I connect my windows mobile app directly to ms-sql server using the sqlclient dll from microsoft.
Some times I get this error when trying to get some data from the server:
System.Data.SqlClient.SqlException: SqlException
at System.Data.SqlClient.SqlConnection.OnError()
at System.Data.SqlClient.SqlInternalConnection.OnError()
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning()
at System.Data.SqlClient.TdsParser.Run()
at System.Data.SqlClient.SqlDataReader.ConsumeMetaData()
at System.Data.SqlClient.SqlDataReader.get_MetaData()
at System.Data.SqlClient.SqlCommand.ExecuteReader()
at System.Data.SqlClient.SqlCommand.ExecuteReader()
Every time I have a error like this I need to try a few other things, some times the connection string is no good, or the network is not configured right or any other random problem.
Is there a way I could get a bit more info from the program so I shouldn't have to waste a few hours figuring out what might went rung?
That's basically just the stack trace. You should be able to get the Message property of the SqlException which contains the details. In some cases you will have to look at the InnerException to get to the interesting details.
Ok I found the answer... I changed: Catch ex As Exception To: Catch ex As SqlException
Now I get the specific error nicely displayed in the message.
Related
When I create a new project (web api) in Visual Studio 2019, I try running the project but I got the following error:
An unhandled exception occurred while processing the request.
SqlException: Invalid object name 'Books'.
Microsoft.Data.SqlClient.SqlCommand+<>c.b__169_0(Task result)
Did you check spelling in SqlDataReader? For me, I was misspelled. If the spelling is correct, any chance are you re-using the same name of an existing environmental variable for a different database on the same SQL Server? If the answer is yes it can be issue too.
I am new to IntelliJ. I am using Apache-Derby db and I want to find out the stack trace (i.e. all the methods called during the execution) for simple JDBC program which connects to db and executes a select query. Can anyone help me?
At the place where the query is created or any point of your interest,Create an object of Exception and print the stack trace. You can call one of the below methods
Exception ex = new Exception();
ex.getStackTrace()
ex.printStackTrace()
I am connected to a remote SQL Server instance
These queries works fine:
SELECT COUNT(*) FROM Provider
SELECT TOP 1 * FROM Provider
but these don't
SELECT * FROM Provider
SELECT TOP 2 * FROM Provider
and return this error after a long delay:
Msg 64, Level 20, State 0, Line 0
A transport-level error has occurred when receiving results from the
server. (provider: TCP Provider, error: 0 - The specified network name
is no longer available.)
What configuration should I be looking at that would allow a single row result but not a multiple row result?
I found the following
Hey mate, another thing to try i found the following and have included the URL for you. Considering the first bit of trouble shooting didn't work for you
Symptoms
The stack trace of the error resembles the following:
A transport-level error has occurred when receiving results from the server. (provider: TCP Provider, error: 0 - The specified network name is no longer available.)
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
at System.Data.SqlClient.TdsParserStateObject.ReadSniError(TdsParserStateObject stateObj, UInt32 error)
at System.Data.SqlClient.TdsParserStateObject.ReadSni(DbAsyncResult asyncResult, TdsParserStateObject stateObj)
at System.Data.SqlClient.TdsParserStateObject.ReadPacket(Int32 bytesExpected)
at System.Data.SqlClient.TdsParserStateObject.ReadBuffer()
at System.Data.SqlClient.TdsParserStateObject.ReadByte()
Cause
The error is being caused by a timeout exception for long running queries. In previous versions of Visual Studio .NET, the exception was properly represented as a exception with a timeout description.
Resolution
Set the commandtimeout property of the command object to an appropriate value. Use a value of zero to wait without an exception being thrown.
Taken from https://support.microsoft.com/en-us/kb/555938
I have coded up a cleaner type of program but getting a huge error with permissions ( I think )
The error message is printed out like so.
An unhandled exception of type 'System.UnauthorizedAccessException' occurred in mscorlib.dll
Additional information: Access to the path 'C:\Windows\CSC\v2.0.6' is denied.
And it says that the error part of the code is this line
For Each fi In DirectroyInfos.GetFiles(filter)
But here is the fill block of code.
For Each fi In DirectroyInfos.GetFiles(filter)
Try
file_count = file_count + 1
file_size = CULng(file_size + fi.Length)
FilesToDelete.Add(fi.FullName)
Catch ex As UnauthorizedAccessException
'There's really no pretty way to handle this exception
Catch ex As FileNotFoundException
'There's really no pretty way to handle this exception
End Try
I think it's some sort of permission problem I have windows 7 and have noticed there are a lot of run has admin problems.. I think its trying to remove or gain access to a file which it does not have permission to get .
