.NET SyncLock Order Deadlock?
Sep 7, 2010If I have two Synclocks
synclock a
synclock b
end synclock
[code].....
ADVERTISEMENT
Invoke Within SyncLock Causes Deadlock
Apr 13, 2011I was wondering if this is known / expected behavior. By design?Is it documented somewhere?
My 'real' code does need something to keep one thread from accessing a listview while another is busy clearing and refreshing the Items collection, so it's not as easy as omitting the synclock section in the example below (The SyncLock in my case is on the ListView).
This code, which can be pasted over a new empty form's user code class, deadlocks during the Invoke call. It doesn't reach the entry point of SetText (setting a brakpoint there, the deadlock occurs before the breakpoint is hit).[cod]e...
C# - MultiThreading And Deadlock?
Mar 28, 2009In which situations we can do the multithreading and deadlock concepts. can give some examples
View 4 RepliesHang/deadlock In MSJET40.dll?
Jan 17, 2012I have a VB.NET GUI (VS2005) that calls into a VB6 DLL to query MSAccess 2003 databases using DAO 3.6. Yes, I know this is not an ideal scenario, but that's the way the current application is set up. Component Checker shows MDAC 2.8 SP1 is installed. This application usually runs for a long time on our customer's Windows XP SP3 system with no issues. Occasionally (read: after 11 minutes or 11 hours or days), we experience a hang in the application, such that it needs to be ended with task manager and restarted. According to crash dumps and one lucky capture within the debugger, all threads are waiting on objects/critical sections within ntdll.dll. My specific thread gets stuck there and comes from MSJet40.dll. In the crash dumps, most threads are stuck in NTWaitForSingleObject, RtlEnterCriticalSection, etc.
I've been troubleshooting this intermittent issue for months and am convinced this is a bug in MSJet40.dll. The version of the DLL is 4.0.9511 and I see there is a hotfix for 4.0.9514 on XP SP3 outlined in: =[URL] I would like to get this hotfix to see if it fixes the issue and speak with MS if it doesn't. I have crash dumps and procmon traces of these events. This sounds very similar to the dreaded "Jet Bug" that shows up on a Google, supposedly fixed for Windows 2003 Server SP1, but I see no mention of it on Windows XP SP3.
C# - Use The Multithreading Concepts And Deadlock Concept?
Mar 27, 2009I will connect with one database from several machines. In all machines they need to insert the data in single table. In that time: how to use multithreading and deadlock concepts? Using the MySQL database and also MS Access.
View 2 RepliesWebClient And Locked XML File (deadlock Error)?
Jan 19, 2010Quote:
System.Exception: Transaction (Process ID xx) was deadlocked on lock resources with another process and has been chosen as the deadlock victim.
I suspect this
Dim webc As New WebClient
webc.DownloadFile(remotexml, targetxml)
webc.Dispose()
Then i am using the targetxml right after that:
Dim xmldoc As New XmlDocument
xmldoc.Load(targetxml)
etc.
It seems that xml file is locked by the first process (WebClient).
Asp.net - Detecting/preventing Error/deadlock When Opening/reading Text File?
Dec 21, 2009I am reading file with text contents on it.sample dictionary.txt contents:
aa
abaca
abroad
apple
Snippet A:
Dim path as String = Server.MapPath("dictionary.txt");
Dim dictionary() as String = {}
Try
[code]....
Basically, I want to make sure that I can handle/prevent this error.Does Snippet B, solves the problem, if not is there other way so that I can prevent this error.BTW, this a web application and I am expecting multiple users.
Using SyncLock And Monitor Together?
Sep 15, 2010I was just wondering if mixing SyncLock blocks and Monitor.Enter/Exit statements is dangerous. I know SyncLock uses Monitor and a Try block in the background, but are there any problems with using the two together for thread synchronization?
