Creating dynamically linq to EF query with OR predicates

Question

I'm trying to generate LINQ TO Sql query based on input from user. It's pretty simple to create dynamically LINQ Query with AND predicates:

var query = context.Users;

if (age != null)
{
    query = query.Where(x => x.Age == age);
}

if (name != null)
{
   query = query.Where(x => x.Name == name);
}

So if age and name won't be null after all the query will look like this:

query.Where(x => x.Age == age && x.Name == name);

But how to make it, when instead of AND I want it to be OR? I want the final query to be like this:

query.Where(x => x.Age == age || x.Name == name);

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score 0 · Answer 1 · edited Oct 27 '21 at 15:26

The syntax you mentioned for OR is correct.

using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApp3
{
class Program
{
    static void Main(string[] args)
    {
        List<Employee> employees = new List<Employee>
        {
            new Employee { name = "test1", age = 21},
            new Employee { name = "test2", age = 22},
            new Employee { name = "test3", age = 23},
        };

        List<Employee> selectedEmployeesand = employees.Where(x => x.name == "test2" && x.age == 22).ToList();

        Console.WriteLine("using AND");

        foreach (Employee emp in selectedEmployeesand)
        {
            Console.WriteLine(emp.name);
        }

        Console.WriteLine("---------------------------");

        Console.WriteLine("using OR");

        List<Employee> selectedEmployeesor = employees.Where(x => x.name == "test2" || x.age == 21).ToList();

        foreach (Employee emp in selectedEmployeesor)
        {
            Console.WriteLine(emp.name);
        }

        Console.ReadLine();
    }

    public class Employee
    {
        public string name { get; set; }
        public int age { get; set; }
    }
}
}

output:

using AND
test2
---------------------------
using OR
test1
test2

Creating dynamically linq to EF query with OR predicates

1 Answers1