WPF C# datagrid fix view row (fix scroll)

i am working on WPF datagrid and want to fix view after insert row at top, whenever row insert at top view scroll down by 1 row, i am using following code

int i =0;DataTable dt =null;privatevoidUserControl_Loaded(object sender,RoutedEventArgs e){
        dt =newDataTable();
        dt.Columns.Add("Col1");
        dt.Columns.Add("Col2");DispatcherTimer dtimer =newDispatcherTimer();
        dtimer.Tick+=newEventHandler(dt_Tick);
        dtimer.Interval=newTimeSpan(0,0,1);
        dtimer.Start();
        dataGrid1.DataContext= dt;}void dt_Tick(object sender,EventArgs e){DataRow dr;
        dr = dt.NewRow();
        dr["Col1"]= i;
        dr["Col2"]= i;
        dt.Rows.InsertAt(dr,0);
        i++;}

i tried to use dataGrid1.ScrollIntoView(dataGrid1.SelectedItem); but it still need selected item, and even it scroll down till last row in view

I can manage to do the same in DataGridView of windows form in following way

DataGridViewCell cell = dataGridView1.FirstDisplayedCell;
dt.Rows.InsertAt(dr,0);
dataGridView1.FirstDisplayedCell= cell;

looking for any similar ways to do this in WPF also

Thanks.