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  5. QuickOPC-Classic in .NET
  7. Reading, Writing, Subscriptions, Property Access
  9. Object Disposed Exception -> Unhandled

Object Disposed Exception -> Unhandled

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27 Feb 2022 15:23 #10658 by mpp
Replied by mpp on topic Object Disposed Exception -> Unhandled
The try-catch is not handling the exception.
I can try to extract just the code that use your lib and prepare a sample csproj but it really is just a timer that read some variables.

Let me know if you need it.


Thanks

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27 Feb 2022 14:04 #10657 by mpp
Replied by mpp on topic Object Disposed Exception -> Unhandled
It is just a timer that check a variable every 10seconds.
If that variable assumes a certain value I write a value to that variable and then read a block of other variables.

This is the code I use to read a single variable:
DAVtq valueRead = null;
var rp = new DAReadParameters() { DataSource = (descriptor.ReadDevice ? DADataSource.Device : DADataSource.Cache) };
var sd = new ServerDescriptor() { MachineName = _connection.MachineName, ServerClass = _connection.ServerName };
var id = new DAItemDescriptor() { ItemId = _connection.PLC_ID + "." + descriptor.Key };
 
await Task.Run(() => valueRead = _client.ReadItem(sd, id, rp)).ConfigureAwait(false);

The approach is similar for multiple items read and for writing.
Should I put a try-catch in the lambda?

Thanks

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27 Feb 2022 13:42 #10656 by support
Replied by support on topic Object Disposed Exception -> Unhandled
Hello,

do you perhaps have a code/project (the smaller the better) that can reproduce this problem?

Best regards

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27 Feb 2022 11:11 #10655 by mpp
Object Disposed Exception -> Unhandled was created by mpp
Hi!

I'm having an issue with the DA client. This is what it is register as an unhandled exception on the windows event log:
Application: Statistics.PLCService.exe
CoreCLR Version: 6.0.21.52210
.NET Version: 6.0.0
Description: The process was terminated due to an unhandled exception.
Exception Info: System.ObjectDisposedException: Cannot access a disposed object.
Object name: 'OpcLabs.EasyOpc.Implementation.NetApi.DataAccess.NetApiEasyDAClient'.
   at OpcLabs.EasyOpc.Implementation.NetApi.DataAccess.NetApiEasyDAClient.UnsubscribeMultipleItems(IEnumerable`1 handlesToUnsubscribe)
   at OpcLabs.EasyOpc.DataAccess.Implementation.ForwardingEasyDAClient.UnsubscribeMultipleItems(IEnumerable`1 handlesToUnsubscribe)
   at OpcLabs.EasyOpc.DataAccess.Implementation.ForwardingEasyDAClient.UnsubscribeMultipleItems(IEnumerable`1 handlesToUnsubscribe)
   at OpcLabs.EasyOpc.DataAccess.Implementation.DelegatingEasyDAClient.UnsubscribeMultipleItems(IEnumerable`1 handlesToUnsubscribe)
   at OpcLabs.EasyOpc.DataAccess.Implementation.HandleMappingEasyDAClient.UnsubscribeMultipleItems(IEnumerable`1 handlesToUnsubscribe)
   at OpcLabs.EasyOpc.DataAccess.Implementation.DelegatingEasyDAClient.DelegatedUnsubscribeMultipleItemsWithHandleMapping(IEnumerable`1 handlesToUnsubscribe)
   at OpcLabs.EasyOpc.DataAccess.Implementation.DelegatingEasyDAClient.<>c__DisplayClass13_0.<UnsubscribeMultipleItems>b__0()
   at OpcLabs.EasyOpc.DataAccess.Implementation.DelegatingEasyDAClient.<>c__DisplayClass109_0.<QueueBackEndAction>b__0()
   at OpcLabs.BaseLib.Threading.Extensions.FifoExecutionExtension.<>c__DisplayClass0_0.<QueueUserWorkItem>b__0(Object _)
   at OpcLabs.BaseLib.Threading.WorkItem.<>c.<.cctor>b__17_0(Object state)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location ---
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
   at OpcLabs.BaseLib.Threading.WorkItem.Execute()
   at OpcLabs.BaseLib.Threading.FifoExecution.ProcessQueuedItems(Object ignored)
   at System.Threading.QueueUserWorkItemCallbackDefaultContext.Execute()
   at System.Threading.ThreadPoolWorkQueue.Dispatch()
   at System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart()
   at System.Threading.Thread.StartCallback()

I'm using the last nuget package 5.62.1032. It's weird because I'm using the library quite extensively in the applications that are running together but only in this one I get this exception and I cannot understand where it is originated as I'm not subscribing to any opc variable.

Do you have any idea/suggestion on something I can do to fix this issue?

Thanks in advance

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  5. QuickOPC-Classic in .NET
  7. Reading, Writing, Subscriptions, Property Access
  9. Object Disposed Exception -> Unhandled
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