工厂模式下用反射加载dll

public static T Instance(string assembly, string type)
{
    if (string.IsNullOrEmpty(type)) throw new ArgumentException("type:参数不能为空!");   
    //1、获取有效的程序集
    Assembly mAssembly = string.IsNullOrEmpty(assembly) ? Assembly.GetCallingAssembly() : Assembly.Load(assembly);
   var t = (T) mAssembly.CreateInstance(type);   //创建实例
   return t;
}