Razor Pages:
Razor Page is a simplified web application model. On comparing with the 'MVC' template, razor pages won't have 'Controller', which means Razor Page is a combination of 'View' and 'Model'. Routing itself is configured within the page or view. A Razor Page mostly contains 2 files like '*.cshtml'(View) and '*.cshtml.cs'(model).
Create A .NET6 Razor Pages Application:
Let's create a .Net6 Razor Page sample application to accomplish our demo. We can use either Visual Studio 2022 or Visual Studio Code(using .NET CLI commands) to create any.Net6 application. For this demo, I'm using the 'Visual Studio Code'(using the .NET CLI command) editor.
CLI command
dotnet new webapp -o Your_Project_Name
dotnet new webapp -o Your_Project_Name
Let's explore the project to understand its structure:
(1) Let's understand the initial services registered in 'Program.cs'.
- Here 'AddRazorPages' service is registered.
(2) Le's understand the initial middleware configured in 'Program.cs'.
- The 'UseExceptionHandler()' loads a generic exception page for the production environment.
- The 'UseHsts()' adds the Strict-Transport-Security header.
- The 'UseHttpsRedirection', HTTP request redirect to HTTPS.
- The 'UseStaticFiles', load static files like CSS, JS, Images, etc.
- The 'UseRouting' middleware is where the routing decisions are made.
- The 'UseAuthorization()' protect against unauthorized or unauthenticated users.
- The 'MapRazorPages()' enables endpoint routing for the Razor Pages.
SQL Query To Create A Sample Table:
Run the below command to create a sample table.
CREATE TABLE [dbo].[Cake] (
[Id] INT IDENTITY (1, 1) NOT NULL,
[Name] VARCHAR (MAX) NULL,
[Price] DECIMAL (18, 2) NULL,
[Description] VARCHAR (MAX) NULL
);
Entity Framework Core:
Entity Framework Core is an Object/Relational Mapping(ORM) framework. EF Core makes database communication more fluent and easy. The 'DatabaseContext' class acts as a database from our c# code, it will contain all registered tables as 'DbSet<TEntity>'(TEntity is any POCO class of a table).
In this demo, we are going to implement the 'Code With Existing Database' technique. Creating the classes for an existing database is known as 'Code First With Existing Database'.
Install Entity Framework Core NuGet:
Now install the Entity Framework Core NuGet.
Package Manager Command:
Install-Package Microsoft.EntityFrameworkCore -Version 6.0.1
Install-Package Microsoft.EntityFrameworkCore -Version 6.0.1
Package Manager Command:
dotnet add package Microsoft.EntityFrameworkCore --version 6.0.1
dotnet add package Microsoft.EntityFrameworkCore --version 6.0.1
Now install SQLServer that is Entity Framework Core dependant library.
Package Manager Command:
Install-Package Microsoft.EntityFrameworkCore.SqlServer -Version 6.0.1
Install-Package Microsoft.EntityFrameworkCore.SqlServer -Version 6.0.1
Package Manager Command:
dotnet add package Microsoft.EntityFrameworkCore.SqlServer --version 6.0.1
dotnet add package Microsoft.EntityFrameworkCore.SqlServer --version 6.0.1
Setup Entity Framework Core DatabaseContext:
Let's create a class that represents our table. So let's create a folder like 'Data' and a subfolder like 'Entities' and then add a class like 'Cake.cs'.
Data/Entities/Cake.cs:
namespace Dot6.Razor.Crud.Demo.Data.Entities;
public class Cake
{
public int Id { get; set; }
public string Name { get; set; }
public decimal Price { get; set; }
public string Description { get; set; }
}
To manage or control all the table classes we have to create DatabaseContext class. So let's create our context class like 'MyWorldDbContext.cs' in the 'Data' folder.Data/MyWorldDbContext.cs:
using Dot6.Razor.Crud.Demo.Data.Entities;
using Microsoft.EntityFrameworkCore;
namespace Dot6.Razor.Crud.Demo.Data;
public class MyWorldDbContext : DbContext
{
public MyWorldDbContext(DbContextOptions<MyWorldDbContext> options) : base(options)
{
}
public DbSet<Cake> Cake { get; set; }
}
- (Line: 6) The 'Microsoft.EntityFrameworkCore.DbContext' needs to be inherited by our 'MyWorldDbContext' to act as a Database context class.
