Difference between IEnumerable,IQueryable VS List

 First the difference between List<T>, IEnumerable<T> and IQueryable<T>.

 The content of List<T> will always be loaded into memory, because it uses an array in the background.

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The content of IEnumerable<T> will only load the requested item into the memory. Compiler sets up a state machine during compiling a method with IEnumerable<T> that has a yield return T. So only one item at a time will be loaded into memory in this case.

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IQueryable<T> is "special" version of IEnumerable<T>. Specifically designed to query data sources, and implemented by data providers. Like EF, NHibernate. So when you tell EF to fetch the data with .ToListAsync<T>() EF will only then go the database and execute the generated query. See the docs for more info about IQueryable<T>.

C# Enum Value and Display name Extension

using System;

using System.Collections.Generic;

using System.ComponentModel.DataAnnotations;

using System.Linq;

using System.Reflection;

using System.Runtime.Serialization;

using System.Web;

namespace Helper.Extensions

{

    public static class EnumExtensions

    {

        public static string GetEnumValue(this Enum enumValue)

        {

            var type = enumValue.GetType();

            var info = type.GetField(enumValue.ToString());

            if (info == null) return string.Empty;

            var da = (EnumMemberAttribute[])

                    (info.GetCustomAttributes(typeof(EnumMemberAttribute), false));

            if (da.Length > 0)

                return da[0].Value;

            else

                return string.Empty;

        }

        public static string GetDisplayName(this Enum enumValue)

        {

            return enumValue.GetType()

                            .GetMember(enumValue.ToString())

                            .First()

                            .GetCustomAttribute<DisplayAttribute>()

                            .GetName();

        }

    }

}

C# simple example for recursive call

using System;

class HelloWorld {

  static void Main() {

      var result=print(0);

    Console.WriteLine(result);

  }

  public static string print(int count)

  {

      return print2(count);

  }

  public static string print2(int count)

  {

      if(count <= 2)

      {

          Console.WriteLine(count);

          count++;

          //recursive call upto 3count

          return print(count);

      }

     

      return "Recursive final return";

  }

}

//output like below

0

1

2

Recursive final return

Mapster over AutoMapper for mapping objects in c# Crud

1.Add Mapster packages from NuGet

<package id="Mapster" version="7.3.0" targetFramework="net48" />

<package id="Mapster.Core" version="1.2.0" targetFramework="net48" />

2.Create Source class

//Source or DTO

public class TempCacheDto

    {

        public int Id { get; set; }

        public string SerialNumber { get; set; }

    }

3.Create Destination class

//Destination or Entity Db object

public class TempCache

    {

        public int Id { get; set; }

        public string SerialNumber { get; set; }

    }

4.Create Service or repository class where mapping required to convert Dto to Enity object.

Simple Save and Retrieve example below for using mapster and entity framework.

using Mapster;

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace TempCache.Repositories

{

    public class TempCacheRepository

    {

//save data from dto model to entity using mapster        

        public bool Save(TempCacheModel bcTempCache)

        {

            using (var context = new DbContext())

            {

                if (bcTempCache.Id == 0)

                {

                    TempCache entity = bcTempCache.Adapt<TempCache>();

                    context.TempCaches.Add(entity);

                }

                else

                {

                    TempCache exist = context.TempCaches

                                        .FirstOrDefault(x => x.Id == bcTempCache.Id);

                    if (exist != null)

                    {

                        exist = bcTempCache.Adapt<TempCacheModel, TempCache>(exist);

                    }

                    else

                    {

                        return false;

                    }

                }

                context.SaveChanges();

                return true;

            }

        }

//get list from Db and retun as dto list using mapster

        public List<TempCacheModel> TempCaches()

        {

            using (var context = new DbContext())

            {

                return context.TempCaches.ToList().Adapt<List<TempCacheModel>>();

            }

        }

//get list from Db and retun as dto list using mapster        

        public TempCacheModel GetById(int id)

        {

            using (var context = new DbContext())

            {

                return context.TempCaches.FirstOrDefault(x=>x.Id==slNo)?

                        .Adapt<TempCacheModel>();

            }

        }

    }

}

Why Mapster over Auto mapper

Method	Mean	StdDev	Error	Gen 0	Gen 1	Gen 2	Allocated
'Mapster 6.0.0'	108.59 ms	1.198 ms	1.811 ms	31000.0000	-	-	124.36 MB
'Mapster 6.0.0 (Roslyn)'	38.45 ms	0.494 ms	0.830 ms	31142.8571	-	-	124.36 MB
'Mapster 6.0.0 (FEC)'	37.03 ms	0.281 ms	0.472 ms	29642.8571	-	-	118.26 MB
'Mapster 6.0.0 (Codegen)'	34.16 ms	0.209 ms	0.316 ms	31133.3333	-	-	124.36 MB
'ExpressMapper 1.9.1'	205.78 ms	5.357 ms	8.098 ms	59000.0000	-	-	236.51 MB
'AutoMapper 10.0.0'	420.97 ms	23.266 ms	35.174 ms	87000.0000	-	-	350.95 MB