旧的ASP.NET代码可在一台计算机上运行，​​而不是另一台计算机上？

如何解决旧的ASP.NET代码可在一台计算机上运行，​​而不是另一台计算机上？

所以在我的global.asax中，我有以下代码：

Inventory.BusinessTier bt = new Inventory.BusinessTier();
string UserLogin = bt.ExtractLogin (Request.ServerVariables ["AUTH_USER"]);
Inventory.User myUser = new Inventory.User (UserLogin);
Session ["User"] = myUser;

在一台开发PC上运行正常，但是使用相同版本的Visual Studio，它在第三行出现以下错误：

System.TypeInitializationException：'用于的类型初始值设定项 “ Inventory.DataTier”引发了异常。 内部异常 NullReferenceException：对象引用未设置为的实例 对象。

除了在我的web.config中添加模拟的行（现在必须存在）之外，我没有更改任何东西。有没有办法获取更多信息？我什至无法跟踪它，因为如果我在User对象构造函数中放入调试行，它永远不会命中它。我有点茫然。不胜感激。

编辑以回答以下问题：

InventoryUser是一个非常简单的用户对象，它从数据库中读取当前信息，并将一些基本用户信息存储在属性中，例如UserID，Role，RoleID和IsAdmin。

DataTier类是与数据库交互的类。它用于多个项目，所以我很确定这不是问题。无论如何，我都尝试粘贴代码，但超出了发布的限制。

我可以肯定地确定问题与用户类别有关。它很短，所以我可以将其粘贴在这里：

using System;
using System.Data;

// This is the user business object.  It contains information pertaining to the current user of the application.  Notably,it
// contains the department ID,which determines what inventory items the user will see when using the application.  Only
// specified employees with admin access can see all items for all departments,and that is determined by a specific department ID.

namespace Inventory {

    public class User {

        private Guid _UserID;
        private Guid _RoleID;
        private Guid _UserDepartmentID;
        private string _UserRole        = "";
        private string _UserName        = "";
        private bool _IsAuthorizedUser  = false;
        private bool _IsAdmin           = false;

        // Attribute declarations
        public Guid UserID {
            get {
                return _UserID;
            }
            set {
                _UserID = value;
            }
        }
        public string UserRole {
            get {
                return _UserRole;
            }
            set {
                _UserRole = value;
            }
        }
        public Guid RoleID {
            get {
                return _RoleID;
            }
            set {
                _RoleID = value;
            }
        }
        public string UserName {
            get {
                return _UserName;
            }
            set {
                _UserName = value;
            }
        }
        public Guid UserDepartmentID {
            get {
                return _UserDepartmentID;
            }
            set {
                _UserDepartmentID = value;
            }
        }
        public bool IsAdmin {
            get {
                return _IsAdmin;
            }
            set {
                _IsAdmin = value;
            }
        }
        public bool IsAuthorizedUser {
            get {
                return _IsAuthorizedUser;
            }
            set {
                _IsAuthorizedUser = value;
            }
        }


        // -----------------
        // -  Constructor  -
        // -----------------
        public User (string UserLogin) {
            
            string ShortUserLogin = ExtractLogin (UserLogin);
            GetUser (ShortUserLogin);
        }

        
        // ------------------
        // -  ExtractLogin  -
        // ------------------
        public string ExtractLogin (string Login) {

            // The domain and "\" symbol must be removed from the string,leaving only the user name.

            int pos = Login.IndexOf (@"\");
            return Login.Substring (pos + 1,Login.Length - pos - 1);
        }


        // -------------
        // -  GetUser  -
        // -------------
        // This method is called to fill the user object based on the user's login.  It ultimately gets authorized user data
        // from the user table.
        public void GetUser (string UserName) {

            DataTier dt1 = new DataTier();
            DataTable dt = dt1.GetUserInfo (UserName);
            int RecordCount = dt.Rows.Count;

            switch (RecordCount) {

                case 1:                 // There is one user name match,as there should be.  This is the likely situation.
                    DataRow dr = dt.Rows[0];
                    UserID              = (Guid)dr ["UserID"];
                    UserRole            = (string)dr ["UserRole"];
                    RoleID              = (Guid)dr ["RoleID"];
                    this.UserName       = UserName;
                    UserDepartmentID    = (Guid)dr ["DepartmentID"];
                    IsAdmin             = (bool)dr ["IsAdmin"];
                    IsAuthorizedUser    = true;
                    break;

                case 0:                 // There are no user name matches (unauthorized use).
                    IsAdmin = false;
                    IsAuthorizedUser = false;
                    break;

                default:                // There are multiple user name matches (problem!).
                    IsAdmin = false;
                    IsAuthorizedUser = false;
                    break;
            }


        }


    }
}