If you are searching your control in all Rows then you should use
OnRowDataBound
event of GridView this method takes
GridViewRowEventArgs
as a parameter with Object.
protected void gridview_OnRowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
}
}
Hope it will help you.
Good luck.
--Rajesh