Is there a bug in System.Web.HttpUtility.UrlDecode?

Question

Consider the following line of code:

string _decoded = System.Web.HttpUtility.UrlDecode(
  "There%20should%20be%20text%20after%20this%0022help!");

The encoded line

"There%20should%20be%20text%20after%20this%0022help!" 

when decoded via the website urldecoder.org produces

"There should be text after this22help!"

however the value of _decoded as displayed in the debugger is: Figure 1: Debugger view of problem

What could be causing this problem? Is there a setting or special encoding that will circumvent this in all cases?

EDIT: Yes, I consider this behavior to be an error. I don't want URLDecode to introduce the \0 char to the resultant string, because it would result in an invalid file name (my code is moving around files).

Answer 1

There is a null byte (\0 = %00) after this so the debugger doesn't show the rest of the string.

So the decoded value is correct, it's just the limitation (or bug?) of the debugger.

You can take a look at here for more info about null byte from security perspective. And there is this question posted about it as well.