ASP.NET / VB / REGEX: Test for match instead of replace

The code below replaces matches inside a string.  Instead of replacing all matches inside the string, I want the entire string to be replaced if there is a match.

The string should become empty if there is no match and it should contain the full word if there is a match.

Please test this:

<%@ Page Language="VB" AutoEventWireup="false" %>
<% 
Dim str As String

str = "in is a state in America near Michigin"
str = RegularExpressions.Regex.Replace(str, "(?i)\bin\b", "Indiana")
Response.Write(str)
' Should return "Indiana"

Response.Write("<hr />")

str = "Testing 123"
str = RegularExpressions.Regex.Replace(str, "(?i)\bin\b", "Indiana")
Response.Write(str)
' Should not return anything

%>

Select allOpen in new window