Delphi XE8 Load PDF File

Question

I want to know how to do either:

1. On a button click, open a PDF file from a directory.

2. View a PDF file on the Form.

Answer 1

You don't need all of the jumping-through hoops you're doing. Windows will find the application associated with PDF files for you.

procedure TForm1.Button1Click(Sender: TObject);
var
  s: String;     
  Ret: DWord;
begin
  s := 'C:\MyFiles\MyFile.pdf';
  Ret := ShellExecute(Handle, nil, PChar(s), nil, nil, SW_SHOW);
  if Ret < 32 then
    ShowMessage(SysErrorMessage(GetLastError));
end;

Note: Normally you should never call a WinAPI function without checking the return value. In this case, you'll know if it didn't work because the PDF won't open.