这个PHP代码在VB.net中是什么[关闭]

I am looking for the vb.net equivalent of this function: I have no experience of PHP but came across this code which apparently gives you a random image url from google images

    function GetRandomImageURL($topic='', $min=0, $max=100)
{
  // get random image from Google
  if ($topic=='') $topic='image';
  $ofs=mt_rand($min, $max);
  $geturl='http://www.google.ca/images?q=' . $topic . '&start=' . $ofs . '&gbv=1';
  $data=file_get_contents($geturl);

  $f1='<div id="center_col">';
  $f2='<a href="/imgres?imgurl=';
  $f3='&amp;imgrefurl=';

  $pos1=strpos($data, $f1)+strlen($f1);
  if ($pos1==FALSE) return FALSE;
  $pos2=strpos($data, $f2, $pos1)+strlen($f2);
  if ($pos2==FALSE) return FALSE;
  $pos3=strpos($data, $f3, $pos2);
  if ($pos3==FALSE) return FALSE;
  return substr($data, $pos2, $pos3-$pos2);
}

Its mostly string manipulation, building up the image url. It picks a pseudo random image between index 0 and 100 on this line

$ofs=mt_rand($min, $max);

The same can be achieved with the Random class in .Net

Dim rnd As New Random()
Dim ofs As Int = rnd.Next(min, max)

I leave the string manipulation to the OP but its probably better to do it with the StringBuilder class, or perhaps one String.Format.

It worth considering if the 0 to 100 bounds are overly abritary.