when i want to print IEnumerable to console screen then i'm getting "System.Collections.Generic.List`1[Linq_1.Objects.UserObject]"

Question

I'm trying to learn Ienumerable with linq.

What I want to do is to print the userlist after filtering it with linq. But I am encountering such a console screen.

Main Code:

class Program
{
    static void Main(string[] args)
    {
        LinqExtensions<UserObject> linq = new LinqExtensions<UserObject>();
        var users = new List<UserObject>()
        {
           new UserObject()
           {
               Id=1,
               FirstName="xx",
               LastName="yy",
               EmailAdress="[email protected]",
               CreateDateTime=DateTime.Now
           },
           new UserObject()
           {
               Id=2,
               FirstName="aa",
               LastName="bb",
               EmailAdress="[email protected]",
               CreateDateTime=DateTime.Now
           }
        };
        
        var userList = linq.Where_EqualsEvenID(users);
        Console.WriteLine(userList);
        Console.ReadLine();
    }
}

And Extensions Code:

    public class LinqExtensions <T> where T:UserObject
{
    
    public IEnumerable<T> Where_EqualsEvenID(IEnumerable<T> TTypeIEnum)
    {
        return TTypeIEnum.Where(p => p.Id % 2 != 0).ToList();
    }
    public IEnumerable<T> Where_OddEvenID(IEnumerable<T> TTypeIEnum)

    {
        return TTypeIEnum.Where(p => p.Id % 2 != 0).ToList();
    }
    
    public IEnumerable<T> Where_EqualsId(IEnumerable<T> TTypeIEnum,int id)
    {
        return TTypeIEnum.Where(p=>p.Id==id).ToList();
    }
}

Console ScreenShot

Console Message: System.Collections.Generic.List`1[Linq_1.Objects.UserObject]

Help me please, thanks a lot.

Answer 1

Why are you getting the type text instead of values?

• Console.WriteLine(Object) writes the text representation of an object.
• To represent the object into text, it calls .ToString() method.
• If it is not overridden in your class, then it invokes .ToString() default implementation.
• This default implementation is nothing but returning the string representation of the current object

---

How to fix your issue?

To fix this issue, you override ToString() within the UserObject class.

public class UserObject
{
   ...

   public override string ToString()
   { 
       //You can include fields as per your need.
       return $"{this.FirstName} {this.LastName}";
   }  
}

Now while printing the list of UserObject, you need to iterate over each object of UserObject and print the details.

foreach(var userObj in userList)
   Console.WriteLine(userObj);  

You can also use string.Join(),

Console.WriteLine(string.Join(Environment.NewLine, userList));

This will print

xx yy
aa bb

Answer 2

You have to loop IEnumerable collection and use Json serialized(add Newtonsoft.Json extension to your project) to convert and print object in console.

Check below code

using Newtonsoft.Json;


namespace SampleExample
{
    internal class Program
    {
        static void Main(string[] args)
        {
            LinqExtensions<UserObject> linq = new LinqExtensions<UserObject>();
            var users = new List<UserObject>()
        {
           new UserObject()
           {
               Id=1,
               FirstName="xx",
               LastName="yy",
               EmailAdress="[email protected]",
               CreateDateTime=DateTime.Now
           },
           new UserObject()
           {
               Id=2,
               FirstName="aa",
               LastName="bb",
               EmailAdress="[email protected]",
               CreateDateTime=DateTime.Now
           },
           new UserObject()
           {
               Id=3,
               FirstName="zak",
               LastName="tos",
               EmailAdress="[email protected]",
               CreateDateTime=DateTime.Now
           },
           new UserObject()
           {
               Id=4,
               FirstName="Michael",
               LastName="J",
               EmailAdress="[email protected]",
               CreateDateTime=DateTime.Now
           }
        };

            var userList = linq.Where_EqualsEvenID(users);

            foreach (var item in userList)
            {
                Console.WriteLine(JsonConvert.SerializeObject(item, Formatting.Indented));
            }
            Console.ReadLine();
        }

        public class LinqExtensions<T> where T : UserObject
        {
            public IEnumerable<T> Where_EqualsEvenID(IEnumerable<T> TTypeIEnum)
            {
                return TTypeIEnum.Where(p => p.Id % 2 == 0).ToList();
            }
            public IEnumerable<T> Where_OddEvenID(IEnumerable<T> TTypeIEnum)

            {
                return TTypeIEnum.Where(p => p.Id % 2 != 0).ToList();
            }

            public IEnumerable<T> Where_EqualsId(IEnumerable<T> TTypeIEnum, int id)
            {
                return TTypeIEnum.Where(p => p.Id == id).ToList();
            }
        }
        public static void localmethod1(object a, object b)
        {
            Console.WriteLine("Local method." + a + "-" + b);
        }

        public static void DisplayNumbers(int min, int max)
        {

            Console.WriteLine("DisplayNumbers :" + (min + max));
        }
    }

    public class UserObject
    {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string EmailAdress { get; set; }
        public DateTime CreateDateTime { get; set; } = DateTime.Now;
    }
}

Result

enter image description here