grid view edit index how to find

protected override void OnInit(EventArgs e)

    {

        base.OnInit(e);

        GridView1.RowEditing += new GridViewEditEventHandler(GridView1_RowEditing);

    }

void Gridview1_RowEditing(object sender, GridViewEditEventArgs e)

    {

         Gridview1.EditIndex = e.NewEditIndex;

    }