ADOQuery1.Close;
ADOQuery1.SQL.Clear;
ADOQuery1.SQL.Add('select * from table where 字段='''+ComboBox1.Text+'''');
ADOQuery1.Open;

if ADOQuery1.RecordCount=1 then
begin
  Edit1.Text := ADOQuery1.FieldByName('字段1').AsString;
  Edit2.Text := ADOQuery1.FieldByName('字段2').AsString;
........
end;