Opening a file by dragging it onto program?

I am writing a program and I am having trouble putting together the necessary code to be able to drag a file onto the program and having it open up and already be displayed like you can do with a JPEG in photoshop.  

If I drag a file onto the program right now it will open the program but it will not actually open the file.  The way the program is designed is there is a blank form with a tree view ontop of it that I use to open specific files and they get displayed on the open form.  What I need to know is how to tell the program what to do with the file I drop onto it or basically how to get the program to open the file automatically after dropping it onto the program.  Thank you for your time.
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Mohammed NasmanSoftware DeveloperCommented:

  Handle the WM_DropFiles message, here's a quick example

TForm1 = class(TForm)
    procedure WMDropFiles(var Msg: TWmDropFiles); message WM_DropFiles;

  Form1: TForm1;


{$R *.dfm}
  ShellAPI, Jpeg;

procedure TForm1.WMDropFiles(var Msg: TWmDropFiles);
  Img: string;
  Img := PChar(Img);
  if UpperCase(ExtractFileExt(Img)) = '.JPG' then

procedure TForm1.FormCreate(Sender: TObject);
  DragAcceptFiles(Handle, True);


Best regards
Mohammed Nasman

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NiZZoBaLLAuthor Commented:
Thank you very much.  That code was exactly what I needed to help me understand it clearly.
Mohammed NasmanSoftware DeveloperCommented:
You are welcome :-)
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