how to get matching value in xml file and display in textbox

Question

Hi friends,
 
i have xml file like
<data1>
 <R_ID>101</R_ID>
<R_PRE>30</R_PRE>
<R_PRE2>34</R_PRE2>
<R_TEMP>6.12</R_TEMP>
 <R_TENP2>3.64</R_TENP2>
</data1>
<data1>
<R_ID>101</R_ID>
 <R_PRE>28</R_PRE>
 <R_PRE2>33</R_PRE2>
 <R_TEMP>6.02</R_TEMP>
<R_TENP2>3.90</R_TENP2>
 </data1> <data1>
<R_ID>101</R_ID>
 <R_PRE>26</R_PRE>
<R_PRE2>32</R_PRE2>
<R_TEMP>5.63</R_TEMP>
 <R_TENP2>4.05</R_TENP2>
 </data1>
<data1>
<R_ID>101</R_ID>
<R_PRE>24</R_PRE>
<R_PRE2>31</R_PRE2>
<R_TEMP>5.25</R_TEMP>
 <R_TENP2>4.82</R_TENP2>
</data1>
<data1>
 <R_ID>101</R_ID>
<R_PRE>22</R_PRE>
 <R_PRE2>30</R_PRE2>
 <R_TEMP>4.26</R_TEMP>
 <R_TENP2>5.05</R_TENP2>
 </data1> ......................
and then i have Two TextBoxes and One Button
i am enter a value in text box1 then i click button it ll go and get the matching value and display textbox2.
 
for example in above xml file i enter txtbox1(30) and i click button I want to dispaly textbox2(6.12)
txtbox(28) ....txtbox2(6.02)....like that
 
please give me any idea how to match and get it.
 
Thanks
Venkat.S