IIS Rewrite Rule double question marks

Question

I'm trying to create a rewrite rule that will remove a username from the URL and instead append a userID to the URL. For example

www.mysite.com/USERNAME/profile/?urlvar1=true

should be rewritten to

www.mysite.com/profile/?urlvar1=true&userID=1

The rule I have created (below) seems to work but I'm worried that there would be 2 question marks in the URL so for example

www.mysite.com/profile/?urlvar1=true?userID=1

Is this going to be an issue? If so is there a way around this?

<rule name="New Rule 1" enabled="true">
    <match url="^USERNAME/(.*)" />
    <action type="Rewrite" url="{R:1}?userID=1" />
</rule>

Answer 1

It will not be an issue, IIS rewrite module will replace second question mark into &. In your example it will be: /profile?userID=1&urlvar1=true