Regular Expression - partial match of string

I have the following pattern I am using to not allow the username to be used in the password.  This isn't working.

pattern = @"^.*(?=.*[A-Z])(?=.*[a-z])(?<"+txtUserName.Text+@">.*)(?=.*[@#$%^&+=]|.*\d)^.{8,32}.*$";

Please provide assistant in getting this pattern corrected to disallow the username to be used.
Ie.  Username = testuser
     Password could not be   123 testuser123

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pattern = "^.*" +  txtUserName.Text + ".*$" ;

. means any characters
* means 0 or more times

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shugt23Author Commented:
Perfect.  Works great.  
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