FieldAccessException When Class Accesses Its Own Field (.NET Project Upgraded From 3.5 To 4.0)?
Aug 6, 2010
I have a VB.NET solution, just upgraded from 3.5 to 4.0. One of the classes has a private field:
Private _Projection As ICalculatedPath.At runtime, any time the class containing that field accesses that field, I get a FieldAccessException. The first time that field happens to get accessed is a null check in a method, and one of the things I randomly tried is changing the above line to:
Private _Projection As ICalculatedPath = Nothing.When I do this, I get the FieldAccessException on that line saying that the class's .ctor() cannot access that field. I've also tried making the field protected and public, clean/rebuild solution, restarting VS, targeting x86 and .NET 4.0 specifically on every project in the solution, and other non-sensical measures to get rid of this Exception but to no avail. This code worked fine before the upgrade, of course.
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Feb 24, 2012
If I put this piece of code in a new fresh vb.net form, add a button and two labels and start debug I get execution time of about 11.5s.If I put the same piece of code in a new form in an old project upgraded from an earlier version of vb.net, start debug I get an execution time of 7.5s.So I do exactly the same in the two projects but get different execution times.
What do I have to do with the fresh new project to get the same execution time ?I am not interested in improving the code to be able to calculate primes faster. I just want to know what is the significant difference between an old upgraded project and a new fresh one. I am using windows 7 64bit on a 2,4 Ghz Intel quadcore.
Public Class Form2
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Dim l, h, p As Integer
[code]....
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Jul 21, 2009
I upgraded my project to VB 2008 and in the designing window, everything looks new and updated. When I run the program, however, it appears to look the same old way it looked in the old VB I upgraded it from. Is there something I can do to make it appear the new way during run time?
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May 13, 2010
Why upgrading my project from 05 to 08 would stop it from working on any new computer. It will install fine on my computer and users that currently have it installed. I assume it's the crystal prereq issues. It always fails with crystal errors now on install. The prereq's are checked in the properties.
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Jan 7, 2009
I am about to commence coding (actually recoding) on a project that accesses 100 tables of a database, more to added at later time. About half of the accesses are queries with joins and unions. I am more of a coder to not use wizards such tableAdapter, but code more by other methods. I have read some post of this site that suggest avoiding tableAdapters, not to use them in an Enterprise environmentl, but no reasons. I would like to hear from willing to bend my ear, pro or con.
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May 9, 2012
can someone please help me with a textbox? I have created a new class and require this textbox field within a sub in the new class but i get Error1 'TextBox1' is not declared. It may be inaccessible due to its protection level.I have tried MyClass.TextBox1 = Form1.TextBox1 but I get declaration expected.
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Jun 23, 2009
I am redesigning an application that I have previously written which accesses an SQL database, pulls records, creates an object hierarchy based on a bunch of custom classes that I created, and displays them in a TreeView control. When the user selects a node, a tabbed page displays the information about the object underlying the TreeNode selected.
I have since begun experimenting with Databinding to my Objects as I have recently redigned the objects to communicate directly with the datarow that each object is based on instead of storing the values in a private variable thus:
[Code]...
Allowing the databinding management objects to do the heavy lifting of getting the values, displaying them in the controls and writing new values as needed back to the objects (and thus the DataSet) i think is preferable. How can I accomplish this? I have added the Objects as datasources to the DataSources window, added the objects elements to the tabbed pages. How do I bind those controls to the item that is specified by selecting the TreeNode?
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Mar 9, 2010
i have a program that accesses an access database but i have a problem with this line
-'dbSkillCommand.Fill(dsSkillPageData, "skill")'giving this error message
-'No value given for one or more required parameters.' [code]
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Dec 14, 2010
After upgrading my solution with both c# and vb.net projects I have encountered some problems:
1. When for example writing Public Property MaxDate As Date and pressing enter it does not create the Get/Set values
2. Refactoring is not available
3. The properties window is blank when viewing classes (normally I would see Serializable and COM properties to the right)Intellisense works and the above problems work in new projects.
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Sep 6, 2011
Public Sub theConnection()
Try
conString = "DSN=XXXXX;UID=XXXX;PWD=XXXXX;DATABASE=XXXXX"
con = New OdbcConnection(conString)
Catch
MessageBox.Show("Connection to the Spec Database was not made")
[Code]...
