Concurrency Control With Serializable Isolation Level?
Jun 28, 2011
I have to handle concurrency control and I used SqlClient.SqlTransaction with IsolationLevel.Serializable level. In that transaction, I do 3 works:
1. Select the latest updated time from a record of a table
2. Compare the latest updated time with a stored time paramater
3. If the result form comparision is "same" I will update that record
But my problem is, when 2 transactions is run at almost the same time.
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May 3, 2011
I have a VB.net CF app connecting to a SQL 2008 server. I'm trying to implement transactions but when i break my code at the start of a transaction certain read queries cannot be done on the table. For instance selecting all records from the table where id <> 123 Won't return any values. But select * from stock will return all values except for the row I'm working on.
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Nov 29, 2010
I'm trying to create a custom control that contains a List(Of Panel). I quickly ran into an error about the base class Panel being nonserializable. So I created my own class that inherits from Panel and implemented the ISerializable interface. At the surface, everything appears to work, at least everything at design time. I don't know what would happen if I tried to run the application. Anyway, the errors occur when I try to open a file that contains my custom control. For example, I create a new Windows Form and add my custom control to it. I save the Form and close it.
Then I try to open the form and get the following error: Object of type 'MyTestApplication.SerializablePanel[]' cannot be converted to type 'MyTestApplication.SerializablePanel[]'.
I don't know what I'm doing wrong? I've opened the XML file to see what it's actually writing, and read the header notes about using binary base64 serialization. I think that's what I'm using, but I'm not sure.
Below is the code for the class SerializablePanel:
Imports System.Runtime.Serialization
Imports System.ComponentModel
<Serializable()> _
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Apr 14, 2010
i understand that web service creates its own sessions so thats no problem to multi-thread. but i am writing my results into the database and files. how to do i do my concurrency control for writing into file and database here, can i do it on my calling app which is a console app or i will have to do it in my web service. i am not returning anything to the calling app.
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Sep 8, 2010
The problem is, having converted from VS 2002 to VS 2008 the designer can't seem to handle the custom controls on "my" (not original designer) app. Any time I try to copy, in particular, the custom derived comboBox control I get this error initially:
Type 'Corporate.Controls.data.comboBox+comboBoxDataSource+Item' in Assembly Corporate.Controls, ... is not marked as serializable.
I chased this error down, marking classes Serializable and private variables therein as NonSerialized when they caused a problem (which might or might not be the smartest way to attack this problem...) but I've hit a brick wall. The most base corporate derived ComboBox class is:
Namespace Corporate.Controls
Public Class comboBox
Inherits System.Windows.Forms.ComboBox
...
End Class
It's unrealistic to post all of the relevant code (I believe). The short of it is:
System.Windows.Forms.ComboBox <- Corporate.Controls.comboBox <- Corporate.Controls.data.comboBox
I just kept backtracking through the errors.At this point I can't set System.Windows.Forms.ComboBox to Serializable. I've tried marking the Inherits System.Windows.Forms.ComboBox clause with <NonSerialized()> and while that doesn't cause a build error it doesn't seem to fix the designer-generated error in the other libraries when I go to actually add, copy or even delete the control in WYSIWYG. And that is the only reference to System.Windows.Forms.ComboBox in that (or any other) corporate library.
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Apr 4, 2011
I have a VB DLL, and i need to use it in VB.Net project , so that, in order to use this DLL in both projects without interfering each other, i have to make it's property "ISOLATED = TRUE" , but when I set this property
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Oct 14, 2011
I am making a windows service that will communicate with a local application through named pipes, and with a server through WCF webservice. So the application hosts the WCF service for the local application, and is a client for the webservices. When trying to run this as a service, the whole thing crashes. I have localized the problem to the "Session 0 Isolation" issue?
�If two-way interaction is required, use Windows Communication Foundation (WCF), .NET remoting, named pipes, or any other interprocess communication (IPC) mechanism (excluding window messages) to communicate across sessions. WCF and Remoting have a better security enforcement that will prompt the user (assuming UAC not shut-off) to elevate if needed. But I am not sure what they meen. As far as I know, i cannot create a windows service as WCF.
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Apr 4, 2011
I have a VB DLL, and i need to use it in VB.Net project , so that, in order to use this DLL in both projects without interfering each other, i have to make it's property "ISOLATED = TRUE" , but when I set this property to TRUE , the following ERROR appeared
Problem isolating COM reference 'HMS_Server': Registry key 'HKEY_CLASSES_ROOTCLSID{821ee06b-d656-4c63-ad24-0f4e5b916a8b}InProcServer32' is missing value '(Default)'. HMS_WF3
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Aug 5, 2010
I have a form with a panel on it (among other controls). I am trying to load picture boxes into the panel (in an attempt to make a star grid). Using the code below, I get a "Top-level control cannot be added to a control." error on the "Parent = Me.Panel7" line.
Searching for this error, I came across a solution to change the TopLevelControl property of the panel to FALSE....but I then get an error "TopLevelControl is read only".
Public Class frmMain
Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
LoadPictureBoxes()
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Feb 24, 2009
i a m using VB.NEt 2003, wat i did is , i tried to bring A FORM into a GroupBox Control by using handling method.Im using in VB 6 i got the expected output.but in .NET i m getting an error msg "cannot add a top level control to a control ". when i degug it comes from the line DirectCast(frmObject, Form).Parent = Me.gropboxso u please reply me ..
