Removing duplicate substrings within a string in C#
<p>How can I remove duplicate substrings within a string?  so for instance if I have a string like <code>smith:rodgers:someone:smith:white</code> then how can I get a new string that has the extra <code>smith</code> removed like <code>smith:rodgers:someone:white</code>. Also I'd like to keep the colons even though they are duplicated.</p>

<p>many thanks</p>
