HashSet in C#

In this blog post we are going to learn about HashSet collection in C#. It is a cool collection available from C# 3.5. Like any other collection it can be used for representing a set of value. It is an optimized set collection. It helps eliminating duplicate string or elements in collection. Whenever an Item is added in collection it will check whether this items are already there in collection If not then only it will add items.

Let’s take an example for the same.

using System;
using System.Collections.Generic;

namespace CSharpHashSet
{
    class Program
    {
        static void Main(string[] args)
        { 
            HashSet<string> nameHashSet=
                new HashSet<string>
                {
                    "Jalpesh", "Vishal", "Tushar", "Jalpesh"
                };
            foreach (var item in nameHashSet)
            {
                Console.WriteLine(item);
            }
            Console.ReadKey();
        }
    }
}

Now if you see the code carefully I have created HashSet of name(string type) with duplicate name like “Jalpesh” and then enumerate that collection with for loop and print items of collection with Console.WriteLine.

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StructureMap–Getting Started

In this post we are going to learn about How we can do dependency injection with StructureMap. Here we are going to take a sample application of shopping cart. This shopping cart can process two type of orders 1. Sales order 2. Purchase Order. We want an abstraction for this. So first we are going to create an interface IOrder which will be implemented by both Purchase Order and Sales Order classes.

Following is a code for that.

public interface IOrder
{
    void Process();
}

And following is a implementation of SalesOrder class.

public class SalesOrder : IOrder
{
    public void Process()
    {
        Console.WriteLine("Sales Order Processed");
    }
}

Same way following is a implementation of PurchaseOrder class.

public class PurchaseOrder : IOrder
{
    public void Process()
    {
        Console.WriteLine("Purchase Order Processed");
    }
}

And following is a code for Shopping Cart.

public class ShoppingCart
{
    private readonly IOrder _order;
    public ShoppingCart(IOrder order)
    {
        _order = order;
    }

    public void CheckOut()
    { 
        _order.Process();
    }
}

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Entity Framework Code First migrations

In this blog post we are going to learn about entity code first migrations. Entity Framework code first approach will allow you to define model classes as per the domain requirements via POCOs. Hence you have complete control over classes are written. But as application grows and there are some new features to be added and  your classes will change. Entity Framework Code Migrations allows you to handle this migrations.

As we all now that Entity Framework Code First approach allows you to create database based on your classes created. It’s provide you three types of initializers.

CreateDatabaseIfNotExist: This is the default initializer which will create classes if database not exists.

DropCreateDatabasesWhenModelChanges: This initializer is only good when you don’t concern about your database records. If there is any change in class then it will match database will classes and if there is any difference then it will drop and create a new database.

DropCreateDatabaseAlways: This initializer will always create new database whether database exist or not. If database exist then it will drop that database and create it again.

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