Write xml with c# ? : I create a form so I use textbox and I would like when I push the button "send" he filled xml :
for exemple 1 time :

    <?xml version="1.0" encoding="utf-8"?>
    <DonneesLocale>
      <Donnee>
        <id>1</id>
        <libelle>bla </libelle>
        <email_asso>bla@</email_asso>
        <login>bla</login>
        <psw>bla</psw>
        <site>bla</site>
        <description>bla</description>
        <data_1_lib></data_1_lib>
        <data_1_val></data_1_val>
        <data_2_lib></data_2_lib>
        <data_2_val></data_2_val>
      </Donnee>
    </DonneesLocale>

and 2nd time when I push the button:

        <?xml version="1.0" encoding="utf-8"?>
    <DonneesLocale>
      <Donnee>
        <id>1</id>
        <libelle>bla </libelle>
        <email_asso>bla@</email_asso>
        <login>bla</login>
        <psw>bla</psw>
        <site>bla</site>
        <description>bla</description>
        <data_1_lib></data_1_lib>
        <data_1_val></data_1_val>
        <data_2_lib></data_2_lib>
        <data_2_val></data_2_val>
      </Donnee>
    <DonneesLocale>
      <Donnee>
        <id>2</id>
        <libelle>hello</libelle>
        <email_asso>hello@</email_asso>
        <login>hello</login>
        <psw>hello</psw>
        <site>hello</site>
        <description>hello</description>
        <data_1_lib></data_1_lib>
        <data_1_val></data_1_val>
        <data_2_lib></data_2_lib>
        <data_2_val></data_2_val>
      </Donnee>
    </DonneesLocale>

Someone can help me please ? 
(Sorry for my English !)
Thanks ! 