View 1 Replies.net - How To SyncLock A Shared Integer
May 28, 2012I am pretty new to multi-threading in general and I would like to know how can I lock a shared integer variable to not be accessed by other threads while it is read/updated by an other thread.When I try do do SyncLock myInteger, I get that error : Error 6 'SyncLock' operand cannot be of type 'Integer' because 'Integer' is not a reference type.
Here a simplified example of what I mean
Private Shared myInteger As Integer
Private Sub MySub()
SyncLock myInteger ' This does not work
' read/write a new value to myInteger
End SyncLock
End Sub
MySub is called by multiple instances of the class, and running in multiple threads?
.net - SyncLock On Null Object
Mar 25, 2011Is there simple way to SyncLock an object that can be null? And before you ask for it, yes, I know that it isn't logical to perform a SyncLock on a null variable. However, that would simplify my code because right now, I have no choice but to perform a null check all over the place before calling a SyncLock.
[Code]...
Safe To Use A Synclock On The Serialport?
Aug 3, 2009I have an application that requires several threads, otherwise the main UI thread would end up frozen.i am after a little advice as i have not really don alot of threaded applications.
First Question;
I have a thread which handles data coming in from the serial port( this wil become much more complicated), is it safe to use a synclock on the serialport object : -
[code]...
SyncLock On Write - Read - Or Both?
Jan 7, 2011Suppose I have a byte array, Private Data as Byte(). This array is private within a class. The class provides public functions for reading and writing to Data. This class can be accessed by multiple threads, so I want to avoid a situation where reading from it and writing from it don't happen at the same time.
For now, I am using SyncLock to avoid issues. Can I put SyncLock Data in just the write functions, or does it need to be in the read functions? Or, both? I don't have a specific code example in mind. I am just curious if there is any benefit to locking for both read and write functions if the writing functions' SyncLock will make writing have exclusive access to it in the first place.
VS 2008 SyncLock A DataTable?
Oct 24, 2009I'm trying to SyncLock my DataTable, to avoid problems with multithreading and stuff. But it doesn't seems to work. I'm trying to lock a DataTable wich is acceseed inside a nested for-loop:
vb.net
SyncLock radiolopere
For Each row As DataRowView In tableview
[code].....
.net - Using SyncLock To Synchronize Access To List(of T)?
Nov 16, 2010I have a class that contains a List(of T) used in a multithreaded application. I have three methods Get, Add and Remove where these access and modify the List(of T). I was using SyncLock to lock m_List any time I queried it for the desired object as well as when I added or removed objects. However I'm curious as to if there is a performance gain by simply locking m_List when I add an object or remove an object as opposed to when I'm searching for a desired object?
[Code]...
List Of Objects - How Does SyncLock Works
Apr 22, 2011I have a List of objects shared by multiple threads, it sometimes generate IndexOutOfRangeException when trying to Clear. While searching for solution I found that I should use SyncLock while accessing the List. But my question if what is the importance of lockObject in SyncLock block
E.g. while clearing myList
Can I use
Synclock myList
myList.Clear
End SyncLock
or lockObject should be different from myList?
What I think about sysnclock is "lock is obtained for object specified as lockObject". What if I specify list to be cleared as lockObject, shouldn't the compiler supposed to obtain the exclusive access to list before clearing it ?
Multi-threading With SyncLock And Invoke?
Mar 5, 2009Once again Invoke has come back to haunt me! I have an application that has some background threads, serial communications and obviously a GUI. Now, the serial ports received incoming messages as events and these get processed and incoming data is logged both to a file and also appended to a RTB in the GUI (done using Invoke if InvokeRequired is true).Now, under normal circumstances everything is super happy and runs quite nicely but when stressed I reach some sort of deadlock.
What happens is I have two methods AddOutput and RemoveOutput. These both sync over an object SyncOutput As Object. When messages are received on the serial port they are processed and depending on whether or not a response is required AddOutput is called. This adds out going messages to a dictionary which is then accessed by a thread and the messages are sent out. If an acknowledgement message is received then the corresponding message in the dictionary is removed.
[Code]...
SyncLock Required Before If Statement Or For Loop?
