Basic Generic Repository Pattern and Unity of Work Frame Work in ASP.NET MVC3 : Part 1

}

Step 5:

Now We have to create our "studentController.cs" class under our "Controller" folder.

Please see the following step:



Choose appropriate template fields like shown in the Image above (marked with red).

After clicking the "ADD" button the "studentController.cs" class will be created and the corresponding "Razor view" page will also be generated with insert, update , delete, details and Index Pages.

It will look like the following picture:



Step 6:

In StudentController.cs, replace the code currently in the class with the following code:

public class StudentController : AsyncController
{
public IStudentRepository studentRepository;
StudentRepository StudentRepository = new StudentRepository(new SchoolContext());
private SchoolContext db = new SchoolContext();
public StudentController()
{
this.studentRepository = new StudentRepository(new SchoolContext());
}
public StudentController(IStudentRepository StudentRepository)
{
this.studentRepository = StudentRepository;
}

//private SchoolContext db = new SchoolContext();

//
// GET: /Student/
public ViewResult Index(string currentFilter, int? page)
{
if (Request.HttpMethod != "POST")
{
page = 1;
}
var students = from s in studentRepository.GetStudents()
select s;

int pageSize = 5;
int pageNumber = (page ?? 1);

// return View(students.ToList());
return View(students.ToPagedList(pageNumber, pageSize));
}
[HttpPost ]
public ActionResult Index(string sortOrder, string searchString, string currentFilter, int? page)
{
if (this.Request.IsAjaxRequest())
{
string filepath = this.Request.AppRelativeCurrentExecutionFilePath.ToString();
searchString = filepath.Split('/').LastOrDefault();
ViewBag.NameSortParm = String.IsNullOrEmpty(sortOrder) ? "Name desc" : "Name Asc";
ViewBag.DateSortParm = sortOrder == "Date" ? "Date desc" : "Date";
if (Request.HttpMethod == "POST")
{
if (currentFilter != null)
searchString = currentFilter;
}
else
{
//searchString = currentFilter;
page = 1;
}
ViewBag.CurrentFilter = searchString;
}

var students = from s in db.Students
select s;

switch (sortOrder)
{
case "Name desc":
students = students.OrderByDescending(s=>s.LastName );
break;
case "Name Asc":
students = students.OrderByDescending(s => s.FirstMidName);
break;
case "Date":
students = students.OrderBy(s => s.EnrollmentDate);
break;
case "Date desc":
students = students.OrderByDescending(s => s.EnrollmentDate);
break;
default:
students = students.OrderByDescending(s => s.FirstMidName);
break;
}
if (!String.IsNullOrEmpty(searchString))
{
students = students.Where(s => s.LastName.ToUpper().Contains(searchString.ToUpper())
|| s.FirstMidName.ToUpper().Contains(searchString.ToUpper()));
}
int pageSize = 1;
int pageNumber = (page ?? 1);

return View(students.ToPagedList(pageNumber, pageSize));
//return PartialView("_List", students.ToPagedList(pageNumber, pageSize));

}
/// <summary>
/// return value calling from autocomplete textbox
/// </summary>
/// <param name="term"></param>
/// <returns></returns>

public JsonResult AutocompleteSuggestions(string term)
{
var suggestions = from s in db.Students
select s.FirstMidName ;
var namelist = suggestions.Where(n => n.ToLower().StartsWith(term.ToLower()));
// return namelist.ToList();
return Json(namelist, JsonRequestBehavior.AllowGet);
}

//
// GET: /Student/Details/5

public ViewResult Details(int id)
{
//Student student = db.Students.Find(id);

Student student = StudentRepository.GetStudentbyId(id);
return View(student);

}

//
// GET: /Student/Create

public ActionResult Create()
{
return View();
}

//
// POST: /Student/Create

[HttpPost]
public ActionResult Create(Student student)
{
try
{
if (ModelState.IsValid)
{
StudentRepository.InsertStudent(student);
StudentRepository.Save();
return RedirectToAction("Index");
}
}
catch(DataException)
{
ModelState.AddModelError("","Eror while saving");
}

return View(student);
}

//
// GET: /Student/Edit/5

public ActionResult Edit(int id)
{
Student student = StudentRepository.GetStudentbyId(id);
return View(student);
}

//
// POST: /Student/Edit/5

[HttpPost]
public ActionResult Edit(Student student)
{
if (ModelState.IsValid)
{
StudentRepository.UpdateStudent(student);
StudentRepository.Save();
return RedirectToAction("Index");
}
return View(student);
}

//
// GET: /Student/Delete/5

public ActionResult Delete(int id, bool? saveChangesError)
{
if (saveChangesError.GetValueOrDefault())
{
ViewBag.ErrorMessage = "Unable to save changes. Try again, and if the problem persists see your system administrator.";
}
Student student = StudentRepository.GetStudentbyId(id);
return View(student);
}

//
// POST: /Student/Delete/5

[HttpPost, ActionName("Delete")]
public ActionResult DeleteConfirmed(int id)
{
try
{
//Student student = db.Students.Find(id);
//db.Students.Remove(student);
//db.SaveChanges();
////Student studentToDelete = new Student() { StudentID = id };
////db.Entry(studentToDelete).State = EntityState.Deleted;
//Student student = new Student() { StudentID = id };
//db.Entry(student).State = EntityState.Deleted;
//db.SaveChanges();
Student Stud = StudentRepository.GetStudentbyId(id);
StudentRepository.DeleteStudent(id);
StudentRepository.Save();

}
catch (DataException)
{
//Log the error (add a variable name after DataException)
return RedirectToAction("Delete",
new System.Web.Routing.RouteValueDictionary {
{ "id", id },
{ "saveChangesError", true } });
}
return RedirectToAction("Index");

}

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

The controller now declares a class variable for an object that implements the IStudentRepository interface instead of the context class:

private IStudentRepository studentRepository;

The default constructor creates a new context instance, and an optional constructor allows the caller to pass in a context instance.

public StudentController()
{
this.studentRepository = new StudentRepository(new SchoolContext());
}

public StudentController(IStudentRepository studentRepository)
{
this.studentRepository = studentRepository;
}

In the CRUD methods, the repository is now called instead of the context (normally we called in controller class):

var students = from s in studentRepository.GetStudents()
select s;
Student student = studentRepository.GetStudentByID(id);
studentRepository.InsertStudent(student);
studentRepository.Save();
studentRepository.UpdateStudent(student);
studentRepository.Save();
studentRepository.DeleteStudent(id);
studentRepository.Save();
And the Dispose method now disposes the repository instead of the context:

studentRepository.Dispose();

Now run the application.

In my next article I will show you what is unity of framework and how it is used in Generic Repository pattern.

Conclusion

So in this article we have learned what a repository pattern is in ASP.Net MVC3 and how to use it.