Getting Gridview Row Index in Row Command Event

GridViewRow rowSelect = (GridViewRow)(((ImageButton)e.CommandSource).NamingContainer);
int i = rowSelect.RowIndex;

OR

GridViewRow rowSelect = ((ImageButton)sender).Parent.Parent as GridViewRow;
int i = rowSelect.RowIndex;

OR

Bind in Button CommandArgument
((GridViewRow) Container).RowIndex

OR
GridView Row index by control
CheckBox chkBox = (CheckBox) sender;
GridViewRow gRow = (GridViewRow)chkBox.NamingContainer;