Asynchronous operations using Tasks (async, await)

Author: breno.dev

SalesWebMvc/Controllers/SellersController.cs

@@ -22,44 +22,44 @@ public SellersController(SellerService sellerService, DepartmentService departme
             _departmentService = departmentService;
         }
 
-        public IActionResult Index()
+        public async Task<IActionResult> Index()
         {
-            var list = _sellerService.FindAll();
+            var list = await _sellerService.FindAllAsync();
             return View(list);
         }
 
-        public IActionResult Create()
+        public async Task<IActionResult> Create()
         {
-            var departments = _departmentService.FindAll();
+            var departments = await _departmentService.FindAllAsync();
             var viewModel = new SellerFormViewModel { Departments = departments };
             return View(viewModel);
         }
 
 
         [HttpPost]
         [ValidateAntiForgeryToken]
-        public IActionResult Create(Seller seller)
+        public async Task <IActionResult> Create(Seller seller)
         {
             if (!ModelState.IsValid)
             {
-                var departments = _departmentService.FindAll();
+                var departments = await _departmentService.FindAllAsync();
                 var viewModel = new SellerFormViewModel { Seller = seller, Departments = departments };
                 return View(seller);
             }
 
 
-            _sellerService.Insert(seller);
+            await _sellerService.InsertAsync(seller);
             return RedirectToAction(nameof(Index));
         }
 
-        public IActionResult Delete(int? id)
+        public async Task<IActionResult> Delete(int? id)
         {
             if ( id == null)
             {
                 return RedirectToAction(nameof(Error), new { message = "Id not provided"});
             }
 
-            var obj = _sellerService.FindById(id.Value);
+            var obj = await _sellerService.FindByIdAsync(id.Value);
             if (obj == null)
             {
                 return RedirectToAction(nameof(Error), new { message = "Id not found" });
@@ -70,52 +70,52 @@ public IActionResult Delete(int? id)
 
         [HttpPost]
         [AutoValidateAntiforgeryToken]
-        public IActionResult Delete(int id)
+        public async Task <IActionResult> Delete(int id)
         {
-            _sellerService.Remove(id);
+           await _sellerService.RemoveAsync(id);
             return RedirectToAction(nameof(Index));
         }
 
-        public IActionResult Details(int? id)
+        public async Task <IActionResult> Details(int? id)
         {
             if (id == null)
             {
                 return RedirectToAction(nameof(Error), new { message = "Id not provided" });
             }
 
-            var obj = _sellerService.FindById(id.Value);
+            var obj = await _sellerService.FindByIdAsync(id.Value);
             if (obj == null)
             {
                 return RedirectToAction(nameof(Error), new { message = "Id not found" });
             }
             return View(obj);
         }
 
-        public IActionResult Edit(int? id)
+        public async Task <IActionResult> Edit(int? id)
         {
             if (id == null)
             {
                 return RedirectToAction(nameof(Error), new { message = "Id not provided" });
             }
 
-            var obj = _sellerService.FindById(id.Value);
+            var obj = await _sellerService.FindByIdAsync(id.Value);
             if (obj == null)
             {
                 return RedirectToAction(nameof(Error), new { message = "Id not found" });
             }
 
-            List<Department> departments = _departmentService.FindAll();
+            List<Department> departments = await _departmentService.FindAllAsync();
             SellerFormViewModel viewModel = new SellerFormViewModel { Seller = obj, Departments = departments };
             return View(viewModel);
         }
 
         [HttpPost]
         [ValidateAntiForgeryToken]
-        public IActionResult Edit(int id, Seller seller)
+        public async Task <IActionResult> Edit(int id, Seller seller)
         {
             if (!ModelState.IsValid)
             {
-                var departments = _departmentService.FindAll();
+                var departments = await _departmentService.FindAllAsync();
                 var viewModel = new SellerFormViewModel { Seller = seller, Departments = departments };
                 return View(seller);
             }
@@ -127,7 +127,7 @@ public IActionResult Edit(int id, Seller seller)
 
             try
             {
-                _sellerService.Update(seller);
+               await _sellerService.UpdateAsync(seller);
                 return RedirectToAction(nameof(Index));
             }
             catch(NotFoundException e)

SalesWebMvc/Services/DepartmentService.cs

@@ -3,6 +3,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
+using Microsoft.EntityFrameworkCore;
 
 namespace SalesWebMvc.Services
 {
@@ -15,9 +16,9 @@ public DepartmentService(SalesWebMvcContext context)
             _context = context;
         }
 
-        public List<Department> FindAll()
+        public async Task<List<Department>> FindAllAsync()
         {
-            return _context.Department.OrderBy(x => x.Name).ToList();
+            return await _context.Department.OrderBy(x => x.Name).ToListAsync();
         }
     }
 }

SalesWebMvc/Services/SellerService.cs

@@ -17,40 +17,42 @@ public SellerService(SalesWebMvcContext context)
             _context = context;
         }
 
-        public List<Seller> FindAll()
+        public async Task<List<Seller>> FindAllAsync()
         {
-            return _context.Seller.ToList();
+            return await _context.Seller.ToListAsync();
         }
 
-        public void Insert(Seller obj)
+        public async Task InsertAsync(Seller obj)
         {
             _context.Add(obj);
-            _context.SaveChanges();
+            await _context.SaveChangesAsync();
         }
 
-        public Seller FindById(int id)
+        public async Task<Seller> FindByIdAsync(int id)
         {
-            return _context.Seller.Include(obj => obj.Department).FirstOrDefault(obj => obj.Id == id);
+            return await _context.Seller.Include(obj => obj.Department).FirstOrDefaultAsync(obj => obj.Id == id);
         }
 
-        public void Remove(int id)
+        public async Task RemoveAsync(int id)
         {
-            var obj = _context.Seller.Find(id);
+            var obj = await _context.Seller.FindAsync(id);
             _context.Seller.Remove(obj);
-            _context.SaveChanges();
+            await _context.SaveChangesAsync();
         }
 
-        public void Update(Seller obj)
+        public async Task UpdateAsync(Seller obj)
         {
-            if (!_context.Seller.Any(x => x.Id == obj.Id))
+            bool hasAny = await _context.Seller.AnyAsync(x => x.Id == obj.Id);
+
+            if (!hasAny)
             {
                 throw new NotFoundException("Id not found");
             }
             try
             {
 
                 _context.Update(obj);
-                _context.SaveChanges();
+                await _context.SaveChangesAsync();
             }
             catch (DbUpdateConcurrencyException e)
             {