Is there anyway to fix this? Am I missing something in my coding?
As you said in your question, you don't have write access that file.
Either skip files you don't have access to, or run the application as admin.
There appears to be a limitiation with the win32 api that will skip all files in the folder if you do not have access to one of them.
Check out this solution from Microsoft Connect:
How to: Iterate Through a Directory Tree (C# Programming Guide)
Solution:
A bit of tracing showed the CommunicationException was being thrown because there was an issue with my exception T not serializing correctly; because, two layers deep, I had an anonymously typed object, which was unserializable. Removing it and bubbling up the changes appeared to fix it. There was somethinge else small I did before that, but I can't remember for the life of me what it was, only that it wasn't done in the config.
I was getting messages from my traces such as:
Type 'RebuiltWCFService.Requests.HelloWorldRequest' with data contract name 'HelloWorldRequest:http://schemas.datacontract.org/2004/07/RebuiltWCFService.Requests' is not expected.
Consider using a DataContractResolver or add any types not known statically to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding them to the list of known types passed to DataContractSerializer.
Original post
I've encountered a seemingly strange issue today that I just cant't find an answer to!
The problem: my service is throwing a CommunicationException when I throw a FaultException! It does not do this if I don't throw an exception.
In my service, I'm properly defining the fault contracts:
[OperationContract]
[FaultContract(typeof(Faults.HelloWorldFault))]
Responses.HelloWorldResponse HelloWorld(Requests.HelloWorldRequest parameter);
Then under error conditions I'm throwing an exception of the correct type:
if (_errors.Count() > 0)
{
Faults.HelloWorldFault fault = new Faults.HelloWorldFault(_errors);
throw new FaultException<Faults.HelloWorldFault>(fault, new FaultReason("There are one or more errors in the request. Check the 'Errors' property for more detaisl"));
}
And then I'm catching it on the client end:
try
{
response = client.HelloWorld(new BasicService.HelloWorldRequest() { Number = 49 });
client.Close();
Console.WriteLine(String.Format("Response message: {0}, Response number: {1}", response.Message, response.Number));
}
catch (FaultException<BasicService.HelloWorldFault> ex)
{
...
}
That all seems OK to me, and like it should work. However, as soon as I go to test my error clauses (by providing bad data, such as a missing field), the whole thing dies on me. When I throw my FaultException, the service instead throws a CommunicationException with the message
An error occurred while receiving the HTTP response to http://localhost:8732/Design_Time_Addresses/RebuiltWCFService/Service1/.
This could be due to the service endpoint binding not using the HTTP protocol.
This could also be due to an HTTP request context being aborted by the server (possibly due to the service shutting down).
See server logs for more details.
Can anybody offer some insight on this one? I am using the basicHttp binding, and I've also tried it with wsHttp. I will post my config file upon request.
A FaultException is a child of CommunicationException. So there is nothing wrong in what's happening in your code.
If you are uncertain about what the exception is while handling, it is usually reported as CommunicationException. If you want to handle your specific exception in your own way, use the following structure.
try
{ ... }
catch (FaultException<MyDemoException> me)
{ ... }
catch (FaultException fe)
{ ... }
catch (CommunicationException ce)
{ ... }
catch (Exception ex)
{ ... }
In the above structure, Exception is parent of CommunicationException. CommunicationException is the parent of FaultException and so on.
System.Object
System.Exception
System.SystemException
System.ServiceModel.CommunicationException
System.ServiceModel.FaultException
System.ServiceModel.FaultException<TDetail>
System.ServiceModel.Web.WebFaultException<T>
Thanks guys, you helped me to understand the issue in a better way. My observation: I kept a List MyData - to hold any generic/dynamic collection, that was unable to serialize, so resulting to close the connection, so the communication exception.
When I removed the List from Fault Contract, and throw Fault style, it was clearly giving Fault contract exception, instead of communication exception.
Hope it helps,
HydTechie.
I ran into this problem because I had one or more breakpoints in the wrong place. I removed all breakpoints with Debug..Delete all Breakpoints (Ctrl-Alt-F9), and all of the CommunicationException exceptions disappeared and were replaced with the correct messages coming back.
Yes, the timeout is 60 seconds, so this never should have occurred, so it was probably some weird artifact of Visual Studio 2012.