- (Line: 8) The 'Microsoft.EntityFrameworkCore.DbContextOptions' is instance of options that we are going to register in 'Program.cs' like 'ConnectionString', 'DatabaseProvider', etc.
- (Line: 12) All our table classes must be registered inside of our Database context class with 'DbSet<T>' so that the entity framework core can communicate with the tables of the database.
In 'appsettings.Development.json' add your database connection string.
appsettings.Development.json:
"ConnectionStrings":{
"MyWorldDbConnection":"your_connection"
}
Register the Database Context service in the 'Program.cs' file for dependency injection.Program.cs:
builder.Services.AddDbContext<MyWorldDbContext>(options =>
{
options.UseSqlServer(builder.Configuration.GetConnectionString("MyWorldDbConnection"));
});
Read Operation:
In 'Pages' folder create a new folder like 'Cakes', inside of it let's Razor Page for our read operation like 'Index.csthml'(View file), 'Index.cshtml.cs'(Model file).
Pages/Cakes/Index.cshtml.cs:
using Dot6.Razor.Crud.Demo.Data;
using Dot6.Razor.Crud.Demo.Data.Entities;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.EntityFrameworkCore;
namespace Dot6.Razor.Crud.Demo.Pages.Cakes;
public class IndexModel : PageModel
{
private readonly MyWorldDbContext _myWorldDbContext;
public IndexModel(MyWorldDbContext myWorldDbContext)
{
_myWorldDbContext = myWorldDbContext;
}
public List<Cake> AllCakes = new List<Cake>();
public async Task<IActionResult> OnGetAsync()
{
AllCakes = await _myWorldDbContext.Cake.ToListAsync();
return Page();
}
}
- (Line: 8) To make our c# class as Razor Page model it needs to inherit the 'Microsoft.AspNetCore.Mvc.RazorPages.PageModel'.
- (Line: 11) Injecting Database context into our Razor Page model.
- (Line: 16) Declared a variable of a type that is collection 'Cake' to hold the data from the database and then bind the data to the UI.
- (Line: 18-22) The default method executed for the razor page HTTP Get request is 'OnGet' or 'OnGetAsync'. It is always ideal to have one method for each HTTP verbs like 'GET', 'POST'. There is an option to customize the name of the HTTP GET request method then it should be like 'OnGet{YourCustomName}' or 'OnGet{YourCustomName}Async', but if we customize the method name then we have to specify the custom name as value to the query parameter 'handler'. So don't give the custom name unless it is required. Inside of Our 'OnGetAsync' method we have implemented our logic to fetch the data from the database.
@page "/cake/home"
@using Dot6.Razor.Crud.Demo.Data.Entities
@model Dot6.Razor.Crud.Demo.Pages.Cakes.IndexModel
<div class="container">
<div class="row">
@foreach (var item in Model.AllCakes)
{
<div class="col-md-3 m-3">
<div class="card" style="width: 18rem;">
<div class="card-body">
<h5 class="card-title">@item.Name</h5>
<h6 class="card-subtitle mb-2 text-muted">@item.Price $</h6>
<p class="card-text">@item.Description</p>
</div>
</div>
</div>
}
</div>
</div>
- (Line: 1) Using the '@page' directive we can define route to our Razor Page.
- (Line: 3) Define the model which is the class name of the 'Index.cshtml.cs' file.
- (Line: 7-18) Loop the data to bind to UI.
Create Operation:
In the 'Pages/Cakes' folder add a new razor page for our create operation like 'Create.cshtml'(View file), 'Create.cshtml.cs'(Model file).
Let's create a view model for storing the form data(For storing form data if we use 'Cake.cs' table entity it will work but there may be changes of overposting data so to avoid it, recommend using View Model ). So let's create folder 'Vms' inside of it add 'CakeVm.cs'.
