"Multiple" XML-File (new input should not replace) using c# -

i'm writing short program displays me do's. got 2 tabs. 1 tab create new , other tab displaying me details of every selected. have save created do's in xml file. using datatable , dataset , works fine. here code:

datatable datatable = new datatable();             datatable.tablename = "saveinput";              datacolumn dc1 = new datacolumn("name");             datacolumn dc2 = new datacolumn("priority");             datacolumn dc3 = new datacolumn("startdate");             datacolumn dc4 = new datacolumn("enddatesoll");             datacolumn dc5 = new datacolumn("enddateist");             datacolumn dc6 = new datacolumn("comment");              datatable.columns.add(dc1);             datatable.columns.add(dc2);             datatable.columns.add(dc3);             datatable.columns.add(dc4);             datatable.columns.add(dc5);             datatable.columns.add(dc6);              datatable.rows.add(txt_name.text, combox_priority.text, txt_beginn.text, txt_endsoll.text, txt_endist.text, txt_bemerkungen.text);              dataset dataset = new dataset();              dataset.tables.add(datatable);             dataset.datasetname = "myprogram";              dataset.writexml(@"c:\users\rs\desktop\test\save.xml"); 

but problem is: if create new "to do" in tab1, replace new "to do" in .xml file. if have @ .xml file, there still 1 "to do". want write more tables in .xml file. .xml file looks this:

<myprogram>   <saveinput>     <name>todo1</name>     <priority>high</priority>     <startdate>today</startdate>     <enddatesoll>later</enddatesoll>     <enddateist>not finished</enddateist>     <comment>blabla</comment>   </saveinput> </myprogram> 

but should example:

<myprogram>   <saveinput>     <name>todo1</name>     <priority>high</priority>     <startdate>today</startdate>     <enddatesoll>later</enddatesoll>     <enddateist>not finished</enddateist>     <comment>blabla</comment>      <name>todo2</name>     <priority>high</priority>     <startdate>yesterday</startdate>     <enddatesoll>tomorrow</enddatesoll>     <enddateist>not finished</enddateist>     <comment>testtest</comment>   </saveinput> </myprogram> 

i hope can me or give me hint can create more 1 to-do.

cheers

edit: it's winform application

this code should work you.

check out

dataset ds = new dataset();             if (file.exists(@"c:\users\rs\desktop\test\save.xml"))             {                 ds.readxml(@"c:\users\rs\desktop\test\save.xml");                  ds.tables[0].rows.add(txt_name.text, combox_priority.text, txt_beginn.text, txt_endsoll.text, txt_endist.text, txt_bemerkungen.text);                 ds.writexml(@"c:\users\rs\desktop\test\save.xml");             }             else             {                 datatable datatable = new datatable();                 datatable.tablename = "saveinput";                  datacolumn dc1 = new datacolumn("name");                 datacolumn dc2 = new datacolumn("priority");                 datacolumn dc3 = new datacolumn("startdate");                 datacolumn dc4 = new datacolumn("enddatesoll");                 datacolumn dc5 = new datacolumn("enddateist");                 datacolumn dc6 = new datacolumn("comment");                  datatable.columns.add(dc1);                 datatable.columns.add(dc2);                 datatable.columns.add(dc3);                 datatable.columns.add(dc4);                 datatable.columns.add(dc5);                 datatable.columns.add(dc6);                  datatable.rows.add(txt_name.text, combox_priority.text, txt_beginn.text, txt_endsoll.text, txt_endist.text, txt_bemerkungen.text);                  dataset dataset = new dataset();                  dataset.tables.add(datatable);                 dataset.datasetname = "myprogram";                  dataset.writexml(@"c:\users\rs\desktop\test\save.xml");             }