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Hire Freelance C# Developers and Engineers

Rory Woods

Freelance C# Developer

Rory is a software consultant delivering solutions to fill enterprise needs. He brings technical skill and experience guiding teams in not just how to build..., but what to build. He has extensive experience on the Microsoft web stack, including ASP.NET MVC, Web API, SQL Server, and Azure. 

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Dan Napierski

Freelance C# Developer

Dan is a software architect and technology professional focusing on applications of blockchain technologies. He has years of experience providing profession...al consulting services to clients ranging from startups to global corporations. He specializes in bringing rigorous testing and bulletproof code to tough engineering challenges. He has deep expertise in many aspects of artificial intelligence, blockchain, machine learning, and automation. 

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Cheryl Hoskins

Freelance C# Developer

Cheryl is a developer with strong communication skills who seeks to provide software solutions that delight her clients. She has enjoyed working with React,... Node.js, REST APIs, GraphQL, SQL, MongoDB, and JavaScript recently and is ready to start putting her skills to work for you. In addition to her technical background, Cheryl has an MBA and can translate your business requirements into quality software solutions. 

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Nick Ivanov

Freelance C# Developer

Nick is a senior software developer who's spent more than a decade working with .NET, SQL, C#, JavaScript, HTML, and CSS. He is the type of developer who ca...n flesh out the front-end and also build a solid back-end. He's worked with databases—with SQL mostly but also is experienced with PostgreSQL, MongoDB, Oracle, and Sybase. Nick can explain his work process clearly and concisely and is eager to start his career doing freelance remote work.  

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Mukesh Agrawal

Freelance C# Developer

Mukesh has more than 12 years of software development and design experience (mostly with Microsoft technology stack), and a proven ability to develop effici...ent, scalable and fault-tolerant solutions to complex problems. He has extensive experience with all phases of the software development cycle. 

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Charles Cook, Ph.D.

Freelance C# Developer

Charles has a Ph.D. in aerospace engineering and spent three years developing custom data processing and analysis programs for NASA. He specializes in scala...ble, enterprise-level application development and engineering solutions for exceptionally high throughputs. He is also the founder and owner of GreatVocab.com, for which he developed the core system using novel concepts in data analysis and control theory. 

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Tao Zhang

Freelance C# Developer

Tao is a software engineer who has been working in a large-scale (14+ million line of code) real-time acquisition software projects for more than 11 years,... mainly on the back end. He is especially good at C++/C#, Python programming, performance optimization, TDD, and debugging. 

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Dmitry Pavlov

Freelance C# Developer

Dmitry is a senior .NET and C# developer with over fifteen years of experience in creating web applications. He has received the Microsoft MVP (Visual C#) A...ward seven times since 2008 and is a capable team leader. Dmitry has also received master of science degrees in computer science and in structural geology and modeling. Clients call him "The Coding Machine." 

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Scott Hankinson

Freelance C# Developer

Scott has produced technology used by companies like Microsoft and S&P Global. He has developed software integral for companies selling to larger entities,... as well as in taking companies public via IPO. Scott has the ability to design, develop, and deliver database solutions into a production environment. He is capable of controlling every aspect of a software development team as an architect, developer, and project leader. 

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Rizwan Rizvi

Freelance C# Developer

Rizwan has a reputation for overcoming complex challenges through clear thinking, innovative approaches, and enhancing the communication between different p...arts of organizations. Throughout his career, he has optimized the efforts of diverse and dispersed teams of IT professionals and consistently has delivered projects profitably in challenging environments. 

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3
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FAQs

  • How are Toptal C# developers different?

    At Toptal, we thoroughly screen our C# developers to ensure we only supply experts of the highest caliber. Of the more than 100,000 people who apply to join the Toptal network each year, we accept fewer than 3%. You'll work with engineering experts (never generalized recruiters or HR reps) to understand your goals, technical needs, and team dynamics. The end result: expertly-matched talent from our network, hand-selected to fit your business needs.

  • What is the no-risk trial period for C# developers?

