How Can I Efficiently Find All Derived Types of a Given Type Using Reflection?

Find Derived Types of a Type

In many cases, it is necessary to determine the derived types of a given type. However, the default approaches, such as iterating through all types in loaded assemblies and checking their assignability, can be inefficient.

Using Reflection

A more performant solution involves using reflection to retrieve the derived types. Here's a LINQ-based approach:

var listOfDerivedTypes = (
    from domainAssembly in AppDomain.CurrentDomain.GetAssemblies()
    from assemblyType in domainAssembly.GetTypes()
    where type.IsAssignableFrom(assemblyType)
    select assemblyType).ToArray();

This method iterates through all assemblies and checks if the given type is assignable to each assembly type.

Fluent Version

For improved readability, you can use a fluent version:

var listOfDerivedTypes = AppDomain.CurrentDomain.GetAssemblies()
    .SelectMany(domainAssembly => domainAssembly.GetTypes())
    .Where(assemblyType => type.IsAssignableFrom(assemblyType))
    .ToArray();

Considerations

• Reflection Overhead: Each invocation of the reflection methods incurs an overhead. For repetitive operations, consider loading the types once and using a caching mechanism, such as Lazy.
• Exported Types: To retrieve only publicly visible types, consider using domainAssembly.GetExportedTypes() instead of domainAssembly.GetTypes().
• Base Type Inclusion: By default, the returned list will include the base type. To exclude it, use the following additional condition: && assemblyType != typeof(baseType).
• Abstract Classes: If you only want concrete derived classes, add the condition: && !assemblyType.IsAbstract.
• Generic Types: Handling generic types requires specific techniques, which are not covered in this response. Refer to the provided links for more information.

The above is the detailed content of How Can I Efficiently Find All Derived Types of a Given Type Using Reflection?. For more information, please follow other related articles on the PHP Chinese website!