Introduction
In .NET framework 4.5 asynchronous programming concept has been introduced. In this regard, .NET introduced two keyword async and await. It is much easier to implement than the multi-threading concept. The .NET Framework 4 introduced an asynchronous programming concept referred to as a Task and ASP.NET MVC 4 supports Task. In this article I will show you a simple CRUD operation using asynchronous programming by async, await and Task.

A simple overview on “async, await, Task” Keyword

async

• The async modifier indicates that the method, lambda expression, or anonymous method will work asynchronously.
• Method with async modifier also called async method.
• An async method provides a convenient way to do potentially long-running work without blocking the caller’s thread.
• The caller of an async method can resume its work without waiting for the async method to finish.
• Typically, a method modified by the async keyword contains at least one await expression or statement.

await

• Typically await keyword used to free a thread
• The await operator is applied to a task in an asynchronous method to suspend the execution of the method until the awaited task completes.
• The asynchronous method in which await is used must be modified by the async keyword. Such a method, defined by using the async modifier, and usually containing one or more await expressions, is referred to as an async method.
• The task to which the await operator is applied typically is the return value from a call to a method that

implements.

Task

• The main types are System.Threading.Tasks.Task
• Represents an asynchronous operation that can be waited on and cancelled
• System.Threading.Tasks.Task, which is a task that can return a value.

MSDN References:

• https://msdn.microsoft.com/en-us/library/hh156513(v=vs.110).aspx
• https://msdn.microsoft.com/en-us/library/hh156528(v=vs.110).aspx
• https://msdn.microsoft.com/en-us/library/system.threading.tasks(v=vs.110).aspx

Here I implement async modifier to a CRUD operation on Employee Object. Let’s start.
Tools and Technology used
I used following tools and technology to develop the project –

1. Visual Studio 2013
2. Visual C#
3. ASP.NET MVC 5
4. Entity Framework 6
5. Razor view engine

Step 1: Create an ASP.NET MVC 5 application using Visual Studio 2013. I kept the application name “MVCAsync”.
Help: How to create first application using asp.net MVC

Step 2: Configure connection string in web.config

Step 3: Create a model in model folder – Employee

Employee

   public class Employee
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string NickName { get; set; }
        public string Designation { get; set; }
        public string Dept { get; set; }
    }

Step 4: Create a DbContext name EmployeeDBContext in Model folder.

    public class EmployeeDBContext : DbContext
    {
        public EmployeeDBContext()
            : base("DefaultConnection")
        {
        }

        public DbSet Employees { get; set; }
    }

Step 5: Create a controller name – EmployeeController. Select template “MVC5 Controller with views, using entity framework”. EmployeeController will create in Controller folder and related views will be created in Views/Employee folder. At the time of creating controller – mark use async controller action.

Step 6: Employee Controller is given below. A simple difference over normal method is –

• used async keyword in Action Method.
• Used Task instead of typical ActionResult
• And used await keyword in any operation.

   public class EmployeeController : Controller
    {
        private EmployeeDBContext db = new EmployeeDBContext();

        // GET: /Employee/
        public async Task Index()
        {
            return View(await db.Employees.ToListAsync());
        }

        // GET: /Employee/Details/5
        public async Task Details(int? id)
        {
            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            Employee employee = await db.Employees.FindAsync(id);
            if (employee == null)
            {
                return HttpNotFound();
            }
            return View(employee);
        }

        // GET: /Employee/Create
        public ActionResult Create()
        {
            return View();
        }

        // POST: /Employee/Create
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for 
        // more details see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task Create([Bind(Include="Id,Name,NickName,Designation,Dept")] Employee employee)
        {
            if (ModelState.IsValid)
            {
                db.Employees.Add(employee);
                await db.SaveChangesAsync();
                return RedirectToAction("Index");
            }

            return View(employee);
        }

        // GET: /Employee/Edit/5
        public async Task Edit(int? id)
        {
            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            Employee employee = await db.Employees.FindAsync(id);
            if (employee == null)
            {
                return HttpNotFound();
            }
            return View(employee);
        }

        // POST: /Employee/Edit/5
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for 
        // more details see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task Edit([Bind(Include="Id,Name,NickName,Designation,Dept")] Employee employee)
        {
            if (ModelState.IsValid)
            {
                db.Entry(employee).State = EntityState.Modified;
                await db.SaveChangesAsync();
                return RedirectToAction("Index");
            }
            return View(employee);
        }

        // GET: /Employee/Delete/5
        public async Task Delete(int? id)
        {
            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            Employee employee = await db.Employees.FindAsync(id);
            if (employee == null)
            {
                return HttpNotFound();
            }
            return View(employee);
        }

        // POST: /Employee/Delete/5
        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public async Task DeleteConfirmed(int id)
        {
            Employee employee = await db.Employees.FindAsync(id);
            db.Employees.Remove(employee);
            await db.SaveChangesAsync();
            return RedirectToAction("Index");
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                db.Dispose();
            }
            base.Dispose(disposing);
        }
    }

Step 7: Views – After selecting and executing template views are automatically created. Here is the views for CRUD operation of Employee.