    We make sure that each engagement between you and your C# developer begins with a trial period of up to two weeks. This means that you have time to confirm the engagement will be successful. If you're completely satisfied with the results, we'll bill you for the time and continue the engagement for as long as you'd like. If you're not completely satisfied, you won't be billed. From there, we can either part ways, or we can provide you with another expert who may be a better fit and with whom we will begin a second, no-risk trial.

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    Depending on availability and how fast you can progress, you could start your no-risk trial with a C# developer within 48 hours of signing up. Most of our engagements start within 2 weeks of discussing your project with us.

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Guide to Hiring a great C# Developer

C# came in as a new kid on the block. At first it was ignored, then it was ridiculed, and then it was fought against, but now it continues to win over developers all over the world. The direct result of this growth is a large number of developers that are using C#. This guide covers topics that every C# developer needs to have mastered, and is essential when making your next hire.

How to Hire a Great C# Developer

Remember the Y2K bug? Apparently, the world was supposed to end due to havoc in computer networks all over the planet. Just one year before that, we heard announcements that 1999 will mark the end of the world because it had an inverted 666 in its name. In such turbulent times, when many were piling food in their basements, hoping that Armageddon would not find them, there were a few visionaries that were still inventing some cool stuff. One of them is Anders Hejlsberg, who gathered a team of Microsoft developers and created Cool, which was the first version of new C-like Object Oriented Language, later to be named C#.

14 years and 5 versions later, C# is one of the most popular languages in the industry. Despite the fact that James Gosling and Bill Joy stated that C# was just an imitation of Java, while some other critics even called C# a boring repetition that lacks innovation, C# is now standing tall next to all the other platforms used by millions of developers all over the world.

C# is a multi-paradigm programming language encompassing strong typing, as well as imperative, declarative, functional, generic, object-oriented (class-based), and component-oriented programming disciplines. You can use it to build any type of application, whether it is a service, console, desktop, web or even smartphone application.

Each application type requires a specific set of skills on top of standard C# syntax, and finding a great C# developer is not an easy task. If you are looking for a web developer you should expect knowledge of the HTTP protocol, Web Forms, MVC Framework and Razor View Engine, while some other application will have its own challenges.

This article should help you identify a developer that understands C# in its core. Regardless on the application type, techniques and tips mentioned below should be universal to all C# developers and they should all be able to demonstrate extensive understanding of these topics.

I’ll try to cover general topics that every developer must be aware of. The purpose of this article is to point to several specific topics. Evaluating knowledge of each of them in depth would require much more than one or two questions.

Generics

Generics were one of the earliest features of the C# language. Generics make it possible to design classes and methods that defer the specification of one or more types until the class or method is declared and instantiated by client code.

Q: Consider the following code, which is part of a console application:

static void Main(string[] args)
{
  DeveloperList listOfDevelopers = new DeveloperList();
  IntegerList listOfNumbers = new IntegerList();
  
  listOfNumbers.DoSomething(5);
  listOfDevelopers.DoSomething(new Developer());
}

public class Developer
{
  public string Name { get; set; }
  public List<string> Skills { get; set; }
}

public class DeveloperList
{
  public void DoSomething(Developer developer)
  {
    Console.WriteLine("Doing something with developer");
  }
}

public class IntegerList
{
  public void DoSomething(Int32 number)
  {
    Console.WriteLine("Doing something with number");
  }
}

Optimize the code in a way to replace DeveloperList and IntegerList with one class named GenericList that will contain single doSomething method. Make sure to handle the case when GenericList is instantiated by an unexpected type.

