RadGridView scroll postion works with real numbers only

Greetings,

         I am interested in knowing why code 1 works but code 2 below does not in repositioning the scroll on a RadGridView. Also, any posibile solution as to why code 2 does not work would be appreciated. Thank you.

Works:

Code 1 : dvTrackingLog.TableElement.ScrollTo(30, 0);

Code 1a: dvTrackingLog.CurrentRow = dvTrackingLog.Rows[30];

AutoScrollGrid(30);

Code 1b: dvTrackingLog.TableElement.ScrollTo(rowIndex, 0);

Code 1c: dvTrackingLog.CurrentRow = dvTrackingLog.Rows[rowIndex];

Does not work:

Code 2: dvTrackingLog.TableElement.ScrollTo(dvTrackingLog.SelectedRows[0].Index, 0);

Code 2a: dvTrackingLog.CurrentRow = dvTrackingLog.Rows[dvTrackingLog.SelectedRows[0].Index];

AutoScrollGrid(rowIndex);

Code 2b: dvTrackingLog.TableElement.ScrollTo(rowIndex, 0);

Code 2c: dvTrackingLog.CurrentRow = dvTrackingLog.Rows[rowIndex];