- Posts: 95
- Thank you received: 3
Online Forums
Technical support is provided through Support Forums below. Anybody can view them; you need to Register/Login to our site (see links in upper right corner) in order to Post questions. You do not have to be a licensed user of our product.
Please read Rules for forum posts before reporting your issue or asking a question. OPC Labs team is actively monitoring the forums, and replies as soon as possible. Various technical information can also be found in our Knowledge Base. For your convenience, we have also assembled a Frequently Asked Questions page.
Do not use the Contact page for technical issues.
- Forum
- Discussions
- QuickOPC-Classic in .NET
- Reading, Writing, Subscriptions, Property Access
- Object reference not set to an instance of an object. QuickOPC 2020.3 alpha
Object reference not set to an instance of an object. QuickOPC 2020.3 alpha
12 Nov 2020 08:55 #9133
by Andriy
Replied by Andriy on topic Object reference not set to an instance of an object. QuickOPC 2020.3 alpha
Hello,
Thank you for your assistance,
I'm awaiting approval from the customer to update installation. I'll keep you informed
Regards
Thank you for your assistance,
I'm awaiting approval from the customer to update installation. I'll keep you informed
Regards
Please Log in or Create an account to join the conversation.
10 Nov 2020 19:47 #9120
by support
Replied by support on topic Object reference not set to an instance of an object. QuickOPC 2020.3 alpha
Hello,
can you please rebuild and test with 5.59.0-rev23 from nuget.org. In relation to this issue, what we are looking for is the call stack again (the innermost exception being the most important; now, there will likely be two of them, the actual exception thrown will be InvalidOperationException ,with inner exception of type NullReferenceException).
Thank you very much for cooperation.
Note that there were some changes; specifically, the EnableNativeClient and EnableNetApiClient properties are now under InstanceParameters and thus need to be set on each new instance of EasyDAClient separately. See kb.opclabs.com/What%27s_new_in_QuickOPC_2020.3 for more information about the changes.
Best regards
can you please rebuild and test with 5.59.0-rev23 from nuget.org. In relation to this issue, what we are looking for is the call stack again (the innermost exception being the most important; now, there will likely be two of them, the actual exception thrown will be InvalidOperationException ,with inner exception of type NullReferenceException).
Thank you very much for cooperation.
Note that there were some changes; specifically, the EnableNativeClient and EnableNetApiClient properties are now under InstanceParameters and thus need to be set on each new instance of EasyDAClient separately. See kb.opclabs.com/What%27s_new_in_QuickOPC_2020.3 for more information about the changes.
Best regards
Please Log in or Create an account to join the conversation.
10 Nov 2020 16:14 #9119
by Andriy
Replied by Andriy on topic Object reference not set to an instance of an object. QuickOPC 2020.3 alpha
Hello,
You are right, I need nuget packages
Regards
You are right, I need nuget packages
Regards
Please Log in or Create an account to join the conversation.
10 Nov 2020 15:15 #9118
by support
Replied by support on topic Object reference not set to an instance of an object. QuickOPC 2020.3 alpha
Thank you.
You need the NuGet packages and do not need the standalone installer, is that correct?
Regards
You need the NuGet packages and do not need the standalone installer, is that correct?
Regards
Please Log in or Create an account to join the conversation.
10 Nov 2020 11:12 #9113
by Andriy
Replied by Andriy on topic Object reference not set to an instance of an object. QuickOPC 2020.3 alpha
Hello,
Here are the answers to your questions
1. I don't have a reproducible scenario. Unfortunately, this exception happens on customer site
2. I can't debug the application on the customer site
3. Yes, I can use special build of QuickOpc.
Regards
Here are the answers to your questions
1. I don't have a reproducible scenario. Unfortunately, this exception happens on customer site
2. I can't debug the application on the customer site
3. Yes, I can use special build of QuickOpc.
Regards
Please Log in or Create an account to join the conversation.
09 Nov 2020 20:26 #9109
by support
Replied by support on topic Object reference not set to an instance of an object. QuickOPC 2020.3 alpha
Hello,
the developer was unable to reproduce it, and he was also unable to find the issue by analyzing the code. The problem is that with the way the code is written, the original call stack gets overwritten - it is not the one you could have provided.
Questions:
1. Do you have a reproducible scenario, or hints as to how to "likely" get the error?
2. Can you perhaps reproduce the problem under debugger, with exception settings set so that it breaks the exception when a NullReferenceException is thrown (not just when it is unhandled), and when that happens, capture the call stack for us?
3. If none of the above is possible or gives result, would you be willing to try to reproduce on your side with one more "special" build of QuickOPC, which would have the error handling modified just for this case, to presumably catch the proper information we need (the original call stack etc.)?
Kind regards
the developer was unable to reproduce it, and he was also unable to find the issue by analyzing the code. The problem is that with the way the code is written, the original call stack gets overwritten - it is not the one you could have provided.
