Data Item of Field Value can be obtained in one by one during rowdatabound event.Don't be confused to run a iteration loop to get each values.If you have 'four' record count of query result it will automatically run in 4 times rowdatabound event.
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
switch (e.Row.RowType)
{
case DataControlRowType.DataRow:
DataRowView myDataRowView = (DataRowView)e.Row.DataItem;
if (String.IsNullOrEmpty(myDataRowView["yourfieldnames"].ToString()))
{
Button status = (Button)e.Row.FindControl("out");
if (status != null)
{
status.visible = false;
}
}
break;
}
}