The “Cannot access a disposed object” exception in ASP.NET Core, especially when using Entity Framework’s DbContext, is a common issue developers face. This article explores the root causes, prevention strategies, and best practices to avoid this error in modern ASP.NET Core applications.
The ObjectDisposedException typically occurs when an attempt is made to use an object that has already been disposed. In the context of ASP.NET Core and Entity Framework, this often involves the DbContext. The error message generally looks like this:
Continue reading “Cannot access a disposed object in ASP.NET Core when injecting DbContext”System.ObjectDisposedException: Cannot access a disposed object.
This post explaines how to add index to EF Core with extra columns included from code.
When creating indexes with code first migrations in Entity Framework Core you can create an index on a table by adding the following to your DbContext:
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<table>()
.HasIndex(t => new { t.Column1, t.Column2}); }
Continue reading “Add Index with Include Entity Framework Core”
Lately we had a discussion on when to use ConfigureAwait(true) or ConfigureAwait(false) in ASP.NET Core 2. In the end most of the team, including me, had a faulty assumption on how to do this in ASP.NET Core. In this case ASP.NET Core is different from ASP.NET. Good to know if you have to decide on what to use in ASP.NET core.
Continue reading “ASP.NET Core correct usage of ConfigureAwait with async/await”
In a scenario where we were using SQL server as a queue, before publishing events to external queues, we wanted the data to be processed only once and in order, even with multiple processors for failover. When reading from the table we wanted to lock the records and block other processors from reading those records, while being processed. This is called Pessimistic Concurrency, unfortunately Entity Framework Core does not support this out of the box. To realize Pessimistic Concurrency you need to write your own SQL queries directly on the database (The solution is database type bound, in this case Microsoft SQL server). This blog post will show how it can be accomplished.
Continue reading “Implement Pessimistic Concurrency in Entity Framework Core”
In .NET 6 and 8, gracefully handling application shutdown is crucial for releasing resources or completing ongoing tasks before the application ends. The IApplicationLifetime interface was deprecated in favor of IHostApplicationLifetime in ASP.NET Core 3.0, and this approach continues in .NET 6/8.
In modern ASP.NET Core applications, IHostApplicationLifetime is injected into services, such as controllers or services where you need to handle shutdown events.
Create a VSTS release pipeline for Azure Functions
Azure Functions enable you to easily run small pieces of code in the cloud. To do this right, you need to setup continuous delivery of the infrastructure and the code involved. Otherwise you will end with an uncontrolled environment where nobody knows what code is actually running. In this blog post I’ll describe how to setup a deployment pipeline for Functions with VSTS. This will enable you to deploy Functions as Infrastructure as Code.
From an deployment perspective an Azure Function contains of two parts:
Both the ARM template and the code can be deployed from VSTS. By doing this, you can manage functions like any other Azure resource.
Continue reading “Use VSTS to deploy Functions as Infrastructure as Code”
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