How to convert plugin assembly (dll) into base 64 bytes using console application (C#).

 using System;

using System.IO;

using System.ServiceModel.Description;

using Microsoft.Rest;

using Microsoft.Xrm.Sdk;

using Microsoft.Xrm.Sdk.Query;

using Microsoft.Xrm.Tooling.Connector;

namespace ConsoleApp2

{

    internal class Program

    {

        static void Main(string[] args)

        {

            string connectionString = @"AuthType=OAuth;

                Username=*****************;

                Password=*****************;

                Url=https://*****************.crm8.dynamics.com;

                AppId=*****************;

                 LoginPrompt=Auto";

            Console.WriteLine("Connecting to Dynamics 365..");

            using (CrmServiceClient serviceClient = new CrmServiceClient(connectionString))

            {

                if (!serviceClient.IsReady)

                {

                    Console.WriteLine("Failed to connect: " + serviceClient.LastCrmError);

                    return;

                }

                IOrganizationService service = (IOrganizationService)serviceClient.OrganizationWebProxyClient ?? (IOrganizationService)serviceClient.OrganizationServiceProxy;

                Console.WriteLine("connected to Dynamics Crm ");

                QueryExpression query = new QueryExpression("pluginassembly")

                {

                    ColumnSet = new ColumnSet("name", "content")

                };

                EntityCollection results = service.RetrieveMultiple(query);

                foreach (Entity plugin in results.Entities)

                {

                    string name = plugin.GetAttributeValue<string>("name");

                    string content = plugin.GetAttributeValue<string>("content");

                    if (string.IsNullOrEmpty(content))

                    {

                        Console.WriteLine($"Assembly '{name}' has no content.");

                        continue;

                    }

                    byte[] dllBytes = Convert.FromBase64String(content);

                    string fileName = $"{name}.dll";

                    File.WriteAllBytes(fileName, dllBytes);

                    Console.WriteLine($"Downloaded: {fileName}");

                }

                Console.WriteLine("All assemblies downloaded successfully.");

            }

        }

    }

}

Notes -Replace credentials as per your  CRM environment.