Delphi Drawers

function fnGetDragFilePath(var strFile:string):integer;
var
  strPath:string;
  iRes:integer;
begin
  strFile := '';
  case paramcount of
    0:iRes := -2;
    1:iRes := 1;
    else iRes := -3;
  end;
  if iRes = 1 then begin
    strPath := ParamStr(1);
    if FileExists(strPath) then begin
      strFile := ParamStr(1);
    end else begin
      iRes := -4;
    end;
  end;
  Result := iRes;
end;