打开oracle连接时，连接对象为空

Question

我正在尝试连接到我的控制器中的 oracle 数据库：

 using Oracle.DataAccess.Client;
 using Oracle.DataAccess.Types;

 // Other code

 OracleConnection con;
 con = new OracleConnection();

 con.ConnectionString = "DATA SOURCE=<DSOURCE_NAME>;PERSIST SECURITY INFO=True;USER ID=******;PASSWORD=*******";

 con.Open();

连接测试成功，我可以在 Visual Studio 的服务器资源管理器中浏览表、函数等，但是当我尝试执行上面的代码时，我始终得到 [NullReferenceException: Object reference not set to an instance of an object.] con.Open(); 行。

这是我第一次使用 ODP for .NET，而且我通常也是 C# 的新手。关于可能是什么问题的任何想法？

堆栈跟踪：

    Source Error: 


Line 27: 
Line 28: 
Line 29:             con.Open();
Line 30: 

Source File: c:\Program Files\Project\source\Project\Project\Areas\Custom\Controllers\HomeController.cs    Line: 29 

 Stack Trace: 


    [NullReferenceException: Object reference not set to an instance of an object.]
   Oracle.DataAccess.Client.OracleConnection.Open() +12156
   Project.Areas.Custom.Controllers.HomeController.Id() in c:\Program Files\Project\source\Project\Project\Areas\Custom\Controllers\HomeController.cs:29
   lambda_method(Closure , ControllerBase , Object[] ) +101
   System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) +59
   System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +435
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +60
   System.Web.Mvc.Async.ActionInvocation.InvokeSynchronousActionMethod() +76
   System.Web.Mvc.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState) +36
   System.Web.Mvc.Async.WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult) +73
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +136
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +102
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +49
   System.Web.Mvc.Async.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d() +117
   System.Web.Mvc.Async.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f() +323
   System.Web.Mvc.Async.<>c__DisplayClass33.<BeginInvokeActionMethodWithFilters>b__32(IAsyncResult asyncResult) +44
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +47
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +136
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +102
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +50
   System.Web.Mvc.Async.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() +72
   System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +185
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +42
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +133
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +40
   System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +34
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +70
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +133
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +37
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +44
   System.Web.Mvc.Controller.<BeginExecute>b__15(IAsyncResult asyncResult, Controller controller) +39
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +62
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +133
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +37
   System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +39
   System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +39
   System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +39
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +70
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +133
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +37
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +40
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +38
   System.Web.Mvc.<>c__DisplayClassa.<EndProcessRequest>b__9() +44
   System.Web.Mvc.<>c__DisplayClass4.<Wrap>b__3() +34
   System.Web.Mvc.ServerExecuteHttpHandlerWrapper.Wrap(Func`1 func) +69
   System.Web.Mvc.ServerExecuteHttpHandlerWrapper.Wrap(Action action) +123
   System.Web.Mvc.ServerExecuteHttpHandlerAsyncWrapper.EndProcessRequest(IAsyncResult result) +133
   System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage, VirtualPath path, VirtualPath filePath, String physPath, Exception error, String queryStringOverride) +1556

[HttpException (0x80004005): Error executing child request for handler 'System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerAsyncWrapper'.]
   System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage, VirtualPath path, VirtualPath filePath, String physPath, Exception error, String queryStringOverride) +3424518
   System.Web.HttpServerUtility.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage) +77
   System.Web.HttpServerUtility.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm) +29
   System.Web.HttpServerUtilityWrapper.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm) +24
   System.Web.Mvc.Html.ChildActionExtensions.ActionHelper(HtmlHelper htmlHelper, String actionName, String controllerName, RouteValueDictionary routeValues, TextWriter textWriter) +977
   System.Web.Mvc.Html.ChildActionExtensions.Action(HtmlHelper htmlHelper, String actionName, String controllerName, RouteValueDictionary routeValues) +112
   System.Web.Mvc.Html.ChildActionExtensions.Action(HtmlHelper htmlHelper, String actionName, String controllerName) +47
   ASP._Page_Areas_Custom_Views_Home_Home_cshtml.Execute() in c:\Program Files\Project\source\Project\Project\Areas\Custom\Views\Home\Home.cshtml:13
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +270
   System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +122
   System.Web.WebPages.StartPage.RunPage() +63
   System.Web.WebPages.StartPage.ExecutePageHierarchy() +100
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +131
   System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance) +695
   System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer) +382
   System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) +431
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) +39
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +116
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +529
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) +106
   System.Web.Mvc.Async.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() +321
   System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +185
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +42
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +133
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +40
   System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +34
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +70
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +133
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +37
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +44
   System.Web.Mvc.Controller.<BeginExecute>b__15(IAsyncResult asyncResult, Controller controller) +39
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +62
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +133
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +37
   System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +39
   System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +39
   System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +39
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +70
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +133
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +37
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +40
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +38
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9711525
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

