c# - Retrieve single value from Database, much like DLookup() in MS Access -

i exploring silverlight (c#) , sqlserver next evolution our current (slow) access database. far has been great, using domainservices retrieve data need. in our database have table (supervisors) supervisor_id, supervisor_firstname, supervisor_lastname , many other fields.

what want recreate function use in current database called entitynamefirstlast(entityid) take integer. retrieve value of [supervisor_firstname] [supervisors] table [supervisor_id] == entityid using following: firstname = dlookup("[supervisor_firstname]", "supervisors", "[supervisor_id] = entityid

i same lastname , combine strings returning 1 string first , last name.

how can single value database through domainservice (or way matter)? understand iqueryable getsupervisorbyid(int supid) return entire row need, how can specific field row?

i aware can set domaindatasource in xaml , bind data want, curious if asked above doable or not.

there number of ways can accomplish requirement if need single value ms-sql server:

1.use query concatenation , use output in code

select supervisor_firstname + ' ' + supervisor_lastname supervisor_fullname supervisors supervisor_id = entityid 

now can above query execute through sqlcommand , part thats interesting you

private string getsupervisorfullname(string entityid, string connectionstring) {     string query = "select supervisor_firstname + ' ' + supervisor_lastname supervisor_fullname supervisors supervisor_id = @entityid";     string supervisorfullname = "";      using(sqlconnection con = new sqlconnection(connectionstring)) {         sqlcommand cmdsupervisorfullname = new sqlcommand();         cmdsupervisorfullname.connection = con;         cmdsupervisorfullname.commandtext = query;         cmdsupervisorfullname.commandtype = commandtype.text;          sqlparameter paraentityid = new sqlparameter();         paraentityid.parametername = "@entityid";         paraentityid.sqldbtype = sqldbtype.nvarchar;         paraentityid.direction = parameterdirection.input;         paraentityid.value = entityid;          cmdsupervisorfullname.parameters.add(paraentityid);          try {             con.open();             supervisorfullname = (string) cmdsupervisorfullname.executescalar();         } catch(exception ex) {             console.writeline(ex.message);         }          return supervisorfullname;     } } 

2.second way create scalar function in sql requirement , access function using same kind of method mentioned above.

then take return value method getsupervisorfullname , populate control value of choice.

please note there again other methods of doing same linqtosql or other orm tools. above 2 methods basic way of accomplishing them.

hope helps.