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Dec 9, 2010
There are problems installing an application developed in VB6 that accesses SQL Server on Windows 7?
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Sep 16, 2011
I have a VB Function (in Visual Studio 2008 with .NET 3.5) that opens up a connection to an Oracle database and queries the database for information. Apparently after some trial and error, I discovered when the SQL statement is being processed and filling the dataset, it apparently is taking up too much memory trying to complete the task. I'm running into System.OutofMemory exceptions and other unpleasantness.I'm wondering, is there some sort of program out there to measure memory consumption of your SQL code that is being processed in a Visual Studio application?
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Aug 25, 2009
I have a VB Function (in Visual Studio 2008 with .NET 3.5) that opens up a connection to an Oracle database and queries the database for information. Apparently after some trial and error, I discovered when the SQL statement is being processed and filling the dataset, it apparently is taking up too much memory trying to complete the task.I'm running into System.OutofMemory exceptions and other unpleasantness.I'm wondering, is there some sort of program out there to measure memory consumption of your SQL code that is being processed in a Visual Studio application?
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Jul 26, 2010
I recently upgraded to Crystal Reports 2008 for the barcoding functionality. When we use the barcode in the report designer, it renders as expected, so we installed the Crystal Reports 2008 redistributable package on our dev server to test deployment, but we receive the error message listed below. I cannot locate any information about this issue on the business objects site, or azaleas site, or any info regarding deployment of barcoding functionality.
[Code]....
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Jan 11, 2012
I have got a class which contains more then 160 fields. i need the name of fields (not value) in an array. get loop through names for field or get list of field names in a array so that i can loop over it and use it in code. i am using visual studio 2010
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Jul 23, 2010
I have an ASP.NET web site project where I am using both VB.Net and C# class files. I have included separate sub folders in the App_Code directory for classes of each language.However, while I can successfully make use of a C# class in a VB class, I cannot do the opposite: use a a VB class in a C# class.
[Code]...
I get an error that "the type or namespace "VBTestClass" could not be found". What am I missing here?
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Apr 1, 2012
[Code]...
Is there an explanation for this limitation? I mean, it's still in the constructor for the object, and the base class constructor is still executed first.
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Jul 26, 2011
I have a class, MyClass, declared as public, with a Shared method test():
[Code]...
If I comment out Response.Write MyClass.test(), everything works fine and I can use the Class - however, trying to access the Shared method, I get the following error: Local variable 'myClass' cannot be referred to before it is declared Any pointers as to what I am doing wrong?
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Feb 13, 2012
I have an 8 bit digital output board used for device controlling. Each external device needs one bit and is controlled by a different application.I have written a class library and the class DigitalOutputPort (VB 2010) that envelopes the driver that manages the 8 bit port. Each device application uses this class, creating its own instance.
In order to set a bit of the digital output port, I have to write a byte to that port: this byte is the bit mask for all 8 bits together: to set HIGH the bit number 0 - 1 - 2, I have to write 7 on the port, to set HIGH all 8 bits, I have to write 256, and so on...
All works fine when only ONE application uses the class. But if two applications want to set its own bit on that port, I get problems because I do not know the current value of all bits set by other applications (the driver has not such function) and, of course, I cannot change one bit without changing all the other (if I do not know the current bit mask)
Normally this looks like a typical case of sharing data between two application and my first idea was to write the current value of the port in a file on the disc, where all application can access and read it. But it seems to be too much heavy for this simple problem. Moreover it could also creates performance ans reliability problem.
Then I though about using a shared field (property) in the class. A shared field preserves its value between all instances of a class: but is it also true between instances from different applications? I cannot find more info about this last point, I have to make same test.
A third way would be that I create just only ONE instance of the class DigitalOutputPort, one for all applications.The first application that needs it, create the object, all other applications will used the already created object.I like more than other this way, but I do not know if and how it can be done.
