Bad word filter

[blindlizard]

Does anyone know how to make a bad word filter that is case insinsitive? I have been google-ing all night and found some different examples of word filters (some better than others), but none that are case insensitive without changing the case of the text. I basically want to do what this forum does without having to add diferent cases to the words. Like lets say crap is a bad word, I want it to find Crap, crAP, CRAP, etc, but not crape. I know it can be done with regular expressions (which I think this board uses) but I don't know regular expressions worth crap. Here is the code I have now, but it is case sensative:

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim xmlDocPath As String = Server.MapPath("bad_words.xml")
        Dim xmlReader As XmlTextReader = New XmlTextReader(xmlDocPath)
        While (xmlReader.Read())
            If xmlReader.NodeType = XmlNodeType.Text Then
                alWordList.Add(xmlReader.Value)
                Trace.Write("Added: " & xmlReader.Value)
            End If
        End While
        xmlReader.Close()
    End Sub
 
    Public Function CheckString(ByVal InputString As String) As String
        Dim r As Regex
        Dim element As String
        Dim output As String
        Trace.Write("Checking " & InputString)
        For Each element In alWordList
            r = New Regex("\b" & element)
            Trace.Write("Checking: " & element)
            InputString = r.Replace(InputString, "****")
        Next
        Trace.Write("Returning " & InputString)
        Return InputString
    End Function
 
 
XML
<words>
    <word>badword</word>
    <word>reallybadword</word>
    <word>omgyouusedthisword</word>
</words>

[Graff]

Easiest way I can think of is to take the input string put it in a temp string, lower/upper case it all and then compare it against your filter that is also lower/upper cased. Then apply the filter to your input string.

This doesn't take care of your partial matches but it does your case sensativity.

[blindlizard]

Yeah, that is really all I am finding. I was just hoping someone had a regular expreassion filter like this message board. I am building a website for my 7 year old to review video games, and I want pople to be able to leave comments, but what they write is important to audit. I may just have to review everything until I can find/build a robust filter.

[Graff]

http://www.sitepoint.com/forums/show...oto=nextoldest

Maybe this will point you in the right direction

[hellswraith]

// Load up an array of bad words from some ficticious method that returns them.
string[] badWords = GetBadWordList();

string[] myWords = TheText.Split(" ");
bool badWordInString = false;

foreach(string word in myWords)
{
  foreach(string badword in badWords)
  {
     if(word.ToUpper() == badWord.ToUpper())
     {
        badWordInString = true;
        break;
     }
  }
}

if(badWordInString)
   //Do Something....

[blindlizard]

That looks pretty good hellswraith, and if I find a bad word, then I can update that element of the array, and then make a new string

foreach(string word in myWords)
{
  foreach(string badword in badWords)
  {
     if(word.ToUpper() == badWord.ToUpper())
     {
        word = '***';
     }
  }
}

string myNewString = '';
foreach(string word in myWords)
{
   myNewString = myNewString + word;
}