An example of how we can filter certain words in a string and mask them by replacing them with an asterisk.

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load  
        ' Declarations  
        Dim arrWords As New ArrayList  
        Dim strArticle As String = "This is one sample string that three people wrote"  
      
        ' Populate the array list with the words we want to replace  
        arrWords.Add("one")  
        arrWords.Add("two")  
        arrWords.Add("three")  
     
       ' Loop through the array list and replace each found word with *'s  
       Dim IEnum As IEnumerator = arrWords.GetEnumerator  
       While IEnum.MoveNext  
           strArticle = strArticle.ToLower.Replace(IEnum.Current, New String("*", IEnum.Current.ToString.Length))  
       End While  
     
       ' Show the resulting string  
       Label1.Text = strArticle  
   End Sub