Tag: EFcore

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Fixing “No database provider has been configured for this DbContext” in Entity Framework Core

I’m using Entity Framework in most of the projects that I’m working on – and for the most part, it’s a pleasure to work with. But as always, there are plenty of chances to run into issues – so obviously, I stumble into all of the rare stuff that IS broken! This one I hadn’t really seen before – “No database provider has been configured for this DbContext”. This time I encountered the issue while setting up a new project and getting started working on…Continue reading Fixing “No database provider has been configured for this DbContext” in Entity Framework Core

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“An assembly specified in the application dependencies manifest was not found” when running Add-Migration in Entity Framework Core?

Another quick one – I’m sure this doesn’t apply to all cases, but I’m still logging it in case someone (like myself) stumbles upon the issue and finds help here. I was building a solution with some Azure Functions fetching and populating data in a database, and was planning on building a UI for browsing the data at some point later on – but I actually got stuck on the second step already :) While adding the database to my project, and running Add-Migration in…Continue reading “An assembly specified in the application dependencies manifest was not found” when running Add-Migration in Entity Framework Core?

T-SQL, yes please!

How to verify connection to database in Entity Framework Core?

This article explains how to perform a very simple and lightweight database connection test for an existing database context. A while ago, I needed to develop a simple API that I can poll from a load balancer to see whether: An Azure service hosting it is up and It has a connection to its SQL database This simple API would be used for monitoring purposes – simple stuff, sure, but what’s the best way to implement this without causing any unnecessary load to the database,…Continue reading How to verify connection to database in Entity Framework Core?

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How to resolve persistent “Build started… Build failed.” when trying to run Entity Framework Core commands?

This time, I’m happy to present you perhaps the simplest way of fixing an annoying and persistent issue with a misleading error message! Wait, does that sound familiar? It’s almost like that’s what half of my articles are about… Anyway, I was happily going my way about creating a couple of new fields to an entity and then scaffolding my changes to a new migration using Entity Framework Core’s Add-Migration, but this happened: Build started… Build failed. “Oh”, I thought. “I must have messed something…Continue reading How to resolve persistent “Build started… Build failed.” when trying to run Entity Framework Core commands?

WHAT IN TARNATION EF CORE?

How to resolve another “An error occurred while updating the entries” exception in Entity Framework Core

This article offers yet another possible fix to an issue, where trying to call SaveChanges() in Entity Framework Core throws a pretty generic “An error occurred while updating the entries”-exception, and you’re left wondering what in tarnation is wrong this time. And admittedly, that’s a really generic error, so it could be pretty much whatever. But in this article, I’ll go through one possibility – hopefully it helps! Problem So I was just pushing in some new rows to an incredibly simple table in my…Continue reading How to resolve another “An error occurred while updating the entries” exception in Entity Framework Core

One does not simply use just one DbContext with multiple ConnectionStrings in Entity Framework Core.

How to implement multiple Connection Strings for one DbContext in EF Core?

Recently, while building an app service to host a .NET Core API, I had to implement the logic for using both Read-Only and Read-Write Database Contexts for Entity Framework Core. In this particular case, it was the same database – just different contexts, because depending on the location of the app service the app was deployed in, read and write operations might actually go to different database instances, That’s really easy, right? Well… Yes and no. Essentially, it’s easy to spin up, but comes with…Continue reading How to implement multiple Connection Strings for one DbContext in EF Core?

C# & .NET

How to get the EF Core Connection String?

This article describes how to access and extract the connection strings from your Entity Framework (Core) database context objects. This is quite convenient if you need to display or log the connection string used for your current DbContext for some reason – or if you somehow form your DbContext objects dynamically, and need to verify which connection string you’re using. I’m sure there are other use cases, too. You probably have an interesting one, if you landed on this page! Problem A while ago, I…Continue reading How to get the EF Core Connection String?

.NET Core fundamentals in one picture.

How to add creator/modified info to all of your EF models at once in .NET Core

This is a tip that should often be the first thing you do in your projects with database backend, no matter which technology you use: Add some basic info about modified and created times, and the user information – so that if something happens, everyone will know who to blame 😉 There’s a lot of great blog articles describing how to do this in .NET Framework, but not that many for .NET Core. It’s very similar, but not the same. I learned that by copy-pasting…Continue reading How to add creator/modified info to all of your EF models at once in .NET Core

Azure Functions CLI - such a pretty logo for such an awesome functionality

How to access Entity Framework Core’s DbContext in an Azure Function?

This post describes how you can access your Entity Framework Core model classes and the database context in your Azure Functions. In my example I’m using EF Core 2.1, but the main principle should be the same for later versions as well. Please note, that I use Azure functions runtime v2 (but it should work the same in v3 !) Another easy one, that I was unable to find much guidance on! But first, let’s start with the basics. Why would you want to have…Continue reading How to access Entity Framework Core’s DbContext in an Azure Function?

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Current User in ASP.NET Core

This post describes how to get the currently logged in user using ASP.NET Core. This is compared with how it’s done in ASP.NET Framework. Background In ASP.NET Core (and .NET Core in general), a lot of things are done a bit differently than what you might be used to if you’re coming from the .NET Framework world. That’s what I’ve been learning building more and more stuff with it, instead of good old .NET Framework. The learning curve is definitely there, but it’s not that…Continue reading Current User in ASP.NET Core