Questions:
1. Do you have a reproducible scenario, or hints as to how to "likely" get the error?
2. Can you perhaps reproduce the problem under debugger, with exception settings set so that it breaks the exception when a NullReferenceException is thrown (not just when it is unhandled), and when that happens, capture the call stack for us?
3. If none of the above is possible or gives result, would you be willing to try to reproduce on your side with one more "special" build of QuickOPC, which would have the error handling modified just for this case, to presumably catch the proper information we need (the original call stack etc.)?
Kind regards
Please Log in or Create an account to join the conversation.
09 Nov 2020 18:31 #9108
by Andriy
Replied by Andriy on topic Object reference not set to an instance of an object. QuickOPC 2020.3 alpha
Hello,
Do you have any updates?
Regards
Do you have any updates?
Regards
Please Log in or Create an account to join the conversation.
27 Oct 2020 06:36 #9028
by support
Replied by support on topic Object reference not set to an instance of an object. QuickOPC 2020.3 alpha
Oh, I see - in any new report, you need to explicitly mention the fact that you have been instructed to use the prerelease version - as you did in this post.
I have forwarded the issue to the programmer who worked on this part. Will let you know here when I know more.
Kind regards
I have forwarded the issue to the programmer who worked on this part. Will let you know here when I know more.
Kind regards
Please Log in or Create an account to join the conversation.
26 Oct 2020 18:00 #9027
by Andriy
Hello,
We got an email confirmation from OPC Labs regarding the use of “alpha” version of QuickOPC 2020.3 in test mode to solve the following problem
www.opclabs.com/forum/reading-writing-subscriptions-property...-blocked-subscribe-unsubscribe
Recently, I found a null-reference exception that causes my application to crash. Could you fix that?
QuickOpc version 5.59.0-rev13
EnableNativeClient: False
the call stack is slightly differentRegards
We got an email confirmation from OPC Labs regarding the use of “alpha” version of QuickOPC 2020.3 in test mode to solve the following problem
www.opclabs.com/forum/reading-writing-subscriptions-property...-blocked-subscribe-unsubscribe
Recently, I found a null-reference exception that causes my application to crash. Could you fix that?
QuickOpc version 5.59.0-rev13
EnableNativeClient: False
System.NullReferenceException: Object reference not set to an instance of an object.
at OpcLabs.EasyOpc.Implementation.NetApi.DataAccess.NetApiEasyDAClient.CheckException(Exception exception, Boolean isOtherMethod)
at OpcLabs.EasyOpc.Implementation.NetApi.DataAccess.NetApiSubscription.RemoveItemsFromOneSubscription(NetApiOpcDaSubscription subscription, IList`1 itemsToRemove, Boolean freeHandleForSucceeded, NetApiCacheEventArgs cacheEventsArgs)
at OpcLabs.EasyOpc.Implementation.NetApi.DataAccess.NetApiSubscription.RemoveItems(IList`1 itemsToRemove)
at OpcLabs.EasyOpc.Implementation.NetApi.DataAccess.NetApiSubscription.RemoveItemsL1(IEnumerable`1 handles)
at OpcLabs.EasyOpc.Implementation.NetApi.DataAccess.NetApiSubscription.OnTimer(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.TimerQueueTimer.CallCallback()
at System.Threading.TimerQueueTimer.Fire()
at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
at System.Threading.ThreadPoolWorkQueue.Dispatch()System.NullReferenceException: Object reference not set to an instance of an object.
at OpcLabs.EasyOpc.Implementation.NetApi.DataAccess.NetApiEasyDAClient.CheckException(Exception exception, Boolean isOtherMethod)
at OpcLabs.EasyOpc.Implementation.NetApi.DataAccess.NetApiSubscription.RemoveItemsFromOneSubscription(NetApiOpcDaSubscription subscription, IList`1 itemsToRemove, Boolean freeHandleForSucceeded, NetApiCacheEventArgs cacheEventsArgs)
at OpcLabs.EasyOpc.Implementation.NetApi.DataAccess.NetApiSubscription.RemoveItems(IList`1 itemsToRemove)
at OpcLabs.EasyOpc.Implementation.NetApi.DataAccess.NetApiSubscription.RemoveItemsL1(IEnumerable`1 handles)
at OpcLabs.EasyOpc.Implementation.NetApi.DataAccess.NetApiSubscription.OnTimer(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.TimerQueueTimer.CallCallback()
at System.Threading.TimerQueueTimer.Fire()
at System.Threading.TimerQueue.FireNextTimers()Please Log in or Create an account to join the conversation.
Moderators: support
- Forum
- Discussions
- QuickOPC-Classic in .NET
- Reading, Writing, Subscriptions, Property Access
- Object reference not set to an instance of an object. QuickOPC 2020.3 alpha
Time to create page: 0.061 seconds