oracle 打开oracle连接时，连接对象为空

When opening an oracle connection, connection object is null

提问by Dan

I am trying to connect to an oracle database in my controller:

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();

The connection test is successful and I can navigate through tables, functions, etc. in Visual Studio's Server Explorer, but when I try to execute the above code I consistently get[NullReferenceException: Object reference not set to an instance of an object.]on the con.Open();line.

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述代码时，我始终无法[NullReferenceException: Object reference not set to an instance of an object.]上con.Open();线。

This is my first time using ODP for .NET and I am generally new to C# as well. Any ideas on what could be the problem?

这是我第一次将 ODP 用于 .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？

Stack Trace:

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

采纳答案by Christian Shay

Add a try catch block around the open() call and resolve the ORA error that shows up in the OracleException.

在 open() 调用周围添加 try catch 块并解决出现在 OracleException 中的 ORA 错误。

回答by ijimenez123

I had same problem and solved adding to my C# Project References Oracle.ManagedDataAccessinstead of Oracle.DataAccess.
To do this go to (Tools / Nugget Package Manager / Nugget Package Manager for Solution)browse for Oracle References and select Oracle.ManagedDataAccess.
Then you need to comment or delete your actual DataAccess calls to ManagedDataAccess as:

我遇到了同样的问题并解决了添加到我的 C# 项目引用 Oracle.ManagedDataAccess而不是Oracle.DataAccess 的问题。
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 并选择Oracle.ManagedDataAccess。
然后，您需要将您对 ManagedDataAccess 的实际 DataAccess 调用注释或删除为：

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

No need to change your Connection Code, only the using coding. After it works you can delete Oracle.DataAccess from your Project References

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

回答by Maxime

I had the same problem when I started to use ODP.NET.

当我开始使用 ODP.NET 时，我遇到了同样的问题。

You can adjust your code like this:

您可以像这样调整代码：

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);
}

You can get more information about your error here: ORA-12154

您可以在此处获取有关错误的更多信息：ORA-12154

The problem is your Data Sourcein your connection string. I assume that it looks like this: Data Source=Server.Sourceas you could find in your TNSNAMES.ORAfile on your computer.

问题出Data Source在您的连接字符串中。我假设它看起来像这样：Data Source=Server.Source正如您可以在TNSNAMES.ORA计算机上的文件中找到的那样。

The problem is that ODP.NET does not read the TNSNAMES.ORAfile as Visual Studio does.

问题是 ODP.NET 不像TNSNAMES.ORAVisual Studio 那样读取文件。

You have multiple choices to solve this issue:

您有多种选择来解决此问题：

1. Edit your Web.Configor App.configfile to tell ODP.NET how to handle your source.
2. Copy your TNSNAMES.ORAfile in the same directory as the .exe. (If it's not a web app)
3. Change the Data Sourcein order to write the long version instead of the alias. E.g. : Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=sales-server)......)))

1. 编辑您的Web.Config或App.config文件以告诉 ODP.NET 如何处理您的源。
2. 将您的TNSNAMES.ORA文件复制到与.exe. （如果它不是网络应用程序）
3. 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)......)))

My favorite method is the #3. It's a lot easier to debug when you have a problem.

我最喜欢的方法是#3。当您遇到问题时，调试起来要容易得多。

You can find more information in the dataSources Sectionof the Configuring Oracle Data Provider for .NETdocumentation.

您可以在为 .NET 配置 Oracle 数据提供程序文档的数据源部分中找到更多信息。

回答by nooaa

In my version the Oracle Path variable was set wrong ( cos there was another Oracle client installation before). So i suggest to take this possiblity into consideration too.

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）。所以我建议也考虑这种可能性。

By following the My computer(this PC)->Properties->Advanced System Settings->Advanced->Enviromental Variables->Path you can edit Oracle Home path.

按照我的电脑（这台电脑）->属性->高级系统设置->高级->环境变量->路径可以编辑Oracle Home路径。

回答by b_levitt

I think there's an over-reaching try somewhere, or the stack makes me think this is an async controller call, but you're not using the async methods ("async all the way").

我认为某处有过度尝试，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（“一路异步”）。

Explanation:

解释：

Something else is going on here. While I'm glad suggestions for a try/catch block helped you resolve the issue, they should not have been required with the simplified code bock - the ora exception should have been thrown in place of the null reference exception.

这里正在发生其他事情。虽然我很高兴关于 try/catch 块的建议帮助您解决了问题，但简化代码块不应该要求它们 - 应该抛出 ora 异常代替空引用异常。