@{
Layout =
"~/Views/Shared/_Layout.cshtml";
}
TheViews\_ViewStart.cshtml file defines the common layout that all views will use,
therefore you can comment out or remove that code above
You
can use the Layout property to set a different layout view, or set it to null so no layout file will
be used.
2.
Controller – View
let's first talk about passing information
from the controller to a view. Controller classes are invoked in response to an
incoming URL request. A controller class is where you write the code that
handles the incoming browser requests, retrieves data from a database, and
ultimately decides what type of response to send back to the browser. View
templates can then be used from a controller to generate and format an HTML
response to the browser.
Controllers are responsible for providing
whatever data or objects are required in order for a view template to render a
response to the browser. A best practice: A view template should never
perform business logic or interact with a database directly. Instead, a view template should work only with the data that's
provided to it by the controller. Maintaining this "separation of
concerns" helps keep your code clean, testable and more maintainable.
3.
Remove unused Using
Note: Several unused
using statements have been removed. You can do this by right clicking
in the file, click Organize Usings,
and then click Remove Unused Usings.
4.
Default DB of Entity Framework
Entity Framework will default to using LocalDB
LocalDB is a lightweight version of the SQL Server Express Database
Engine that starts on demand and runs in user mode. LocalDB runs in a
special execution mode of SQL Server Express that enables you to work
with databases as .mdf files. Typically, LocalDB database
files are kept in the App_Data folder of a web project.
The name of the connection string must match the name of the DbContext class.
connectionString="..."
providerName="System.Data.SqlClient" />
using System;
using System.Data.Entity;
namespace MvcMovie.Models
{
public class Movie
{
public int ID { get; set; }
public string Title { get; set; }
public DateTime ReleaseDate { get; set; }
public string Genre { get; set; }
public decimal Price { get; set; }
}
public class MovieDBContext : DbContext
{
public DbSet<Movie> Movies { get; set; }
}
}
The ValidateAntiForgeryToken attribute is used to prevent forgery of a request and is paired
up with
@Html.AntiForgeryToken() in the edit view file (Views\Movies\Edit.cshtml),[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit([Bind(Include="ID,Title,ReleaseDate,Genre,Price")] Movie movie)
{
}
@model MvcMovie.Models.Movie
@{
ViewBag.Title = "Edit";
}
Edit
@using (Html.BeginForm())
{
@Html.AntiForgeryToken()
class="form-horizontal">
...
6.
Bind
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit([Bind(Include="ID,Title,ReleaseDate,Genre,Price")] Movie movie)
{
if (ModelState.IsValid)
{
db.Entry(movie).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
return View(movie);
}
The ASP.NET MVC model binder takes the posted form values and creates a
Movie object that's passed as the movie parameter. The ModelState.IsValid method verifies that the data submitted in the form can be used
to modify (edit or update) a Movie object.
7.
Html.BeginForm()
@using (Html.BeginForm("Index","Movies",FormMethod.Get))
8.
ViewBag & @Html.DropDownList
@Html.DropDownList("movieGenre", "All")
The parameter "movieGenre" provides the key for the
DropDownList helper to find a IEnumerable<SelectListItem> in the ViewBagvar GenreLst = new List();
var GenreQry = from d in db.Movies
orderby d.Genre
select d.Genre;
GenreLst.AddRange(GenreQry.Distinct());
ViewBag.movieGenre = new SelectList(GenreLst);
9.
Add new field to model (Code first)
If
the updated Movie model class in the application is now
different than the schema of the Movie table of the
existing database. (There's no Rating column in the
database table.)
There are a few
approaches to resolving the error:
1.
Have the Entity
Framework automatically drop and re-create the database based on the new model
class schema. This approach is very convenient early in the development cycle
when you are doing active development on a test database; it allows you to
quickly evolve the model and database schema together. The downside, though, is
that you lose existing data in the database — so you don't want to use this approach on a production
database! Using an initializer to automatically seed a database with test data
is often a productive way to develope an application. For more information on
Entity Framework database initializers, see Tom Dykstra's fantastic ASP.NET
MVC/Entity Framework tutorial.
2.
Explicitly modify the
schema of the existing database so that it matches the model classes. The
advantage of this approach is that you keep your data. You can make this change
either manually or by creating a database change script.
3.
Use Code First
Migrations to update the database schema. (Build -> add-migration Rating -> Build -> update-database)
10. [RegularExpression(@"^[A-Z]+[a-zA-Z'\s-]*$")]
In the code above, must
use only letters (white space, numbers and special characters are not
allowed
11. Install Entity Framework
From the Tools menu click NuGet Package Manager and then click Package Manager Console.