The solution should be similar to this:

static void Main(string[] args)
{
  GenericList<int> listOfNumbers = new GenericList<int>();
  GenericList<Developer> listOfDevelopers = new GenericList<Developer>();
  GenericList<string> listOfStrings = new GenericList<string>();
  
  listOfNumbers.DoSomething(5);
  listOfDevelopers.DoSomething(new Developer());
  listOfStrings.DoSomething("Whats up");
}

public class Developer
{
  public string Name { get; set; }
  public List<string> Skills { get; set; }
}

class GenericList<T>
{
  public void DoSomething(T value){
  if (value.GetType() == typeof(Int32))
      {
          Console.WriteLine("Doing something with ");
            return;
        }

        if (value.GetType() == typeof(Developer))
        {
            Console.WriteLine("Doing something with developer");
            return;
        }

        Console.WriteLine("I cannot do anything with " + value.GetType().ToString());
  }
}

LINQ

LINQ (Language-Integrated Query) is one of the coolest features in C#. It was introduced in Visual Studio 2008 and it provides extremely powerful query capabilities to C#. LINQ introduces standard patterns for querying and updating data supporting any kind of data store.

Or, in simple words, LINQ enables SQL-like queries against collections of objects in C#.

Q: Assuming that you have a Class Developer defined like this:

class Developer
{
  public string Name { get; set; }
  public List<string> Skills { get; set; }
}

Write a code that would extract all developers that have the “SQL” skill, from a List<Developer> developers.

The answer that you would expect from a developer that understands LINQ would be similar to this:

var results = from d in developers where d.Skills.Contains("SQL") select d;

Developers that are not used to LINQ would probably use standard iteration methods using for, foreach or while combined with if. Similar to this:

var results = new List<Developer>();
foreach (var d in developers)
{
  if (d.Skills.Contains("SQL"))
  results.Add(d);
}

Even though this is a technically correct solution, it would be less desirable due to the complexity of the code.

Lambda Expressions

Lambda expressions are methods that do not require declaration. These are function that are implemented “in-line” with the rest of the code. Lambda expressions are particularly helpful for writing LINQ query expressions.

To create a lambda expression, you specify input parameters (if any) on the left side of the lambda operator =>, and you put the expression or statement block on the other side. For example, the lambda expression x => x * x specifies a parameter named x and returns the value of x squared.

The general definition of lambda expression is:

(parameters) => Code

Q: Complete the following code by implementing the methods Square and Double based on the Calculate delegate and lambda expressions.

delegate int Calculate(int input);
static void Main(string[] args)
{
  int value1 = Square(5);
  int value2 = Double(5);
  
  Console.WriteLine(value1);
  Console.WriteLine(value2);
  
  Console.ReadLine();
}

The expected solution should be as simple as adding two lines of code:

delegate int Calculate(int input);
static void Main(string[] args)
{
  Calculate Square = x => x * x;  // NEW
  Calculate Double = x => x * 2;  // NEW
  
  int value1 = Square(5);
  int value2 = Double(5);
  
  Console.WriteLine(value1);
  Console.WriteLine(value2);
  
  Console.ReadLine();
}

The Calculate delegate is declared to return Int and accept one Int as a parameter, so Square and Double methods just implemented the proper calculations.

Named Arguments

Named arguments free you from the need to remember or to look up the order of parameters in the parameter lists of called methods. The parameter for each argument can be specified by parameter name.

Consider the following code:

static void Main(string[] args)
{
  Console.WriteLine(Power(4, 3)); //64
  Console.WriteLine(Power(3, 4)); //81
}

static double Power(double baseNumber, double power)
{
  return Math.Pow(baseNumber, power);
}

Changing the order of parameters passed to the Power method would produce a different result; 64 one way, versus 81 the other.

Q: Update the code above to produce same result (4 to power of 3 = 64) regardless of the order of parameters passed to the Power method.

The solution for this problem is to pass named parameters. You would have to change the way you call Power.

Console.WriteLine(Power(baseNumber: 4, power: 3)); //64
Console.WriteLine(Power(power: 3, baseNumber: 4)); //64

The only thing you needed to do is add an argument name when passing in the values.

Optional Parameters

The definition of a method, constructor, indexer, or delegate can specify that its parameters are required or that they are optional. Any call must provide arguments for all required parameters, but can omit arguments for optional parameters.

Each optional parameter has a default value as part of its definition. If no argument is sent for that parameter, the default value is used. Optional parameters are defined at the end of the parameter list, after any required parameters. If the caller provides an argument for any one of a succession of optional parameters, it must provide arguments for all preceding optional parameters. Comma-separated gaps in the argument list are not supported.

