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    <p>In order to avoid using generics (since the types are not known at design time) you could use some reflection and build the expression "by hand"</p> <p>You would need to do this by defining a "Contains" expression inside one Where clause:</p> <pre><code>public IQueryable GetItemsFromContainsClause(Type type, IEnumerable&lt;string&gt; items) { IUnitOfWork session = new SandstoneDbContext(); var method = this.GetType().GetMethod("ContainsExpression"); method = method.MakeGenericMethod(new[] { type }); var lambda = method.Invoke(null, new object[] { "Codigo", items }); var dbset = (session as DbContext).Set(type); var originalExpression = dbset.AsQueryable().Expression; var parameter = Expression.Parameter(type, ""); var callWhere = Expression.Call(typeof(Queryable), "Where", new[] { type }, originalExpression, (Expression)lambda); return dbset.AsQueryable().Provider.CreateQuery(callWhere); } public static Expression&lt;Func&lt;T, bool&gt;&gt; ContainsExpression&lt;T&gt;(string propertyName, IEnumerable&lt;string&gt; values) { var parameterExp = Expression.Parameter(typeof(T), ""); var propertyExp = Expression.Property(parameterExp, propertyName); var someValue = Expression.Constant(values, typeof(IEnumerable&lt;string&gt;)); var containsMethodExp = Expression.Call(typeof(Enumerable), "Contains", new[] { typeof(string) }, someValue, propertyExp); return Expression.Lambda&lt;Func&lt;T, bool&gt;&gt;(containsMethodExp, parameterExp); } </code></pre> <p>In this case "Codigo" is hard-coded, but it could be a parameter to get any property of the type you define.</p> <p>You could test it by using:</p> <pre><code>public void LambdaConversionBasicWithEmissor() { var cust= new Customer(); var items = new List&lt;string&gt;() { "PETR", "VALE" }; var type = cust.GetType(); // Here you have your results from the database var result = GetItemsFromContainsClause(type, items); } </code></pre>
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    1. POReflection to call generic method with lambda expression parameter
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    1. USGabriel Vonlanten C. Lopes
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    1. COI used your code (for Queryable) to apply the solution for Entity Framework DbSet query, that is to use the DbSet original expression like dbset.AsQueryable().Expression in the Where clause, used by the CreateQuery method of the DbSet QueryableProvider. This way, EF will internally generate a perfect SQL IN clause. BTW, some parts of your code (e.g. MakeGenericMethod line) could be converted to pure Expression instead of the Reflection approach. Thank you!
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