Convert to Global Using refactoring

note

Global using directive is a C# 10.0 feature.

By default, JetBrains Rider automatically detects C# version based on the associated compiler. However, you can specify the target C# version explicitly for a project — press AltEnter on the project in the Solution Explorer and use the Language version selector on the Application page of the Project Properties dialog .

To set the C# version for all projects in your solution, specify it in a Directory.Build.props file in your solution directory as described here.

This refactoring allows you to convert one or more local using directives into global using directives and move them to a new or existing file.

In the example below, we apply this refactoring to using System.Collections; in file One.cs. JetBrains Rider analyzes all files in the current project, finds the same using in Two.cs, and moves both of them to GlobalUsings.cs.

// One.cs
using System.Collections;
 
class One
{
    void Test(ArrayList list)
    {
        // do something
    }
}
 
// Two.cs
using System.Collections;
using System.Xml;
 
class Two
{
    void Test(ArrayList list,
                XmlReader reader)
    {
        // do something
    }
}
 
// GlobalUsings.cs
global using System.Linq;
global using System.Threading.Tasks;

// One.cs
class One
{
    void Test(ArrayList list)
    {
        // do something
    }
}
 
// Two.cs
using System.Xml;
 
class Two
{
    void Test(ArrayList list,
                XmlReader reader)
    {
        // do something
    }
}
 
// GlobalUsings.cs
global using System.Linq;
global using System.Threading.Tasks;
global using System.Collections;

tip

The reverse transformation from global to local using directives is available via the Convert to Non-Global Using refactoring.