How to: Strip Invalid Characters from a String 

The following code example uses the static Regex.Replace method to strip invalid characters from a string. You can use the CleanInput method defined here to strip potentially harmful characters that have been entered into a text field in a form that accepts user input. CleanInput returns a string after stripping out all nonalphanumeric characters except @, - (a dash), and . (a period).

Example

    Function CleanInput(strIn As String) As String
        ' Replace invalid characters with empty strings.
        Return Regex.Replace(strIn, "[^\w\.@-]", "")
    End Function

    String CleanInput(string strIn)
    {
        // Replace invalid characters with empty strings.
        return Regex.Replace(strIn, @"[^\w\.@-]", ""); 
    }

See Also

Other Resources

.NET Framework Regular Expressions