Sets or returns the 0-based number of the first row within the rectangular area of cells.

 public int FirstRow{ get; }
Public ReadOnly Property FirstRow() As Integer

//--- Get FirstRow
int row = a.FirstRow;

//--- Set FirstRow
a.FirstRow = 5;

'--- Get FirstRow
Dim row As Integer = a.FirstRow

'--- Set FirstRow
a.FirstRow = 5