using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Reflection;
using System.Text.RegularExpressions;
using System.Windows.Forms;

namespace LicenseExamination
{
    static class Program
    {
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            AppDomain.CurrentDomain.AssemblyResolve += LoadDirDll.AssemblyResolve;
 
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form());
        }

        /// <summary> 已加载DLL
        /// </summary>
        private static Dictionary<string, Assembly> LoadedDlls = new Dictionary<string, Assembly>();
        /// </summary>
        /// <summary> 在对程序集解释失败时触发
        /// </summary>
        /// <param name="sender">AppDomain</param>
        /// <param name="args">事件参数</param>
        public static Assembly AssemblyResolve(object sender, ResolveEventArgs args)
        {
            var assName = new AssemblyName(args.Name).FullName;
            try
            {
                //判断是否已经加载
                if (LoadedDlls.ContainsKey(assName))
                {
                    return LoadedDlls[assName];
                }
                string file = Application.StartupPath + "\\libs\\" + assName.Split(',')[0] + ".dll";
                byte[] buff = System.IO.File.ReadAllBytes(file);
                var da = Assembly.Load(buff);
                return da;
            }
            catch (Exception ex)
            {
                throw new DllNotFoundException(assName);//否则抛出加载失败的异常
            }
        }

    }
}

main函数前面增加解析事件注册

AppDomain.CurrentDomain.AssemblyResolve += LoadDirDll.AssemblyResolve;

string file = Application.StartupPath + "\\libs\\"

可修改为任意目录

根据区域语言加载dll

using System.Reflection;
using System.IO;
using System.Globalization;

    public class Program
    {
        /// <summary>
        /// 使用静态构造函数来绑定解析程序集失败事件
        /// </summary>
        static Program()
        {
            AppDomain.CurrentDomain.AssemblyResolve += OnResolveAssembly;
        }

        [STAThreadAttribute]
        public static void Main()
        {
            App.Main(); //启动WPF项目
        }

        //解析程序集失败，会加载对应的程序集
        private static Assembly OnResolveAssembly(object sender, ResolveEventArgs args)
        {
            Assembly executingAssembly = Assembly.GetExecutingAssembly();
            AssemblyName assemblyName = new AssemblyName(args.Name);

            var path = assemblyName.Name + ".dll";
            //判断程序集的区域性
            if (!assemblyName.CultureInfo.Equals(CultureInfo.InvariantCulture))
            {
                path = string.Format(@"{0}\{1}", assemblyName.CultureInfo, path);
            }

            using (Stream stream = executingAssembly.GetManifestResourceStream(path))
            {
                if (stream == null) return null;

                var assemblyRawBytes = new byte[stream.Length];
                stream.Read(assemblyRawBytes, 0, assemblyRawBytes.Length);
                return Assembly.Load(assemblyRawBytes);
            }
        }
    }