DataGrid 显示选中的item

Datagrid或者listview 中想要把相应的项 滚动到当前可见的位置， 必须满足2个条件：

1） 必须去掉虚拟化

     VirtualizingStackPanel.IsVirtualizing ="False"

2） 调用ScrollToView

       //Bring current selected item to view

            if(null != grdStudyList. SelectedItem && 0 != grdStudyList .Columns. Count)

            {

                //first focus the grid

                grdStudyList.Focus ();

                //then create a new cell info, with the item we wish to edit and the column number of the cell we want in edit mode

                DataGridCellInfo cellInfo = new DataGridCellInfo(grdStudyList .SelectedItem, grdStudyList.Columns [0]);

                //set the cell to be the active one

                grdStudyList.CurrentCell = cellInfo;

                //scroll the item into view

                grdStudyList.ScrollIntoView (grdStudyList. SelectedItem);    

            }         

3)如果不去掉虚拟化， VirtualizingStackPanel.IsVirtualizing ="True"

则， 调用如下语句：

  private void ScrollItemInSelector (Selector dtg, object needScrollItem)

        {

            //Bring current selected item to view

            if (null == dtg && null != needScrollItem )

            {

                //first focus the grid

                dtg.Focus ();

                dtg.SelectedItem = needScrollItem;

                dtg.Items .MoveCurrentTo( needScrollItem);

                ScrollViewer scv = FindVisualChild< ScrollViewer>(dtg );

                if (null != scv

                    && ( dtg.Items .CurrentPosition < scv.VerticalOffset - scv. ViewportHeight || dtg.Items .CurrentPosition > scv.VerticalOffset + scv. ViewportHeight)

                    )

                {

                    scv.ScrollToVerticalOffset (dtg. Items.CurrentPosition );

                }

            }

        }