Vms/CakeVm.cs:
namespace Dot6.Razor.Crud.Demo.Vms;
public class CakeVm
{
public int Id { get; set; }
public string Name { get; set; }
public decimal Price { get; set; }
public string Description { get; set; }
}
Pages/Cakes/Create.cshtml.cs:
using Dot6.Razor.Crud.Demo.Data;
using Dot6.Razor.Crud.Demo.Data.Entities;
using Dot6.Razor.Crud.Demo.Vms;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
namespace Dot6.Razor.Crud.Demo.Pages.Cakes;
public class CreateModel : PageModel
{
private readonly MyWorldDbContext _myWorldDbContext;
public CreateModel(MyWorldDbContext myWorldDbContext)
{
_myWorldDbContext = myWorldDbContext;
}
[BindProperty]
public CakeVm CakeVm { get; set; }
public IActionResult OnGet()
{
return Page();
}
public async Task<IActionResult> OnPostAsync()
{
var entry = _myWorldDbContext.Add(new Cake());
entry.CurrentValues.SetValues(CakeVm);
await _myWorldDbContext.SaveChangesAsync();
return Redirect("home");
}
}
- (Line: 17) The 'CakeVm' will be used to store the form data. By decorating the property with the 'BindProperty' attribute we are enhancing capability like storing the form data onto it directly without any explicit mapping.
- (Line: 18-21) The 'OnGet()' method loads the create a form to us.
- (Line: 23-29) The 'OnPostAsync' method gets invoked for the post request.
- (Line: 25) Attaching the empty 'Cake' instance to Database Context, now that state is 'Added' means read to save to database.
- (Line: 26) Updating the value of 'Cake' instance which is added to Database Context at Line:25. So this approach we no need to map the properties explicitly between the 'Cake' and 'CakeVm' objects.
- (Line: 27)Saving changes to the database by calling the 'SaveChangeAsync()' method.
- (Line: 28) Redirecting back to the '/cake/home' page.
@page "/cake/create"
@model Dot6.Razor.Crud.Demo.Pages.Cakes.CreateModel
<div class="container">
<div class="row ">
<div class="col-md-6 offset-md-3">
<form method="POST">
<legend>Create A New Cake</legend>
<div class="mb-3">
<label for="txtName" class="form-label">Name</label>
<input asp-for="CakeVm.Name" type="text" class="form-control" id="txtName" />
</div>
<div class="mb-3">
<label for="txtCost" class="form-label">Cost</label>
<input asp-for="CakeVm.Price" type="text" class="form-control" id="txtCost" />
</div>
<div class="mb-3">
<label for="txtDescription" class="form-label">Cost</label>
<textarea asp-for="CakeVm.Description" type="text" class="form-control"
id="txtDescription"></textarea>
</div>
<button type="submit" class="btn btn-primary">Submit</button>
</form>
</div>
</div>
</div>
- (Line: 1) Defined Razor Page route.
- (Line: 2) Register the Model.
- (Line: 4-28) Rendering a form to create a new record. Here each input HTML field is bound with our object that is 'CakeVm' with help of the 'asp-for' tag helper. So any data entered to the form and on submitting the form then the form data values directly stored into the 'CakeVm'(because it is decorated with 'BindProperty' attribute).
Pages/Cakes/Index.cshtml:
<!-- Code hidden for display purspose -->
<div class="container">
<div class="row">
<div class="col-md-4 offset-md-4">
<a asp-page="./create" class="btn btn-primary">Create New Cake</a>
</div>
</div>
<div class="row">
@foreach (var item in Model.AllCakes)
{
}
</div>
</div>
step1:
Update Operation:
In the 'Pages/Cakes' add a new Razor Page for update operation like 'Edit.cshtml.cs'(Model file), 'Edit.cshtml'(View file).
