How do I implement a dynamic 'where' clause in LINQ?

Question

I want to have a dynamic where condition.

In the following example:

var opportunites =  from opp in oppDC.Opportunities
                        


        

Answer 1

If you know in advance all possible where queries like in the SQL example you have given you can write the query like this

from item in Items
where param == null ? true : ni.Prop == param
select item;

if you don't know all possible where clauses in advance you can add where dymically for example like this:

query = query.Where(item => item.ID != param);