P/Invoke
P/Invoke (Platform Invocation Services) is a feature in .NET that enables managed code (e.g., C# or VB.NET) to call unmanaged functions from dynamic-link libraries (DLLs), such as those written in C or C++. It provides a mechanism for interoperability between .NET applications and native code, allowing access to system APIs, third-party libraries, or legacy components. This is achieved by declaring external methods with specific attributes and data type mappings.
Developers should learn P/Invoke when building .NET applications that need to interact with native Windows APIs (e.g., for system-level tasks like file operations or hardware access), integrate with legacy C/C++ libraries, or optimize performance-critical sections with unmanaged code. It is essential for scenarios where managed .NET libraries are unavailable, such as calling functions from user32.dll or kernel32.dll in Windows, or when migrating legacy systems to .NET while preserving existing native components.