Insert Row to DataGrid

[Jawed Hadi]

Hi
I have two questions (problems)
1.
I am using the following code to add a new Row. It does add a new row to my Datagrid and it lets me add data to it, when I move to the next row it deletes all the data from this new row and moves the blank row one down and replaces it with the older row. Then it does not accept any data when you write into the cells of this row. Maybe I need to add some extra line of code to this. Can some help please? Thanks

Dim dr as Datarow
Dim dt as New Datatable() = mydataSet.tables(0)

dr = dt.NewRow
If myGrid.IsSelected(myGrid.CurrentRowIndex) Then
dt.Rows.InsertAt((dr, myGrid.CurrentRowIndex)
dt.AcceptChages()
Else
msgBox("Select a row first")
End If

2.
If I close my data Grid Window how can I know whether my Data Grid was Modified?

Thanks for taking the time to help