Q: Extend the Developer class with a boolean property named Enabled and a constructor that will accept name and the optional enabled value.

public class Developer
{
  public string Name { get; set; }
  public List<string> Skills { get; set; }
}

The expected solution would be:

public class Developer
{
  public Developer(string name, bool enabled=true)
  {
    Name = name;
    Enabled = enabled;
  }
  public string Name { get; set; }
  public bool Enabled { get; set; }
  public List<string> Skills { get; set; }
}

Use of the optional enabled parameter is shown in the following example:

Developer elvis = new Developer("Elvis");       //elvis.Enabled = true
Developer mick = new Developer("Mick", false);  //mick.Enabled = false

Asynchronous Processing

Asynchrony is essential for activities that are potentially blocking, such as when your application accesses network resources. Access to a network resource sometimes is slow or delayed. If such an activity is blocking a synchronous process, the entire application must wait. In an asynchronous process, the application can continue with other work that doesn’t depend on the network resource until the potentially blocking task finishes.

Visual Studio 2012 introduced a simplified approach, async programming, that leverages asynchronous support in the .NET Framework 4.5 and the Windows Runtime. The compiler does the difficult work that the developer used to do, and your application retains a logical structure that resembles synchronous code. As a result, you get all the advantages of asynchronous programming with a fraction of the effort.

The async and await keywords in C# are the heart of async programming. By using those two keywords, you can use resources in the .NET Framework or the Windows Runtime to create an asynchronous method almost as easily as you create a synchronous method. Asynchronous methods that you define by using async and await are referred to as async methods.

The following example shows an async method.

async Task<int> AccessTheWebAsync()
{
  HttpClient client = new HttpClient();
  Task<string> getStringTask = client.GetStringAsync("https://www.toptal.com");
  DoIndependentWork();
  string urlContents = await getStringTask;
  return urlContents.Length;
}

Q: What would be the output of the following code? Explain your answer.

static string statement = "Start";

static async Task<string> SayAwaited()
{
  await Task.Delay(5000);
  statement = "Awaited";
  Console.WriteLine(statement);
  return statement;
}

static async Task<string> SayDelayed()
{
  Thread.Sleep(1000);
  statement = "Delayed";
  Console.WriteLine(statement);
  return statement;
}

static void Main(string[] args)
{
  SayAwaited();
  SayDelayed();
  Console.WriteLine("Final: " + statement);
  Console.ReadLine();
}

After five seconds of the application being paused, the output of this code would be:

Delayed
Final: Delayed
Awaited

Note: The first “Delayed” will show up after a delay of one second.

The reason for this is in the way async methods are handled in C#, and the difference between Task.Delay and Thread.Sleep. The SayAwaited method will execute like any other method until it reaches the await command. At this point, C# will start another thread for executing Task.Delay on the new thread, while releasing current thread to proceed with next action, which is SayDelayed. After putting the main thread to sleep for one second, SayDelayed will set the value for the statement and execution will proceed with the remaining commands, WriteLine and ReadLine. While this is all happening, SayAwaited will be nicely paused in its own thread, and after 5 seconds it will set statement to “Awaited”, produce its own output, and return.

Q: Would there be any difference if statement = "Awaited" would be execute before await command? Explain your answer.

static async Task<string> SayAwaited()
{
  statement = "Awaited";
  await Task.Delay(5000);
  Console.WriteLine(statement);
  return statement;
}

In this case, the output would be the following:

Delayed
Final: Delayed
Delayed

The reason for this is that the “Awaited” value is assigned to statement before the await command is called. By the time Console.WriteLine(statement); in SayAwaited is executed, the value of statement has already been updated by the SayDelayed method.

Stay Sharp!

C# came in as a new kid on the block. At first it was ignored, then it was ridiculed, then it was fought against. Now it continues to win over developers all over the world. The direct result of this growth is the large number of developers that are using C#.

This article referenced topics that every C# developer should master. Make sure to cover these topic when you are looking for a great C# developer, and you will be one step closer to identifying the best of the best.

Top C# Developers are in high demand.

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