How to update file xml into listview C#

Question

I want to load file xml into listview.But if data on file xml change.Click Button readXML then add data,not update file xml 

File XML:

<?xml version="1.0" ?>

<EMPLOYEES>

<EMP>

<EMPNO>7371</EMPNO>

<ENAME>SMITH</ENAME>

<JOB>CLERK</JOB>

<MGR>7902</MGR>

<HIREDATE>17-DEC-80</HIREDATE>

<SAL>800</SAL>

</EMP>

<EMP>

<EMPNO>7499</EMPNO>

<ENAME>ALLEN</ENAME>

<JOB>SALESMAN</JOB>

<MGR>7698</MGR>

<HIREDATE>20-FEB-81</HIREDATE>

<SAL>1600</SAL>

<COMM>300</COMM>

</EMP>

<EMP>

<EMPNO>7521</EMPNO>

<ENAME>WARD</ENAME>

<JOB>SALESMAN</JOB>

<MGR>7698</MGR>

<HIREDATE>22-FEB-81</HIREDATE>

<SAL>1250</SAL>

<COMM>500</COMM>

</EMP>

<EMP>

<EMPNO>7566</EMPNO>

<ENAME>JONES</ENAME>

<JOB>MANAGER</JOB>

<MGR>7839</MGR>

<HIREDATE>02-APR-81</HIREDATE>

<SAL>2975</SAL>

</EMP>

<EMP>

<EMPNO>7654</EMPNO>

<ENAME>MARTIN</ENAME>

<JOB>SALESMAN</JOB>

<MGR>7698</MGR>

<HIREDATE>28-SEP-81</HIREDATE>

<SAL>1250</SAL>

<COMM>1400</COMM>

</EMP>

</EMPLOYEES>