Generic method To add sql parameters dynamically for executing sql parameterized query for ado.net

Question

How to add sql parameters dynamically for executing sql parameterized query:

let us say i have a  querytext :" select a,b,c from table1 where  y=@yvalue and
i need to pass this query and the params to one of the db function method and there i have to fetch the data by executing this parameterized query.

at the method call : dbfun.fetchdata(connection ,querytext,params(note:have to send the parameters and values here i.e @xvalue and its value like that here))

at the dbfun class write one method called fetchdata to call the query using parameterized query format.I just wanted to know,how we add those params and values in this method dynamically for adding like

command.parameter.add("@xvalue",its value);
parameter.type=sqldbtype.its data type
parameter.value=some value...

 
Im interested in knowing the method of adding these params and its values and dbtype  dynamically at runtime depending on the param list  ..please help on this.

please note that it should be a generic query,so that if you add some extra parameters later to this query,this method should be able to add those params and fetch the data effectively.