use Expression> in Linq contains extension

Question

Using the following example i would like to use my Expression inside my Contains method, having it pass the query onto sql server using the EF.

Answer 1

Isn't the items parameter an IQueryable? If so, try this:

public static IQueryable FilterByCompany(this IQueryable items, Expression> resolveCompanyExpression)
    where T : EntityBase
{
    IQueryable validComps = GetCompaniesFromDataBase();

    var exp = Expression.Lambda>(
        Expression.Call(
            typeof(Queryable),
            "Contains",
            new[] { typeof(Company) },
            Expression.Constant(validComps),
            resolveCompanyExpression.Body
        ),
        resolveCompanyExpression.Parameters[0]
    );
    return items.Where(exp);
}