Create.cshtml

@model MVCAsync.Models.Employee





    
    


    @Scripts.Render("~/bundles/jquery")
    @Scripts.Render("~/bundles/jqueryval")
    
    
    @using (Html.BeginForm()) 
    {
        @Html.AntiForgeryToken()
        
        

            
Employee
            

            @Html.ValidationSummary(true)
    
            

                @Html.LabelFor(model => model.Name, new { @class = "control-label col-md-2" })
                

                    @Html.EditorFor(model => model.Name)
                    @Html.ValidationMessageFor(model => model.Name)
                
            
    
            

                @Html.LabelFor(model => model.NickName, new { @class = "control-label col-md-2" })
                

                    @Html.EditorFor(model => model.NickName)
                    @Html.ValidationMessageFor(model => model.NickName)
                
            
    
            

                @Html.LabelFor(model => model.Designation, new { @class = "control-label col-md-2" })
                

                    @Html.EditorFor(model => model.Designation)
                    @Html.ValidationMessageFor(model => model.Designation)
                
            
    
            

                @Html.LabelFor(model => model.Dept, new { @class = "control-label col-md-2" })
                

                    @Html.EditorFor(model => model.Dept)
                    @Html.ValidationMessageFor(model => model.Dept)
                
            
    
            

                

                    
                
            
        
    }
    
    

        @Html.ActionLink("Back to List", "Index")
    

Delete.cshtml

@model MVCAsync.Models.Employee






    
    


    
Are you sure you want to delete this?
    

        
Employee
        

        

            

                @Html.DisplayNameFor(model => model.Name)
            
    
            

                @Html.DisplayFor(model => model.Name)
            
    
            

                @Html.DisplayNameFor(model => model.NickName)
            
    
            

                @Html.DisplayFor(model => model.NickName)
            
    
            

                @Html.DisplayNameFor(model => model.Designation)
            
    
            

                @Html.DisplayFor(model => model.Designation)
            
    
            

                @Html.DisplayNameFor(model => model.Dept)
            
    
            

                @Html.DisplayFor(model => model.Dept)
            
    
        
    
        @using (Html.BeginForm()) {
            @Html.AntiForgeryToken()
    
            

                 |
                @Html.ActionLink("Back to List", "Index")
            
        }
    

Details.cshtml

@model MVCAsync.Models.Employee





    
    


    

        
Employee
    	

        

            

                @Html.DisplayNameFor(model => model.Name)
            
    
            

                @Html.DisplayFor(model => model.Name)
            
    
            

                @Html.DisplayNameFor(model => model.NickName)
            
    
            

                @Html.DisplayFor(model => model.NickName)
            
    
            

                @Html.DisplayNameFor(model => model.Designation)
            
    
            

                @Html.DisplayFor(model => model.Designation)
            
    
            

                @Html.DisplayNameFor(model => model.Dept)
            
    
            

                @Html.DisplayFor(model => model.Dept)
            
    
        
    
    

        @Html.ActionLink("Edit", "Edit", new { id = Model.Id }) |
        @Html.ActionLink("Back to List", "Index")
    

Edit.cshtml

@model MVCAsync.Models.Employee






    
    


    @Scripts.Render("~/bundles/jquery")
    @Scripts.Render("~/bundles/jqueryval")
    
    
    @using (Html.BeginForm())
    {
        @Html.AntiForgeryToken()
        
        

            
Employee
            

            @Html.ValidationSummary(true)
            @Html.HiddenFor(model => model.Id)
    
            

                @Html.LabelFor(model => model.Name, new { @class = "control-label col-md-2" })
                

                    @Html.EditorFor(model => model.Name)
                    @Html.ValidationMessageFor(model => model.Name)
                
            
    
            

                @Html.LabelFor(model => model.NickName, new { @class = "control-label col-md-2" })
                

                    @Html.EditorFor(model => model.NickName)
                    @Html.ValidationMessageFor(model => model.NickName)
                
            
    
            

                @Html.LabelFor(model => model.Designation, new { @class = "control-label col-md-2" })
                

                    @Html.EditorFor(model => model.Designation)
                    @Html.ValidationMessageFor(model => model.Designation)
                
            
    
            

                @Html.LabelFor(model => model.Dept, new { @class = "control-label col-md-2" })
                

                    @Html.EditorFor(model => model.Dept)
                    @Html.ValidationMessageFor(model => model.Dept)
                
            
    
            

                

                    
                
            
        
    }
    
    

        @Html.ActionLink("Back to List", "Index")
    

Index.cshtml

@model IEnumerable





    
    


    

        @Html.ActionLink("Create New", "Create")
    
    
    
    @foreach (var item in Model) {
        
    }
    
    

        

            

                @Html.DisplayNameFor(model => model.Name)
            
            

                @Html.DisplayNameFor(model => model.NickName)
            
            

                @Html.DisplayNameFor(model => model.Designation)
            
            

                @Html.DisplayNameFor(model => model.Dept)
            
            

        

            

                @Html.DisplayFor(modelItem => item.Name)
            
            

                @Html.DisplayFor(modelItem => item.NickName)
            
            

                @Html.DisplayFor(modelItem => item.Designation)
            
            

                @Html.DisplayFor(modelItem => item.Dept)
            
            

                @Html.ActionLink("Edit", "Edit", new { id=item.Id }) |
                @Html.ActionLink("Details", "Details", new { id=item.Id }) |
                @Html.ActionLink("Delete", "Delete", new { id=item.Id })
            
        

Step 8: Add a link to _Layout page to access Employee information in Views/Shared

    		

                    
@Html.ActionLink("Home", "Index", "Home")
                    
@Html.ActionLink("About", "About", "Home")
                    
@Html.ActionLink("Contact", "Contact", "Home")
                    
@Html.ActionLink("Employee", "Index", "Employee")
                

Step 9: Run the following command in package manager console one after another

PM> Enable-Migrations -ContextTypeName EmployeeDBContext
PM> Add-Migration created
PM> Update-Database –Verbose

Now run application and apply CRUD operation on it. It’s simple!!

Output: