Once enabled, depending on the type of project you have created you’ll have the following global using statements added to your project implicitly.
| SDK | Default namespaces |
|---|---|
| Microsoft.NET.Sdk | |
| System | |
| System.Collections.Generic | |
| System.IO | |
| System.Linq | |
| System.Net.Http | |
| System.Threading | |
| System.Threading.Tasks | |
| Microsoft.NET.Sdk.Web | |
| System.Net.Http.Json | |
| Microsoft.AspNetCore.Builder | |
| Microsoft.AspNetCore.Hosting | |
| Microsoft.AspNetCore.Http | |
| Microsoft.AspNetCore.Routing | |
| Microsoft.Extensions.Configuration | |
| Microsoft.Extensions.DependencyInjection | |
| Microsoft.Extensions.Hosting | |
| Microsoft.Extensions.Logging | |
| Microsoft.NET.Sdk.Worker | |
| Microsoft.Extensions.Configuration | |
| Microsoft.Extensions.DependencyInjection | |
| Microsoft.Extensions.Hosting | |
| Microsoft.Extensions.Logging |
Although this might sound like a good idea, there are downsides. It turns out
that with multiple targets enabled (frameworks versions mainly) some of the
included namespaces (like System.Net.Http) do not exist in your project unless
a NuGet package is added.
But more importantly, it obscures the dependencies of your project. In addition, reducing using statements in your project can be easily achieved by defining namespaces globally in a file.
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>net8.0</TargetFramework>
<ImplicitUsings>enable</ImplicitUsings>
</PropertyGroup>
</Project>
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>net8.0</TargetFramework>
</PropertyGroup>
</Project>
global using System;
global using System.Collections.Generic;
global using System.IO;
global using System.Linq;
global using System.Net.Http;
global using System.Threading;
global using System.Threading.Tasks;