Oct 2, 2009If completedOrders.Count <> 0 Then
For i = 0 To completedOrders.Count - 1
SyncLock completedOrders
'Do some work, for example this:
Dim text As String = completedOrders(0).getCN & " " & completedOrders(0).getDeviceName & " "
End SyncLock
Next
End If
Is a synclock needed before the if statement or for loop? In other words. When you call methods like .length or .count is it necessary to synclock them or can another thread be writing to it at the same time. CompletedOrders is a generic list of a class.
VS 2010 Use SyncLock On Function On Each Thread?
Sep 8, 2011Ok so I coded this app that generates a number/word and it will upload to my database. Speed wasn't the issue when my db was under 1million entry. Now that I got about 100million entry it takes a few mins to upload.I worked with threading before but now I want all my threads to access this function that will give them a string. Now here is the problem, if 2 or more thread access the function at the same time, it will crash.How can I by pass that?I read about SyncLock. Can I use SyncLock on my function on each thread?
View 1 RepliesNeed To Change One Combo Box (of Many) To Order Items In Descending Order
Nov 1, 2009I have a combo box bound to a datasource. I need to change one combo box (of many) to order the items in descending order.I'm guessing I could order the collection in the dataset, but that will mean all my combo boxes will be reordered?
View 2 RepliesRe Order Column Order In A Data Bound DataGridView?
Apr 17, 2010I have a databound Datagridview. The DGV is bound to a datatable of a strongly typed DataSet created using the wizard. Is there any way to re order the columns before displaying them eg: the Columns are displayed in the DGV in this other Col4, Col6, Col3, Col1,Col5, Col2
But I want to it to show as Col1, Col2, col3, Col4, Col5, Col6?
I realise that the display order followed the Column order in the database table and by extension, the datatable. I have re-arranged the columns in the Database but the Datatable still retains the old order.
Put Frequent File I/O Operations Within A SyncLock Block?
Sep 14, 2009Say I have some code that does this:
Public Function AppendToLogFile(ByVal s As String) As Boolean
Dim success As Boolean = True
Dim fs As IO.FileStream = Nothing
[Code].....
First of all: is it a problem that I have that Try/Catch/Finally block inside of a SyncLock?
Second of all: suppose this code runs, on an event, potentially many times within a small timeframe--say, ten times in one second. Is it OK to have it SyncLock like this, or would it make more sense to have it add a line to a Queue, and then write all the lines from the Queue to the file on a timer that goes off, say, every second?
Skip A Code Block When Synclock Is Active?
Nov 3, 2009Is it possible to skip a code block when a synclock is active?
For instance:
A object of class Bicycle is used by thread 1 and has a synclock on it.
Then thread 2 comes along and needs to know if the lights of the bike are working. But if there is a synclock active then thread 2 just forgets about checking the lights and goes to make a delicious chocolate pie.
IDE :: Crash VS2010 IDE By Mixing Lambda Expressions With SyncLock?
Jun 30, 2011Can someone who is using a 64 bit machine help me pintpoint this crash to either the VS2010 IDE itself or one of the plugins I have installed?
It's the code fragment below. When I copy & paste it into the Main() function of a new VB.Net console app on my Win7 64 bit machine, the VS IDE crashes and dies onthe spot, every time I try it.
Doing exactly the same on a 32 bit XP machine, nothing abnormal happens.
The 64 bit machine does have some IDE plug-ins installed, the biggest of which is DevExpress (the free version), so i think either one of those or the fact that the IDE is running on 64 bit must be the culprit.
This is the code. The static variable can also be made a module-level variable, with the same result.
Synclock A Section Of Code While Waiting For ShowDialog To Return?
Jun 1, 2010I'm having trouble working out how to lock my application out of a section of code while it waits for a response from an external program've used Synclock on a section of code with the Me object in the expression. In this Synclock I call an overridden ShowDialog method of a dialog box, which has a timeout parameter, but does return the value from the underlying ShowDialog function call ,once the timer is setup. Works like this.
