yet!');
end;

end;

end.

/////////////////////////////////////////////////////////////////////////////////////////

Bruno Larochelle wrote:

> "unable to get property 'tcanvasimage_setname' of undefined or null
> reference

As you found, the clue is in the "undefined or null reference" part.
Pretty much always means you didn't assign a value to an object
variable.

--

Matthew Jones