In the Package
Manager Console window
enter the following command:
Install-Package EntityFramework
12. relationship
between Student and Enrollment entities
public class Student
{
public int ID { get; set; }
public string LastName { get; set; }
public string FirstMidName { get; set; }
public DateTime EnrollmentDate { get; set; }
public virtual ICollection<Enrollment> Enrollments { get; set; }
}
public class Enrollment
{
public int EnrollmentID { get; set; }
public int CourseID { get; set; }
public int StudentID { get; set; }
public Grade? Grade { get; set; }
public virtual Course Course { get; set; }
public virtual Student Student { get; set; }
}
Entity properties
that are named
ID or classnameID are recognized as primary key properties.
A property is
interpreted as a foreign key property if it's named
13. Install
the PagedList.MVC NuGet Package
In the Package Manager Console window, make sure ghe Package source is nuget.org and the Default project is ContosoUniversity, and
then enter the following command:
Install-Package PagedList.Mvc
14. interception and Log SQL excute
15.
SQL Query in LinQ
string query = "SELECT * FROM Department WHERE DepartmentID =
@p0";
Department department = await db.Departments.SqlQuery(query, id).SingleOrDefaultAsync();
string query = "SELECT EnrollmentDate,
COUNT(*) AS StudentCount "
+ "FROM Person "
+ "WHERE Discriminator = 'Student' "
+ "GROUP BY EnrollmentDate";
IEnumerable<EnrollmentDateGroup> data = db.Database.SqlQuery<EnrollmentDateGroup>(query);
ViewBag.RowsAffected
= db.Database.ExecuteSqlCommand("UPDATE Course SET Credits = Credits * {0}", multiplier);
16. Examining
SQL sent to the database
IQueryable<Course> courses =
db.Courses
.Where(c => !SelectedDepartment.HasValue || c.DepartmentID ==
departmentID)
.OrderBy(d => d.CourseID)
.Include(d => d.Department);
var sql = courses.ToString();
17. Fix
error Newtonsoft.Json
“Could not load file or assembly
'Newtonsoft.Json, Version=6.0.0.0, Culture=neutral,
PublicKeyToken=30ad4fe6b2a6aeed' or one of its dependencies. The located
assembly's manifest definition does not match the assembly reference.
(Exception from HRESULT: 0x80131040)”
1.
Install
newest newtonsoft.json
2.
Run command
uninstall-package newtonsoft.json -force
install-package newtonsoft.json
3.
Add
below code to Web.config
<dependentAssembly>
<assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" />
<assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" />
<bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="8.0.0.0" />
</dependentAssembly>
</dependentAssembly>
4.
Copy
file from Referrence Propertices to bin folder
18. Asynchronous
- await Task.WhenAll
public async Task<ActionResult> PWGasync()
{
ViewBag.SyncType = "Asynchronous";
var widgetService = new WidgetService();
var prodService = new ProductService();
var gizmoService = new GizmoService();
var widgetTask = widgetService.GetWidgetsAsync();
var prodTask = prodService.GetProductsAsync();
var gizmoTask = gizmoService.GetGizmosAsync();
await Task.WhenAll(widgetTask, prodTask, gizmoTask);
var pwgVM = new ProdGizWidgetVM(
widgetTask.Result,
prodTask.Result,
gizmoTask.Result
);
return View("PWG", pwgVM);
}
19. ??
Operator
// Set y to the value of x if x is NOT null; otherwise,
// if x = null, set y to -1.
int y = x ?? -1;
20. Timestamp
for handle conflict Concurrency
public class Department
{
public int DepartmentID { get; set; }
[StringLength(50, MinimumLength = 3)]
public string Name { get; set; }
.......
[Timestamp]
public byte[] RowVersion { get; set; }
.......
public virtual ICollection<Course> Courses { get; set; }
}
The Timestamp attribute specifies that this column will be included in the
Where clause of Update and Delete commands sent to the database
21. [Authorize]
The Authorize filter checks to see if the user is authenticated. If the user
is not authenticated, it returns HTTP status code 401 (Unauthorized) without
invoking the action. You can apply the filter globally, at the controller
level, or at the level of individual actions.
22. the
string that you want to display contains a backslash character (\) or double
quotation marks ( " )
If
the string that you want to display contains a backslash character (\) or
double quotation marks (
" ), use a verbatim
string literal that's
prefixed with the @ operator. (In C#, the \ character has
special meaning unless you use a verbatim string literal.)@{ var myFilePath = @"C:\MyFolder\"; }
The path is: @myFilePath
To embed double quotation
marks, use a verbatim string literal and repeat the quotation marks:
@{ var myQuote = @"The person said: ""Hello, today is Monday."""; }
@myQuote
Here's the result of using
both of these examples in a page:
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