SyncLock Me
Dim frmDlgWithTimeout As New frmDlgWithTimeout ' dialog box with overridden ShowDialog '
Dim res As DialogResult = frmDlgWithTimeout.ShowDialog(10 * 1000) ' 10 sec timeout '
[code]....
VB - Multithreading With Synclock - Threads With Different Sessions Run Trylock Simultaneously
Jan 31, 2011i have some test code which i run at every load of a page in my asp.net website [Code] the "dotrace" simply add a record to a log table in the db. now the right result would be that i should have the entries in the db in order "entered","exiting","exited" but actually when i look in the db i see first 2 "entered" then 2 "exiting" etc. meaning that the multi-threading is working ok, but not the synclock. is that correct?
and how can this be fixed? the real code will be adding records to the db and might be called from several pages of different sessions, but the same code must not run twice concurrently. if i open multiple pages at once, they still clash some times. but if i'm correct, the issue is now not with the synclock as much as with the httpruntime.cache, because when using a standard property, on one page, the code works 100%. so how can i make sure that 2 threads, even from totally different sessions never run the trylock simultaneously?
VS 2010 : Access ORDER BY To Get DESCENDING Order
Oct 8, 2011This might not be so 'VB' as it is 'SQL using VB' I have an application with a built in MS Access DB. I have a table that has a column full of integers, I shoot the DB a SQL "order by 'column name' " string and it returns the table ordered by my column of integers.BUT it returns them like this, and I want them like this
0 6
1 5
2 4
[code]....
How do I get the OrderBY to do a descending list starting with the highest number?
VS 2010 Tab Index Order And Control Order
Aug 18, 2011I'm working on the exercise page 73 (VB 2010 in 24 hours). It's basically a form with 2 text boxes, 2 text labels and a command button. It's really simple and uses this loop to cycle through the items, and tell me the name of them in a Messagebox
[Code]...
[2005] SyncLock And Multithreading - Public Class Utilities With A Many Shared Functions
Feb 11, 2009I am trying to get a handle on SyncLock and multithreading, but I am having some trouble wrapping my head around exactly how it should be implemented. I have a Public Class Utilities with a many Shared Functions. I want to make sure that each function can only be executed when there are no other concurrent calls to the same function. So If I have 2 functions, A and B in a Public Class Utilities, what is the syntax so that a function "locks" while it is being executed, preventing any subsequent calls until the "locking" thread has completed?
CODE
Public Class Utilities
Public Shared Function A (ByRef i As Integer) As Integer
[CODE].............................
I know I need to wrap the statements of execution in a SyncLock block, but I am unsure of the scope of the parameter used with SyncLock...is it private to the function, class, etc? Can the same object be used to lock both functions if they are independent?
Synclock Doesn't Prevent Sharing Errors When Multiple Threads Access Same File
Apr 14, 2010I am using Synclock to prevent multiple threads from logging text messages to the same file at the same time, but this doesn't seem to work:I get frequent sharing errors on the logfile, within the synclock block.The Synclock is using the variable holding the filename, because it exists all the time and because it is always the same object, whatever class instance or thread I'm in.[code]Despite using Synclock and a Using block around the code, I keep getting this error in the sw.WriteLine(Msg) line:System.IO.IOException: The process cannot access the file '(filename)' because it is being used by another process.Should I use some other type of object than a string to synchronize on?I cannot use a user interface object (button or so) because it is a windows service project.It was written and compiled in Visual Studio 2008, but targeting the 2.0 framework because it has to be able to run on some old Win2000 machines.
View 12 RepliesVS 2008 ORDER BY That Does Not Order Correctly?
Jan 14, 2010I have to order a table following a logical order but I cannot find the appropriate ORDER BY clause.To simplify I have 2 fields field1 and field2
1 record : field1 contains �2� and field2 contains �1�
2 record : field1 contains �1� and field2 contains �2�
3 record : field1 contains �2� and field2 contains �2�
[code].....