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Mar 18, 2010
I have written a multithreaded crawler and the process is simply creating threads and having them access a list of urls to crawl. They then access the urls and parse the html content. All this seems to work fine. Now when I need to write to tables in a database is when I experience issues. I have 2 declared arraylists that will contain the content each thread parse. The first arraylist is simply the rss feed links and the other arraylist contains the different posts. I then use a for each loop to iterate one while sequentially incrementing the other and writing to the database. My problem is that each time a new thread accesses one of the lists the content is changed and this affects the iteration. I tried using nested loops but it did not work before and this works fine using a single thread.
Here is my
SyncLock dlock
For Each rsslink As String In finallinks
postlink = finalposts.Item(i)
[CODE]...
Finallinks and finalposts are the two arraylists. I did not include the rest of the code which shows the threads working but this is the essential part where my error occurs which is basically here postlink = finalposts.Item(i) i = i + 1
ERROR: index was out of range. Must be non-negative and less than the size of the collection. Parameter name:index
I tried copying it to a new list but dosent work.
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Mar 21, 2012
I have a class (using a class rather than a structure only because I can set a default field value for the fields I declare in the class) and I'm using a web service that returns information (demographic information) in JSON. I am using LINQ to get the values of each "entry" from the returned list and in that, I have to parse through and pull out the actual data that I want.Here's how I have it doing right now (just a start, there are 44 of them total, thus my question which will follow the code):
Dim returnedStats = From ljo As Linq.JObject In returnedObject.SelectToken("results")
'
'
For Each stat As Linq.JObject In returnedStats
[code]....
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Apr 5, 2012
I have a standard "class library" project with a set of classes that I use to import in almost all my new projects.
The way I work is creating a new Solution with an empty project, which is my main project, and then I add to the solution the mentioned class library project, this way I can see both projects in the Soluction Explorer and even see the library code or update it if needed. Then I write the code in my main project and I compile.
This lead me to have 2 files when I compile: file *.exe and stdlib.dll
Some cases I use the lib for very small tools that I want to redistribute in a easy and clean why, so I would like to embed the stdlib.dll generated from my class library project into my *.exe file.
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Dec 20, 2011
I have a class that exposes an auto implemented property Enabled
[Code]...
But If I had not use an auto implemented property and declared my own backing-field as follows this is accessible from the subclass: Private _Enabled as Boolean ---- EDIT ----
The abve line is incorrect - this is not possible, it was in fact Protected in the original code which allowed access from the sub class See @JonSkeet answer ---- EDIT Of course I can just access Enabled from the sub class to work around this but can someone explain why this is the behaviour?
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Jun 20, 2011
In a number of my projects, I find myself declaring a rather boring class:
[Code]...
to e.g. allow an object to give information to another object in such a way that the information can be mutated later wherever it goes. For example, in a Dictionary(Of String, Holder(Of SomeImmutableType)) it's possible to update the thing of SomeImmutableType without having to change the Dictionary itself (since the Dictionary's entry for a given key will always contain the same Holder object, that Holder object may be used as a lock).
[Code]...
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Aug 25, 2010
When I add my vb classes to my C# project in vs 2008 they are readily available to be used in my c# classes. But for some reason 2010 can't see them. I could be missing something simple but i couldn't make it work in the past hour.
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Sep 15, 2009
how can I add a class of a different project to my current project as a reference?I tried Right click_-> add existing item --> ( The class from the other project) then it gives me error.I am not sure how can I use that class as my reference to my current project?
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Jun 27, 2009
I found what i was looking for on this old thread but I don't know exactly what to do woth it. The code given by Tall Dude seems to compile fine except for two errors..
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Jul 28, 2011
For extra credit I need to create a project for my class. I am here asking what is some of your ideas on a project I already did a calculator and I don't know what else to do one one
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Jun 21, 2010
Create a project that contains a Pet class. Each object will contain pet name, animal type, breed and color. The form should contain text boxes to enter the information for the pets. A button or menu item should display the pet information on a separate form. Hint: Use a ReadOnly property on the input form to pass the object to the second form.
What I have done so far is create a new class with the name Pet and have instantiated each object with readonly property. I have also created another form where the information entered by the user will be displayed. Guess I kinda need to know what would be the next step? And I want to ensure what I have done so far is correct.
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Dec 11, 2011
I would like to use the below VB.Net class in my C# Project. [code]...
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