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    copied!<p>You could use PredicateBuilder from <a href="http://www.albahari.com/nutshell/linqkit.aspx" rel="nofollow">LinqKit</a>. It adds some new extension methods to predicate lambdas:</p> <pre><code>var predicate = PredicateBuilder.True&lt;Customer&gt;(); if (searchingFirstName) { predicate = predicate.And(cust =&gt; cust.First == firstName); } if (searchingOrders) { // Some code to unify the .And() and .Or() cases Expression&lt;Func&lt;Order, bool&gt;&gt; subpredicate; Func&lt;Expression&lt;Func&lt;Order, bool&gt;&gt;, Expression&lt;Func&lt;Order, bool&gt;&gt;, Expression&lt;Func&lt;Order, bool&gt;&gt;&gt; joiner; if (orderMethodAny) { subpredicate = PredicateBuilder.True&lt;Order&gt;(); joiner = PredicateBuilder.And; } else { subpredicate = PredicateBuilder.False&lt;Order&gt;(); joiner = PredicateBuilder.Or; } if (searchingOrderDate) { // ... } if (searchingOrderWeight) { switch (orderOp) { case Op.Less: subpredicate = joiner(subpredicate, ord =&gt; ord.Weight &lt; orderWeight); break; case Op.LessEqual: subpredicate = joiner(subpredicate, ord =&gt; ord.Weight &lt;= orderWeight); break; case Op.Equal: subpredicate = joiner(subpredicate, ord =&gt; ord.Weight == orderWeight); break; case Op.GreaterEqual: subpredicate = joiner(subpredicate, ord =&gt; ord.Weight &gt;= orderWeight); break; case Op.Greater: subpredicate = joiner(subpredicate, ord =&gt; ord.Weight &gt; orderWeight); break; case Op.NotEqual: subpredicate = joiner(subpredicate, ord =&gt; ord.Weight != orderWeight); break; } } if (searchingOrderQuantity) { // ... } if (searchingOrderItemName) { // ... } if (searchingOrderPrice) { // ... } predicate = predicate.And(cust =&gt; cust.Orders.Any(subpredicate)); } if (searchingZipCode) { predicate = predicate.And(cust =&gt; cust.ZipCode == zipCode); } var query = Context.Customers.Where(predicate); </code></pre> <p>You might need to call <code>.Expand()</code> on the predicates before passing them as arguments, or <code>.AsExpandable()</code> on the queryable, if you are using the Entity Framework.</p>
 

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