c# - Regular expression - extract 6 digits exactly -

YAV - edited to be clear

Hello, I want to find 6-digit numerical strings in text File Required Example:

  Text text text 123365 text text text   
 Expression should now leave strings 6:  
  text text text 1233656 text text text   
 The above string should not return any result because the length of the digit string is 7.  
 I came up with this expression:  [^ 0- 9] ([0- 9]) {6} [^ 0-9]   
 It works perfectly with the exception of the string which is at the beginning or end  
  123365 text text text text text text text text text 123365   < P> Is it possible to identify these cases?   
 
 
 Try:  
  (? & Lt ;! \ D ) \ D {6} (?! \ D)   
 It says:  
 
 Find 6 digits, which have not gone further Or are not successful with a single digit   
 This will appear anywhere in the string.  
 Example:  
 
 123365 text text text text text text text text text 123365   
 matchbox 123365  
 123365   
 
 123365 text text 234098 text text text text text text text 567890 text 123365   
 
 123365  
 234098  
 567890  
 123365