blazorwasmefcoreexample's Introduction

BlazorWasmEFCoreExample

Example of a Blazor WebAssembly project that uses Entity Framework Core on the server for data access.

Do you prefer Blazor Server instead? No problem! The same project is implemented for server here.

I created this series of blog posts to explain the project in detail (note: series is valid up to commit e6ac27b):

For the latest version, read about the latest round of refactoring here:

Build a Blazor WebAssembly LOB App Part 4: Make it Blazor-Friendly

Thank you

🙏 Thanks to John Barrett for helping identify initial issues.

Features

Application hosted authentication and registration
Extended identity features to audit user creation, modification, email confirmation, and deletion
Entity Framework Core
Multiple data contexts
Entity Framework Core logging
Shadow properties: the database tracks row version, the user who created the entity and timestamp, and the user who last modified the entity and timestamp, without having to define these properties on the C# domain class
Automatic audit that tracks changes with a before/after snapshot and is generated at the data context level
Optimistic concurrency with delta resolution (when the database changes, the UI shows the changes so the user can overwrite or abort)
Entity validation on the client and server using data annotations
A grid that features paging, sorting, and filtering with debounce (i.e. typing three characters will result in just one database round trip)
Dynamic filtering and sorting with serverside evaluation
99% of the UI is contained in a Razor class library that is usable from both Blazor WebAssembly and Blazor Server applications
Example of the repository pattern: the client and server use the same interface with a different implementation
Use of IHttpClientFactory to create a custom client with an authorization message handler

Quick start

Prerequisites

.NET Core SDK (3.1.300 or later)
Visual Studio Code, OR
Visual Studio 2019 16.6 or later

Code and Connection Strings

Optionally fork the repository.
Clone the repository (or your fork):

git clone https://github.com/jeremylikness/BlazorWasmEFCoreExample.git
If you don't have localdb installed, update appsettings.json and appsettings.Development.json in the ContactsApp.Server project to point to a valid database instance.
The DefaultConnection is used for identity and can have any database name.
The blazorcontactsdb is used for the application database and must match ContactContext.BlazorContactsDb in the ContactsApp.DataAccess project (the default value is blazorcontactsdb).

Visual Studio

Open the solution file.
Ensure the ContactsApp.Server project is set as the start up project.
Open the NuGet Package Manager -> Package Manager Console.
In the console, with the server project selected, create the identity migration by typing:

Add-Migration -Context ApplicationAuditDbContext Initial
After it is complete, apply the migration:

Update-Database -Context ApplicationAuditDbContext
You are ready to launch the application.

See note at the end of the next section.

Visual Studio Code

Navigate to the ContactsApp/Server folder.
If you haven't installed the EF Core Command Line Interface (CLI), install it by following these instructions. Choose the latest stable version (the project file currently ships with version 3.1.4).
Run

dotnet ef migrations add --context ApplicationAuditDbContext Initial

to set up the identity database migrations.
Run

dotnet ef database update --context ApplicationAuditDbContext

to create the identity database.
Type

dotnet run

to start the server. Navigate to the port specified.

Note: the demo app is designed to create and populate the contacts database the first time you open the web page. This may result in a delay of up to several minutes on first load. This is normal and is just used to make setup easier. Subsequent runs should load faster.

Migrations for Contacts Database

The context for contacts (ContactContext) resides in the ContactsApp.DataAccess assembly. It is a .NET Standard class library and cannot be executed directly. I created a ContactContextFactory in the ContactsApp.Server project to enable migrations by using the SQL Server provider and loading the connection string. To create a migration, you must specify the executable startup project and the context name. This command will create a migration in the Migrations folder named InitialContact (assuming this is run from the root of the solution directory):

dotnet ef migrations add --startup-project ContactsApp/Server --context ContactContext InitialContact

Use the --namespace parameter to specify a different namespace to help avoid conflicts with the identity context.

Submit any feedback, questions, suggestions, or issues here.

Regards,

@JeremyLikness

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blazorwasmefcoreexample's Issues

Question Why are u doing reposity pattern when EF core implements this

Hi just a query why are u doing the repository pattern in this example when ef core uses it as default?

Identity Schema does not get created

Following on from running the cmd with the --conext specifiied:

update-database -Context ApplicationAuditDbContext

(my identity db is 'JLContactsAppIdentityDb') the update does not seem to pick up the expected schema for any Identity objects.

update-database -Context ApplicationAuditDbContext
Build started...
Build succeeded.
Microsoft.EntityFrameworkCore.Database.Command[20101]
Executed DbCommand (331ms) [Parameters=[], CommandType='Text', CommandTimeout='60']
CREATE DATABASE [JLContactsAppIdentityDb];
Microsoft.EntityFrameworkCore.Database.Command[20101]
Executed DbCommand (75ms) [Parameters=[], CommandType='Text', CommandTimeout='60']
IF SERVERPROPERTY('EngineEdition') <> 5
BEGIN
ALTER DATABASE [JLContactsAppIdentityDb] SET READ_COMMITTED_SNAPSHOT ON;
END;
Microsoft.EntityFrameworkCore.Database.Command[20101]
Executed DbCommand (6ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
SELECT 1
Microsoft.EntityFrameworkCore.Database.Command[20101]
Executed DbCommand (12ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
CREATE TABLE [__EFMigrationsHistory] (
[MigrationId] nvarchar(150) NOT NULL,
[ProductVersion] nvarchar(32) NOT NULL,
CONSTRAINT [PK___EFMigrationsHistory] PRIMARY KEY ([MigrationId])
);
Microsoft.EntityFrameworkCore.Database.Command[20101]
Executed DbCommand (1ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
SELECT 1
Microsoft.EntityFrameworkCore.Database.Command[20101]
Executed DbCommand (13ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
SELECT OBJECT_ID(N'[__EFMigrationsHistory]');
Microsoft.EntityFrameworkCore.Database.Command[20101]
Executed DbCommand (2ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
SELECT [MigrationId], [ProductVersion]
FROM [__EFMigrationsHistory]
ORDER BY [MigrationId];
Done.
PM>

sdfgd

Question: Code First Migration using the database context 'ContactContext'

I been looking at approaches to carry out code first migrations using the Context for 'blazorcontactsdb' database (ContactContext). For example - adding a new property on the ContactsApp.Model.Contact class.

So the context obviously exists in a different assembly from ContactsApp.Server.

Is there some way of running a migration eg dotnet ef migrations add xxx -o Migrations with a switch so it can find the context in another project?

Cheers

Getting- 'More than on context found'

Should we be specifying a particular db context?

Contact Edit fails: 'Could not find contact with id 3'

View and Delete work as expected.

<p>Could not find contact with id @ContactId.</p> is the error message. That extra . looks like a problem but removing it changes nothing.

Did I break something after download?
Kal

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