pass parameter from asp page to xslt file

See more:

C#

ASP.NET

i have 1 asp page . this page view the content of 1 xml file : "SinhVien.xml".
Then, in the asp page i have 1 textbox "txtMaSV" for get the data input and 1 button "btnTim".
when user type the id in the txtMaSV and click btnTim, it pass the id from asp page to xslt file. in xslt file , it get the id of asp and usr for browse.
for example : <xsl:for-each select="SinhVien.xml/SinhVien" xmlns:xsl="#unknown">
<xsl:value-of select="[MASV=id">
i don't know how to pass the id from asp page to xslt file, and get it from xslt file.
give me your idea, thanks!