Groups or outlines a contiguous set of rows.

 public void GroupRows(int startRowIndex, int numRows, boolean collapsed)
Public Sub GroupRows(ByVal startRowIndex As Integer, ByVal numRows As Integer, ByVal collapsed As Boolean)

The 0-based index of the starting row.

The number of rows to group.

Whether or not the group is collapsed.

ws.GroupRows(0, 15, true);
ws.GroupRows(0, 15, True)