Pages/Cakes/Edit.cshtml.cs:
using Dot6.Razor.Crud.Demo.Data;
using Dot6.Razor.Crud.Demo.Data.Entities;
using Dot6.Razor.Crud.Demo.Vms;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.EntityFrameworkCore;
namespace Dot6.Razor.Crud.Demo.Pages.Cakes;
public class EditModel : PageModel
{
private MyWorldDbContext _myWorldDbContext;
public EditModel(MyWorldDbContext myWorldDbContext)
{
_myWorldDbContext = myWorldDbContext;
}
[BindProperty]
public CakeVm? CakeVm { get; set; }
public async Task<IActionResult> OnGetAsync(int id)
{
CakeVm = await _myWorldDbContext.Cake
.Where(_ => _.Id == id)
.Select(_ =>
new CakeVm
{
Description = _.Description,
Id = _.Id,
Name = _.Name,
Price = _.Price
}).FirstOrDefaultAsync();
if (CakeVm == null)
{
return NotFound();
}
return Page();
}
public async Task<IActionResult> OnPostAsync(int id)
{
var cakeToUpdate = await _myWorldDbContext.Cake.FindAsync(id);
if (cakeToUpdate == null)
{
return NotFound();
}
if (await TryUpdateModelAsync<Cake>(
cakeToUpdate,
"CakeVm",
c => c.Name, c => c.Description, c => c.Price
))
{
await _myWorldDbContext.SaveChangesAsync();
return Redirect("home");
}
return Page();
}
}
- (Line: 18-19) The 'CakeVm' property captures form data on page post, which is possible because of attributes 'BindProperty'.
- (Line: 21-39) The 'OnGetAsync()' to load the form with data that needs to be updated.
- (Line: 23-32) Fetch the record by 'id'(query parameter) and assign the data to our 'CakeVm' property.
- (Line: 41-61) The 'OnPostAsync()' gets invoked for the Post request.
- (Line: 43) Fetch the data from the database that needs to be updated.
- (Line: 50-58) The 'TryUpdateModelAsync()' method helps to copy the data from the 'CakeVm' to 'cakeToUpdate'(variable of type Cake). Only specified props will be copied to the destination object. On invoking the 'SaveChangesAsyn()' updates the data to the database.
@page "/cake/edit"
@model Dot6.Razor.Crud.Demo.Pages.Cakes.EditModel
<div class="container">
<div class="row ">
<div class="col-md-6 offset-md-3">
<form method="POST">
<legend>Update A New Cake</legend>
<div class="mb-3">
<label for="txtName" class="form-label">Name</label>
<input asp-for="CakeVm.Name" type="text" class="form-control" id="txtName" />
</div>
<div class="mb-3">
<label for="txtCost" class="form-label">Cost</label>
<input asp-for="CakeVm.Price" type="text" class="form-control" id="txtCost" />
</div>
<div class="mb-3">
<label for="txtDescription" class="form-label">Cost</label>
<textarea asp-for="CakeVm.Description" type="text" class="form-control"
id="txtDescription"></textarea>
</div>
<button type="submit" class="btn btn-primary">Submit</button>
</form>
</div>
</div>
</div>
- (Line: 1) Defined route for our Razor Page.
- (Line: 2) Defined the Model for our Razor Page.
- (Line: 4-28) Render the edit form. Each field binding is enabled by the 'asp-for' razor tag.
Pages/Cakes/Index.cshtml:
<!-- code hidden for display purpose --> <div class="card" style="width: 18rem;"> <div class="card-body"> <h5 class="card-title">@item.Name</h5> <h6 class="card-subtitle mb-2 text-muted">@item.Price $</h6> <p class="card-text">@item.Description</p> <a asp-page="./edit" asp-route-id="@item.Id" class="btn btn-primary">Edit</a> </div> </div>
- (Line: 7) Added anchor tag as 'Edit' button, the route defined at 'asp-page' helper tag, and then query parameter defined at 'asp-route-id' tag helper.
Delete Operation:
In the 'Pages/Cakes' folder add a new Razor Page for delete operation like 'Delete.cshtml'(Model file), 'Delete.cshtml.cs'(View file).