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Apr 11, 2009
I have 2 apps and i want to controll their sound levels externally. Ex. 1 app is sound player and another one is GPS soft. I need to detect that GPS sends sound bits to audio card and at that moment reduce the sound level of audio player application. I would assume that could be done through winAPI but im not 100% sure.
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Feb 5, 2011
how do i control the volume level that the speakers output?
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Dec 5, 2010
I am trying to find the current level of zoom in a webbrowser control. I know how to zoom but the same doesn't work for retrieving the current level of zoom. I am trying the following: VB.NET Syntax (Toggle Plain Text )
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May 6, 2009
What node property tells you if the node in question in a TreeView is the Root Node (i.e. highest parent level)? I want to be able to test a node (True/False) in a node event procedure.
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Apr 1, 2012
I am creating an Excel add-in written in VB.NET. I would like to bind KeyDown and KeyUp events to the spreadsheet to record when the user presses and releases the arrow keys while navigating the spreadsheetIdeally, these events would be built into Excel alongside the native SheetActivate and SheetSelectionChange events, for example. Alas, they are not.
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Mar 6, 2012
Public Class b
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
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while compiling it i got error like "top level controls can not be added to control"what to do?
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Apr 12, 2012
I have searched the web for code relating to changing the system volume, muting the system volume, and outputing the current level of the volume as an integer, using VB.NET.
All the code that I have found either doesn't work, or is very long.
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Mar 1, 2011
If I have a winform, may I know how can I control the zoom level of the font in theapplication (as well as the application window itself obviously) by using Ctrl + Mouse Scroll Wheel? I see there is a Delta in the Scroll Wheel event, but not sure how that works.Is there any code sample that I can look into?
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Jan 6, 2010
In Visual Basic 2008, there's two different ways that I know of to accomplish the same thing:The Dim on the member level:
Dim counter1 as integer = 0
Dim counter2 as integer = 180
Public Sub SampleSub1()
[code].....
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Mar 18, 2011
I have created a simple program which uses a two tier structure of SQL Tables.At the top level, one record holds the date of the activities and linked to it using its primary key as a foreign key, three subordinate tables hold time stamped records.The issue I have been unable to solve is that before adding any of the lower level records for a given date, a newly added top level record must be saved to the database.Doing this manually is simple - but can I rely on my users to remember to do this before they start plugging in the lower level data?I thought not, so I am looking to save the top level automatically.I've failed miserably but I refuse to believe that it's not possible.
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Feb 27, 2011
I have a class that is serializable. I would like to compute the MD5 of it. I already had a function in the project to get a MD5 from a Stream, so I reused it, and created a function to convert an object to a memorystream. The code is as follows. Does anyone see any problems, but more to the point, is there an easier way to do this that I'm simply missing?
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Jul 16, 2010
Question: I use a serializable dictionary class, found at , to serialize a dictionary.
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Jun 2, 2010
I've got a 'MyDataTable' class that inherits from System.Data.DataTable I've implemented ISerializable in my class and have a 'Public Overrides Sub GetObjectData...' But when I try to serialize the an object of 'MyDataTable' I get an error saying that 'MyDataTable' is not marked as serializable.
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Feb 12, 2011
I have multiple level of For Each and in each level, i have a Linq that is the 'In' criteria as in:
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It will go inside each for (because the value is not nothing), however, it will only loop (next) in the very inner 'For Each t In tFor'. After it is finish inner loops, the outer Fors' or Next will not execute... even thought there are more than one values in that 'In'... like 'sFor' or 'fFor'. i've noticed while debuging, while break at the for (for example 'sFor', before stepping in), i get the error message:
"Enumeration yielded no results" when i expand the result for that variable and it will not step into it. but if i do not expand the result, it will step in. It seem that some how, once an element is accessed for that 'In' collection, it breaks (meaning does not loop for the rest of the elements) the next for that collection is this a bug or am i missing something in Linq? BTW: i believe it has something to do with the SqlDataReader in the Linq. I'm working with IAsyncResult.
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May 29, 2009
I have the follow VB.NET class definition:<Serializable()> Partial Public Class Customers End Class
Inside another file I have the same thing (with different methods and variables of course). When I compile, I get the following error:Attribute 'SerializableAttribute' cannot be applied multiple times.The error is pretty self explanatory. My question is though, if I just mark the one class as Serializable(), can I assume the entire class with be marked as serializable()? In other words, Do I only need the serializable() tag in 1 spot in the class?
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Mar 22, 2012
Having to update somebody else's code. Did I do this correct for the code below?
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Apr 11, 2009
I have a class that contains a list of properties which serializes just fine. However I need one of those properties to contain a collection of another class to give me sub classes
Example XML
<VideoOptions>
<property1>value1</property1>
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Feb 17, 2010
I have a serializable class and structure I created for an ArrayList to be access within a Web Application. The problem I am having is the count comes back as zero after calling New. I debugged the code and the Arrylist is being populated
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Jul 10, 2011
ToSerializable is it possible instead of marking a Class with the <Serializable()> attribute?
as in the following Class.So you could maybe do:>>myObject.ToSerializable
<Serializable()> _Public Class ExampleClass
End Class
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Jul 16, 2009
I have no idea where to begin. I've looked online but haven't been able to find anything.
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