Answer 1

在 open() 调用周围添加一个 try catch 块并解决 OracleException 中显示的 ORA 错误。

Answer 2

我开始使用ODP.NET时遇到了同样的问题。

您可以这样调整您的代码：

try
{
    OracleConnection con;
    con = new OracleConnection();

    con.ConnectionString = "DATA SOURCE=<DSOURCE_NAME>;PERSIST SECURITY INFO=True;USER ID=******;PASSWORD=*******";

    con.Open();
}
catch (OracleException ex)
{
    Console.WriteLine("Oracle Exception Message");
    Console.WriteLine("Exception Message: " + ex.Message);
    Console.WriteLine("Exception Source: " + ex.Source);
}
catch (Exception ex)
{
    Console.WriteLine("Exception Message");
    Console.WriteLine("Exception Message: " + ex.Message);
    Console.WriteLine("Exception Source: " + ex.Source);
}

您可以在此处获得有关错误的更多信息：ORA-12154

问题出在连接字符串中的 Data Source。我假设它看起来像这样：Data Source=Server.Source 就像您可以在计算机上的 TNSNAMES.ORA 文件中找到的那样。

问题是 ODP.NET 不像 Visual Studio 那样读取 TNSNAMES.ORA 文件。

您有多种选择来解决这个问题：

编辑您的 Web.Config 或 App.config 文件，告诉 ODP.NET 如何处理您的来源。
将您的 TNSNAMES.ORA 文件复制到与 .exe 相同的目录中。（如果它不是网络应用程序）
更改 Data Source 以编写长版本而不是别名。例如。 : Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=sales-server)......)))

我最喜欢的方法是 #3。当你遇到问题时，调试起来会容易很多。

您可以在 Configuring Oracle Data Provider for .NET 文档的 数据源部分 中找到更多信息。

Answer 3

我认为某处尝试过度，或者堆栈让我认为这是一个异步控制器调用，但您没有使用异步方法 ("async all the way")。

解释：

这里还有其他事情。虽然我很高兴 try/catch 块的建议可以帮助您解决问题，但简化的代码块不应该需要它们 - 应该抛出 ora 异常来代替空引用异常。

Answer 4

在我的版本中，Oracle Path 变量设置错误（因为之前安装了另一个 Oracle 客户端）。所以我建议也考虑一下这个可能性。

通过我的电脑（这台电脑）->属性->高级系统设置->高级->环境变量->路径您可以编辑 Oracle Home 路径。

Answer 5

我有同样的问题并解决了添加到我的 C# 项目参考 Oracle.ManagedDataAccess 而不是 Oracle.DataAccess.
为此，请转到 （工具/Nugget 包管理器/解决方案的 Nugget 包管理器） 浏览 Oracle References 和 select Oracle.ManagedDataAccess.
然后，您需要评论或删除对 ManagedDataAccess 的实际 DataAccess 调用：

//using Oracle.DataAccess.Client; 
//using Oracle.DataAccess.Types;
using Oracle.ManagedDataAccess.Client;

无需更改您的连接代码，只需更改使用编码即可。运行后，您可以从项目引用中删除 Oracle.DataAccess

打开oracle连接时，连接对象为空

When opening an oracle connection, connection object is null

.net

c#

oracle

odp.net