我刚刚将一个用户和角色 asp 数据库部署到一个网站，但我遇到了这个异常
对象引用未设置到对象的实例。 说明:在执行当前 Web 请求期间发生未处理的异常。请查看堆栈跟踪以获取有关错误及其在代码中的来源的更多信息。
Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.
Source Error:
Line 41: #endregion
Line 42:
Line 43: public UsersAndRolesDataContext() :
Line 44: base(global::System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionString" ].ConnectionString, mappingSource)
Line 45: {
Source File: d:\hosting\7122544\html\SSM\App_Code\UsersAndRoles.designer.cs Line: 43
Stack Trace:
[NullReferenceException: Object reference not set to an instance of an object.]
UsersAndRolesDataContext..ctor() in d:\hosting\7122544\html\SSM\App_Code \UsersAndRoles.designer.cs:43
admin_ManageUsers..ctor() in d:\hosting\7122544\html\SSM\admin\ManageUsers.aspx.cs:11
ASP.admin_manageusers_aspx..ctor() in c:\windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\ssm\5b123e8f\6bb9cf4c\App_Web_tz5adhff.10.cs:0
__ASP.FastObjectFactory_app_web_tz5adhff.Create_ASP_admin_manageusers_aspx() in c:\windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\ssm\5b123e8f\6bb9cf4c\App_Web_tz5adhff.12.cs:0
System.Web.Compilation.BuildResultCompiledType.CreateInstance() +32
System.Web.Compilation.BuildManager.CreateInstanceFromVirtualPath(VirtualPath virtualPath, Type requiredBaseType, HttpContext context, Boolean allowCrossApp) +109
System.Web.UI.PageHandlerFactory.GetHandlerHelper(HttpContext context, String requestType, VirtualPath virtualPath, String physicalPath) +31
System.Web.UI.PageHandlerFactory.GetHandler(HttpContext context, String requestType, String virtualPath, String path) +37
System.Web.MaterializeHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +334
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +184
最佳答案
您可能缺少配置文件中名为 ConnectionString 的连接字符串，因此 System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionString"] 返回 null。
关于c# - 我在 Linq To SQL 数据上下文中遇到空引用异常，我什至不知道从哪里开始，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/6434295/