Find Rowindex in Row_Command event

you don't need to set anything in e.CommandSource


VB

Dim selectedRow As GridViewRow = DirectCast(DirectCast(e.CommandSource, LinkButton).NamingContainer, GridViewRow)
Dim intRowIndex As Integer = Convert.ToInt32(selectedRow.RowIndex)
GridView.Rows(intRowIndex).BackColor = System.Drawing.Color.Blue

C#

GridViewRow selectedRow = (GridViewRow)((ImageButton)e.CommandSource).NamingContainer;
int intRowIndex = Convert.ToInt32(selectedRow.RowIndex);
GridView.Rows[intRowIndex].BackColor = System.Drawing.Color.Blue;