Datagrid problem

Hi,
I have a datagrid which is bound to a dataset's datatable. my datasource is a xml file. I can display everything in the datagrid, i.e i can read from the xmlfile and write to xml file, but the problem is , if i change a cell value in datagrid, how can i reflect the changes back to dataset. I want my dataset to be updated everytime the user leaves the datagrid.
Can anyone help me out with this

Hello,

I would probably start here to learn about data access in VB. Good luck!

Buddy,
yeh but I will explain my problem in detail

Private Sub dgIncome_Leave(sender, e)

' The code to save changes in datagrid dgIncome as well as new dataset ds1
'I wrote
dgIncome.update()
ds1.Income.AcceptChanges()
ds1.WriteXml("c:\n.xml")
dgIncome.Datasource = ds1.Tables("Income")


End sub

I don't know why my xml file is not populated with the datagrid
could you plz explainme in detail