Difference between normal DLL and .Net DLL

A normal DLL (Dynamic Link Library) and a .NET DLL (also known as a managed DLL) differ in terms of their underlying technologies and how they are compiled and executed.

What is a dll file ?

A .dll (Dynamic Link Library) file is a compiled code module that encompasses specific program functions and can be utilized by applications or modules (such as .exe or .dll) by invoking an entry point. Acting as a shared library, it enables multiple programs to concurrently access and employ its code and data. By facilitating code modularization and reuse, a .dll file promotes efficient memory usage, reduces disk space consumption, and contributes to faster loading and execution times for both the operating system and programs. This enables enhanced system performance, accelerated program execution, and optimized disk space utilization, ultimately leading to an improved overall user experience on the computer.


What is .Net dll ?

When you develop a .NET DLL (Assembly) using languages such as C# or VB.NET, it results in a Managed Assembly. A Managed Assembly adheres to the component standard defined by the .NET framework and is exclusively compatible with Microsoft.NET and can only be utilized within .NET managed applications. It comprises managed code and is executed by the .NET Runtime, providing enhanced memory management and runtime support. On the other hand, when you create a DLL with C++ language, it generates a win32/Com DLL, which is considered an "unmanaged" DLL. However, if you intend to use this "unmanaged" DLL within a .NET Language, Visual Studio automatically generates an INTEROP file, enabling you to invoke the functionality of the "unmanaged" DLL from managed code.

To use a .NET DLL (Assembly), the simplest approach is to copy the DLL file to the bin folder of the application. In contrast, normal DLL files often require registration using the "regsvr32" tool to make them accessible for use. By using these mechanisms, developers can seamlessly integrate and utilize both Managed and "unmanaged" DLLs within their .NET applications, facilitating interoperability and extending the functionality of their software solutions.


While a normal DLL is platform-specific and relies on manual memory management, a .NET DLL is platform-agnostic, utilizes automatic memory management through the .NET runtime, and offers better language interoperability within the .NET ecosystem.