Sep 14, 2016

Order by with dynamic columns in LINQ c#

Hi Guys, sometimes we need to sort the data dynamically with dynamic column, suppose we are sowing data in grid and after click on column data should be sort, on first click it should be descending and on again click it should be ascending etc. We know that there are no any technique provide by Microsoft so we can resolve this problem to make an Extension Method as follow.
  

using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using System.Threading.Tasks;

namespace DynamicColumnOrderByLinq
{
    public static class ExtMethod
    {
        public static IQueryable<TEntity> CustumOrderBy<TEntity>(this IQueryable<TEntity> source, string ColName, bool desc)
        {
            if (!string.IsNullOrEmpty(ColName))
            {
                string command = desc ? "OrderByDescending" : "OrderBy";
                var type = typeof(TEntity);
                var property = type.GetProperty(ColName);
                var parameter = Expression.Parameter(type, "p");
                var propertyAccess = Expression.MakeMemberAccess(parameter, property);
                var orderByExpression = Expression.Lambda(propertyAccess, parameter);
                var resultExpression = Expression.Call(typeof(Queryable), command, new Type[] { type, property.PropertyType }, source.Expression, Expression.Quote(orderByExpression));
                return source.Provider.CreateQuery<TEntity>(resultExpression);
            }
            else
            {
                return source;
            }
        }
    }
}



Suppose we have a table of Customer as bellow..


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DynamicColumnOrderByLinq
{
    public class CustomerList
    {
        public List<Customer> MyCustomer()
        {
            List<Customer> lst = new List<Customer>(){
            new Customer(){id=1,FirstName="Dilip",LastName="Singh",Email="dilip@gmail.com",Pass="dilip@347",CreateDate=DateTime.Now},
            new Customer(){id=2,FirstName="Vipul",LastName="Bhatt",Email="vipul@gmail.com",Pass="Vipul@347",CreateDate=DateTime.Now},
            new Customer(){id=3,FirstName="Ravi",LastName="Pratap",Email="ravi@gmail.com",Pass="ravi@347",CreateDate=DateTime.Now},
            new Customer(){id=4,FirstName="Pankaj",LastName="Singh",Email="pankaj@gmail.com",Pass="pankaj@347",CreateDate=DateTime.Now},
            new Customer(){id=5,FirstName="Anil",LastName="Singh",Email="anil@gmail.com",Pass="anil@347",CreateDate=DateTime.Now},
            new Customer(){id=6,FirstName="Param",LastName="Tripathi",Email="param@gmail.com",Pass="param@347",CreateDate=DateTime.Now},
            new Customer(){id=7,FirstName="Avnish",LastName="Dubey",Email="avnish@gmail.com",Pass="avnish@347",CreateDate=DateTime.Now}
            };
            return lst;
        }
    }
    public class Customer
    {
        public int id { set; get; }
        public string FirstName { set; get; }
        public string LastName { set; get; }
        public string Email { set; get; }
        public string Pass { set; get; }
        public DateTime CreateDate { set; get; }
    }
}



Now on following code I am trying to sort data according to column and order by descending and ascending.


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using DynamicColumnOrderByLinq;

namespace DynamicColumnOrderByLinq
{
    class Program
    {
        public static void Main(string[] args)
        {
            foreach (var v in cust("FirstName", true))// for ascending false and descending true
            {
                Console.WriteLine("ID= "+v.id + " FirstName ="+v.FirstName+ " LastName = "+
                v.LastName +" Email = "+v.Email+" Pass = "+v.Pass+ " CreateDate ="+v.CreateDate);
            }
        }
        public static List<Customer> cust(string ColumnName,bool OrderBy)
        {
            CustomerList oCust = new CustomerList();
            List<Customer> lst = (from x in oCust.MyCustomer().AsQueryable()
            select x).CustumOrderBy(ColumnName, OrderBy).ToList();
            return lst;
        }
    }
}



Note: If you want to sort descending order by column then pass parameter true and if you want to sort ascending order by column then pass false.

For descending


            foreach (var v in cust("FirstName", true))// for descending true
            {
                Console.WriteLine("ID= "+v.id + " FirstName ="+v.FirstName+ " LastName = "+
                v.LastName +" Email = "+v.Email+" Pass = "+v.Pass+ " CreateDate ="+v.CreateDate);
            }



For ascending


            foreach (var v in cust("FirstName", false))// for ascending true
            {
                Console.WriteLine("ID= "+v.id + " FirstName ="+v.FirstName+ " LastName = "+
                v.LastName +" Email = "+v.Email+" Pass = "+v.Pass+ " CreateDate ="+v.CreateDate);
            }




You can down load code from here..

Aug 9, 2016

Query to subtract in MongoDB

We can use $subtract operator to subtract tow numbers. $subtract is arithmetic aggregation operator which subtract two number and returns the difference.

$subtract can be use to get differences between dates means we can subtract date also, $subtract treat to second number as millisecond if first number is date type.

Syntax:


{ $subtract: [ <expression1>, <expression2> ] }


Example: Suppose we have a collection “Inventory” as below and before show the details of product on our website we need to calculate total price in our query.


{
            _id:1,
            Title:"Title1",
            SKU:"1234567890123",
            Price:20.50,
            ShippingCharge:4.80,
            Discount:2.00,
            CreatedDate:ISODate("2016-08-09T013:00:00Z")
}
{
            _id:2,
            Title:"Title2",
            SKU:"1234567890121",
            Price:30.50,
            ShippingCharge:4.80,
            Discount:2.00,
            CreatedDate:ISODate("2016-08-09T013:00:00Z")
}
{
            _id:3,
            Title:"Title3",
            SKU:"1234567890122",
            Price:50.50,
            ShippingCharge:4.80,
            Discount:2.00,
            CreatedDate:ISODate("2016-08-09T013:00:00Z")
}


See the following query here we calculating the discounted price. We are adding Price and ShippingCharge and subtract discounted price.


db.Inventory.aggregate(
[
            { $project:
                        { Title: 1,SKU:1, Discounted_Price:
                                    { $subtract:
                                                [ { $add: [ "$Price", "$ShippingCharge" ] }, "$Discount" ]
                                    }
                        }
            }
] )


Result:


/* 1 */
{
    "_id" : 1,
    "Title" : "Title1",
    "SKU" : "1234567890123",
    "Discounted_Price" : 23.3
}

/* 2 */
{
    "_id" : 2,
    "Title" : "Title2",
    "SKU" : "1234567890121",
    "Discounted_Price" : 33.3
}

/* 3 */
{
    "_id" : 3,
    "Title" : "Title3",
    "SKU" : "1234567890122",
    "Discounted_Price" : 53.3
}


Same like that if you want to subtract date you can use $subtract operator.

Subtract one day from CreatedDate
See following query which is subtracted one day from CreatedDate.


db.Inventory.aggregate(
[
            { $project:
                        { Title: 1,SKU:1, Sub_Date:
                                    { $subtract:
                                                [ "$CreatedDate", 24*60*60*1000 ]
                                    }
                        }
            }
] )


Result:


/* 1 */
{
    "_id" : 1,
    "Title" : "Title1",
    "SKU" : "1234567890123",
    "Sub_Date" : ISODate("2016-08-08T01:00:00.000Z")
}

/* 2 */
{
    "_id" : 2,
    "Title" : "Title2",
    "SKU" : "1234567890121",
    "Sub_Date" : ISODate("2016-08-08T01:00:00.000Z")
}

/* 3 */
{
    "_id" : 3,
    "Title" : "Title3",
    "SKU" : "1234567890122",
    "Sub_Date" : ISODate("2016-08-08T01:00:00.000Z")
}