IQueryable OfType where T is a runtime Type

Question

I need to be able to get something similar to the following to work:

Type type = ??? // something decided at runtime with .GetType or typeof;
object[] entity         


        

Answer 1

A solution to handle multiple types is

        public static IQueryable OfTypes(this DbSet query, IEnumerable types )  where TEntity : class
            {
                    if( types.Count() == 0 ) return query;

                    var lambda = GetOfOnlyTypesPredicate( typeof(TEntity), types.ToArray() );
                    return query.OfType().Where( lambda as Expression>);

            }


            public static LambdaExpression GetOfOnlyTypesPredicate( Type baseType, Type[] allowed )
            {
                    ParameterExpression param = Expression.Parameter( baseType, "typeonlyParam" );
                    Expression merged = Expression.TypeIs( param, allowed[0] );
                    for( int i = 1; i < allowed.Length; i++ )
                            merged = Expression.OrElse( merged, Expression.TypeIs( param, allowed[i] ));
                    return Expression.Lambda( merged, param );