hello professional
you just need to concatenate your both columns as DB level and then bind them
from your Combo box.
like this
1st make a query in sql-
select (+'( '+ cast(BookNumber as varchar(20)) +' ) ' + BookName) as BookNameCode from T_BookMaster
here casting (cast(BookNumber as varchar(20))) because i think in DB's BookNumber Column may be Int type data type
then youn need to simple bind it
like this-
CmbBook.DataSource = dsbook;
CmbBook.DataTextField = "BookNameCode ";
CmbBook.DataValueField = "BookNumber";
CmbBook.DataBind();
Happy To Help!!!