Page is not scrolling upto last element(TextBox) when keyboard pops up

   xaml code:
       <Grid x:Name="LayoutRoot" Background="Transparent">
                       <controls:Pivot x:Name="rootPivot" >
            </controls:Pivot>
        </Grid>
     background code:
               var pivotItem = new PivotItem();
                pivotItem.Header = pageTitle;
                ScrollViewer scrollViewer = new ScrollViewer();
                scrollViewer.Content = formGrid    (another grid which contains elements (TextBoxes))
                pivotItem.Content = scrollViewer;
                rootPivot.Items.Add(pivotItem);

Suppose if there are 10 textboxes in that PivotItem,I will enter the text in the first textbox. then I want to scroll the page upto last textbox with out closing the KeyBoard.But I could not scroll the page upto last textbox.

I can enter the text in last textbox if i close the keyboard.But my requirement is to scroll upto last textbox with out closing the keyboard. Please let me know how to do it?