Using a thread-safe dictionary in .NET C# Part 1: introduction

July 28, 2015 1 Comment

In this post we saw how to use the thread-safe counterpart of the Queue object, i.e. the ConcurrentQueue of T. The standard Dictionary class also has a thread-safe counterpart and it’s called ConcurrentDictionary which resides int the System.Collections.Concurrent namespace.

The ConcurrentDictionary is definitely a dictionary type but it can mimic other collection types if you need a thread-safe collection that doesn’t have a built-in concurrent counterpart such as a List. ConcurrentDictionary is more difficult to use than a standard dictionary so its usage cannot really be summarised in a single short post. Therefore we’ll go through the basics in a mini-series instead.

It implements the IDictionary interface just like Dictionary but some methods are hidden:

Read more of this post

Filed under .NET, C# language features, Task Parallel Library Tagged with , , ,

Implementing an enumerator for a custom object in .NET C#

July 24, 2015 Leave a comment

You can create an enumerator for a custom type by implementing the generic IEnumerable of T interface. Normally you’d do that if you want to create a custom collection that others will be able to iterate over using foreach. However, there’s nothing stopping you from adding an enumerator to any custom type if you feel like it, it’s really simple.

Consider the following Guest class:

public class Guest
{
	public string Name { get; set; }
	public int Age { get; set; }
}

Guests can be invited to a Party:

Read more of this post

Filed under .NET, C# language features, Generics Tagged with ,

Using a thread-safe queue collection in .NET

July 22, 2015 Leave a comment

We looked at the Queue collection type in .NET in this post. We saw how it could be used as a first-in-first-out collection. A new element is placed at the end of the queue and the first element to be removed from it is the one in front of the queue.

A Queue is an ideal container for tasks. Let’s create a class called WorkTask to represent tasks. I didn’t want to call this object a “Task” so that it is not confused with the Task object in the Task Parallel Library (TPL). If you don’t know what TPL means then take a look at the post referenced at the end of this article.

Read more of this post

Filed under .NET, C# language features, Task Parallel Library Tagged with , , , ,

Thread-safe bags in .NET

July 21, 2015 1 Comment

Bags are very similar to Stacks and Queues. We saw that both stacks and queues order their elements in a well defined way: last-in-first-out and first-in-first-out respectively. Bags on the other hand are unordered collections. There’s no guarantee on how, i.e. in which order the elements will be retrieved.

Unlike stacks and queues, bags have no one-to-one single-threaded implementation in .NET. They are however implemented as thread-safe ConcurrentBag objects in the System.Collections.Concurrent namespace.

Read more of this post

Filed under .NET, C# language features, Task Parallel Library Tagged with , , ,

Structurally compare two arrays in .NET

July 17, 2015 Leave a comment

In this post we saw how to determine if two arrays are structurally equal in .NET. Two arrays are said to be structurally equal if they contain the same elements in the same order.

Structural equality has a comparison counterpart: IStructuralComparable. It determines if an array comes before or after or is equal to another array based on the elements within it.

Read more of this post

Filed under .NET, C# language features Tagged with ,

Thread safe queues in .NET

July 14, 2015 1 Comment

We saw how standard Queues work in .NET in this post. Queues are first-in-first-out collections where the first element added to the collection will the first to be removed. Queues are ideal to model consumer-producer scenarios where a producer adds items to a queue which are then processed by a consumer in the order they came in.

If you’d like to have a Queue that is shared among multiple threads in a multi-threaded application then the “normal” Queue of T object won’t be enough. You can never be sure of the current state of the queue in the very moment when a certain thread tries to dequeue an item from it. The queue may have been modified by another thread just a millisecond before and then the Dequeue method will fail. In general you should be very careful with how you share the resources among different threads.

Read more of this post

Filed under .NET, C# language features, Task Parallel Library Tagged with , , ,

Implementing equality for reference objects using IEquatable and the == operator: summary

July 8, 2015 Leave a comment

We have looked at implementing IEquatable and overriding various equality-related methods and operators in various other posts on this blog. You can look at this page and scroll down to the section called “Comparison and equality” to view all of them.

In this post we’ll put all of these together and implement a joined equality strategy for our reference type.

Read more of this post

Filed under .NET, C# language features Tagged with ,

Thread-safe stacks in .NET

July 7, 2015 3 Comments

We saw how Stacks work in .NET in this post. Stacks are last-in-first-out collections where the last element added to the collection will the first to be removed.

If you’d like to have a Stack that is shared among multiple threads in a multi-threaded application then the “normal” Stack of T object won’t be enough. You can never be sure of the current state of the stack in the very moment when a certain thread tries to pop an item from it. The stack may have been modified by another thread just a millisecond before and then the Pop method will fail. In general you should be very careful with how you share the resources among different threads.

Read more of this post

Filed under .NET, C# language features, Task Parallel Library Tagged with , , ,

FIFO collections with Queue of T in .NET C#

July 3, 2015 2 Comments

FIFO, that is first-in-first-out, collections are represented by the generic Queue of T class in .NET. Queues are collections where a new element is placed on top of the collection and is removed last when the items are retrieved.

Let’s say that you’re throwing a party where you follow a Queue policy as far as guests are concerned. As time goes by you’d like all of them to leave eventually and the first one to go will be the first person who has arrived. This is probably a most just policy than what we saw in the post on stack collections.

Read more of this post

Filed under .NET, C# language features, Generics Tagged with ,

How to check whether two HashSets are equal in C# .NET

July 1, 2015 Leave a comment

Two HashSet objects in C# are equal if they contain the same values regardless of their order in the collection.

Consider the following integer sets:

HashSet<int> intHashSetOne = new HashSet<int>()
{
	1,2,6,5,7,5
};

HashSet<int> intHashSetTwo = new HashSet<int>()
{
	2,2,8,5,9,4
};

HashSet<int> intHashSetThree = new HashSet<int>()
{
	6,7,5,5,2,1
};

Read more of this post

Filed under .NET, C# language features, Generics Tagged with , , ,

← Older posts

Newer posts →

Elliot Balynn's Blog

A directory of wonderful thoughts

Software Engineering

Web development

Disparate Opinions

Various tidbits

chsakell's Blog

WEB APPLICATION DEVELOPMENT TUTORIALS WITH OPEN-SOURCE PROJECTS

Once Upon a Camayoc

ARCHIVED: Bite-size insight on Cyber Security for the not too technical.