Pages/Cakes/Delete.cshtml.cs:
using Dot6.Razor.Crud.Demo.Data;
using Dot6.Razor.Crud.Demo.Vms;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.EntityFrameworkCore;
namespace Dot6.Razor.Crud.Demo.Pages.Cakes;
public class DeleteModel : PageModel
{
private readonly MyWorldDbContext _myWorldDbContext;
public DeleteModel(MyWorldDbContext myWorldDbContext)
{
_myWorldDbContext = myWorldDbContext;
}
public string ErrorMessage { get; set; }
public CakeVm? CakeVm { get; set; }
public async Task<IActionResult> OnGetAsync(int id, bool? saveChangesError)
{
CakeVm = await _myWorldDbContext.Cake
.Where(_ => _.Id == id)
.Select(_ =>
new CakeVm
{
Description = _.Description,
Id = _.Id,
Name = _.Name,
Price = _.Price
}).FirstOrDefaultAsync();
if (CakeVm == null)
{
return NotFound();
}
if (saveChangesError ?? false)
{
ErrorMessage = $"Error to delete the record id - {id}";
}
return Page();
}
public async Task<IActionResult> OnPostAsync(int id)
{
var recordToDelete = await _myWorldDbContext.Cake.FindAsync(id);
if (recordToDelete == null)
{
return Page();
}
try
{
_myWorldDbContext.Cake.Remove(recordToDelete);
await _myWorldDbContext.SaveChangesAsync();
return Redirect("./home");
}
catch
{
return Redirect($"./delete?id={id}&saveChangesError=true");
}
}
}
- (Line: 17) The 'ErrorMessage' property display the delete error message.
- (Line: 18) The 'CakVm' displays the data on the delete confirmation page.
- (Line: 19-41) The 'OnGetAsync' method to loads the data to display for the delete confirmation page.
- (Line: 20-31) Load the record to delete from the database by 'id'.
- (Line: 36-39) Based on the 'saveChangesError' boolean value populating the error message. One thing to remember is 'true' value will be assigned to 'saveChangeError' only from the 'OnPostAsync' method when an error occurs on deleting the record.
- (Line: 43-62) The 'OnPostAsync' method gets invoked on confirm delete post request.
- (Line: 45) Fetching the record from the database by 'id'.
- (Line: 54-55) Deleting the record from the database.
- (Line: 56) After successful delete navigating back to the home page.
- (Line: 60) An error occurs on deleting the record then we will redirect to the same 'Delete' page by assigning the 'saveCahgesError' query parameter value 'true' for displaying the error message.
Pages/Cakes/Delete.cshtml:
Now in 'index.cshtml' add the 'Delete' button.@page "/delete"
@model Dot6.Razor.Crud.Demo.Pages.Cakes.DeleteModel
<div class="container">
<div class="row">
<p class="text-danger">@Model.ErrorMessage</p>
</div>
<div class="row">
<div class="col-md-3 m-3">
<legend>Confirm To Delete</legend>
<div class="card" style="width: 18rem;">
<div class="card-body">
<h5 class="card-title">@Model.CakeVm.Name</h5>
<h6 class="card-subtitle mb-2 text-muted">@Model.CakeVm.Price $</h6>
<p class="card-text">@Model.CakeVm.Description</p>
<div>
<form method="post">
<button type="submit" class="btn btn-danger">Confirm Delete</button>
</form>
</div>
</div>
</div>
</div>
</div>
</div>
Pages/Cakes/Index.cshtml:
<a asp-page="./delete" asp-route-id="@item.Id" class="btn btn-danger">Delete</a>
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Wrapping Up:
Hopefully, I think this article delivered some useful information on .NET6 Razor Pages CRUD Operation. using I love to have your feedback, suggestions, and better techniques in the comment section below.
Thanks you very much, for so nice and clear presentation, Best ever seen in Web or youtube. This eases my brain headages.
ReplyDeleteThanks. This was as clear and helpful as it can be.
ReplyDeleteNic
ReplyDeleteWow, Most clear. thank you , i have build it,
ReplyDeleteNice Explanation
ReplyDelete