Dynamically Loading Assemblies in C#

Dynamically Loading Assemblies in C#

Introduction

In modern software development, dynamically loading assemblies enables developers to create modular and extensible applications. This approach allows for loading assemblies at runtime, providing the flexibility to add or update functionality without recompiling the entire codebase. This tutorial will walk you through the concept and provide an example of dynamically loading assemblies in C#.

Why Dynamically Load Assemblies?

Dynamically loading assemblies provides several advantages:

• Modular Development: Allows for a plug-in architecture where new modules can be added dynamically.

• Runtime Flexibility: Enables loading different implementations without modifying the core application.

• Performance Optimization: Reduces memory footprint by loading assemblies only when needed.

• Loose Coupling: Enhances maintainability and scalability by decoupling dependencies.

Implementing Dynamic Assembly Loading in C#

Below is an example demonstrating how to dynamically load an assembly and use it within an application.

Step 1: Define the Interface

To ensure that dynamically loaded assemblies follow a contract, define a common interface:

public interface ITransactionService  
{  
    Task<string> InsertAsync(TransactionRequest request);  
}  

Step 2: Load the Assembly Dynamically

private readonly ClientAssembly _clientAssembly;  
  
public MyClass(IOptions<ClientAssembly> clientAssembly)  
{  
    _clientAssembly = clientAssembly.Value;  
    _checkEvent = CreateInstance();  
}  

Step 3: Invoke Methods from the Loaded Assembly

public async Task<string> InsertAsync(long userId, SubmitLoanApplicationResponse response)  
{  
    string? output = "";  
  
    var type = typeof(ITransactionService);  
  
    if (type.IsAssignableFrom(_checkEvent.GetType()))  
    {  
        TransactionRequest transactionRequest = GetTransactionRequest(userId, response);  
  
        response.DisbursementStatus = await ((ITransactionService)_checkEvent).InsertAsync(transactionRequest);  
  
        output = await InsertTransactionLogs(userId, response, response.DisbursementStatus);  
    }  
  
    return output;  
}  

Step 4: Implement Dynamic Instance Creation

private object CreateInstance()  
{  
    var assembly = Assembly.LoadFrom("path_to_assembly.dll");  
    var type = assembly.GetType("Namespace.TransactionService");  
    return Activator.CreateInstance(type);  
}  

Conclusion

Dynamically loading assemblies in C# enhances application flexibility by enabling runtime module loading. This technique is particularly useful for plugin-based architectures, ensuring seamless updates and modular scalability. By following the approach outlined above, developers can implement dynamic assembly loading efficiently in their projects.

Key Takeaways:

• Define a common interface to ensure consistency.

• Use Assembly.LoadFrom() to load assemblies dynamically.

• Leverage Activator.CreateInstance() to create instances of types at runtime.

• Implement a flexible architecture that allows for easy modifications without recompilation.

By integrating dynamic assembly loading, you can build more robust and adaptable software solutions.