NullReferenceException In .NET After Upgrade To 4.0?
Jul 25, 2011
I have a VB.NET solution that I just upgraded. It was originally in .NET 1.1, I upgraded to .NET 2.0 and verified that it would build and run correctly. Then I upgraded from 2.0 to 4.0. It is still building with no errors, but when I try to run I am getting a NullReferenceException in Global.asax.vb. The really weird thing is, the line that is throwing the exception is this:
Dim dt As System.Data.DataTable I am not trying to use the variable, just declare it. Further down a Function is called that returns a DataTable and sets the variable, but I don't even get to that line. It is throwing the NullReferenceException on the Dim line. Has anyone run across this before? Is this some issue with upgrading?
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I did a Rebuild Solution before posting. This is a web application and the only files I see in the bin folder are the dll files I am referencing. I'm not sure what else I should clean up.
I have written an address book and for its database, I used Access to create a .mdb database and store my data programmatically into this .mdb file.However, the problem is that when reading and saving data to this kind of database I have to use Jet 4.0 which is NOT available on 64-bit systems and I have to compile my application as 32-bit in order to run on all systems.I just want to know how is upgrade to SQL?I never used SQL, can I create a stand-alone database file using SQL like Access and create tables/fields so I can modify it programmatically?I also need the database file to be independent and don't need any special requirements to run on target systems, like the .mdb file I've created in Access!
Possible Duplicate: Best Strategy for moving from VB6 to .NET Conversion tool comparisons for visual basic 6.0 Is there a good tool anyone can recommend to convert a commercial VB6 application into a VB.NET application. I have discovered some free ones and some commercial one's, but can't find any reviews and opinions of developers who have tried and failed or tried and succeeded.
What are the complexities involved? I know that .NET uses managed code and multi threaded apartments etc whereas VB6 is based on COM.
My website is VB.NET 2.0. I already opened a it in VS2k8 and told it not to upgrade. Now I want to upgrade, how do I trigger it? All the posts say 'just open it in 2k8 and it will prompt you'. Well I did, and it did, and I didn't want to yet. Now I cant get it to come up.
I bought a script vbulletin for install it in my forum, now I have a discuzx forum on [url]...forum.php but I don't like this script. I trying to change my app from discuzx to vbulletin, I using this app for send pms to my members. The application is almost finished. only the last thing I need is that I can not fill the message. I still I have no forum installed and I am testing my app with another forum and I can not insert the message.[code]...
I'm having trouble upgrading this vb6 code to vb.net.
Code: Option Explicit Private Declare Function FloodFill Lib "gdi32" (ByVal hdc As Long, ByVal X As Long, ByVal Y As Long, ByVal crcolor As Long) As Long Private Type Point
I've given a VisualBasic Software, written in VB5. Now the whole thing should run under Windows 7, so it needs to be converted to VB8 or VB9. It seems that most of the API of VB changed a lot in these years, so for me it seems quite impossible to run just a few code upgrades and everything is fine...
The biggest Problem are Forms. There are a lot of Forms in this Software, which are declared inside .frm files and begin always like this:
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It seems for me that this Stuff was generated with an UI-Layouter, so none self written code is in there.Is it possible to run this code in VB8/9 or even rewrite it that VB8/9 understands it? I'm currently very pesimistic and think that the whole software needs to rewritten...
I am trying to get my conversion fixed from a VB6 application over to a VB.net 2010 application. Everything went well but for a few sleeted listbox NewIndex and OLE control.
Below are the trouble lines that could not seem to be converted:
I've written a VB.Net program and it's deployed all across the U.S. When I make changes or bug fixes and want to get a new version out to my clients, I'm wondering if there is an automated way of upgrading the clients. I cannot use Click-Once deployment, I have over 7,000 users and want to control the upgrade through a program. Is there a tool in the toolbox for automating this process?
In VB6, I used the INet control, is there an equivelent to this in .Net?
I have been supporting vb.net application which worked fine with office 2003 but when one of my client upgraded to the office 2007.then we got a error like this after a bit of research ,i found that
"One possibility is that the file is corrupt (Access databases have a tendency to do that -- see
Article #2190 for a way to compact / repair the database through code). A more common reason is that you are trying to connect to an Access 97 database with Access 2000 or better drivers, or vice-versa. Make sure the server has the most recent MDAC (MDAC Download Page) and the most recent JET drivers (see Article #2342). Also, try upgrading your database to a more recent format (Access 2000 or better)."
may be my case is similar.the applicattion is working fine with the other users ,only the user who upgraded to office has got the problem.
I have a windows forms program that I upgraded from VB 2005 to VB2010. When the program was on VB 2005 the form would resize to any monitor resolution. But since I upgraded the program to VB 2010 some of my controls are off the screen when I run my program on a 1024 x 768 screen resolution. Why is it doing that?
I got a new laptop friday, it has windows 7 and its a 64 bit system. I installed visual studio 08. everything was fine until I opened one of my projects.Seems like the powerpacks drawing items no longer exist, there is only a pointer and reort viewer in the group now and all of the items that I have used in the past are keep my app from running.
I used to write programs in Quick Basic on my XP computer. I now have a Vista (64bit) computer and everybody knows (except me) that those programs won't run on my Vista computer.I want to be able to write single user programs on my Vista computer like I did with my XP computer. Since I'm somewhat familiar with the Quick Basic language, I want to stay in the "Basic" language family. What do I need to have on my Vista computer that would allow me to write and run simple single user programs?
I have a big application which is really working succesfully written in VB.Net version 2005 I am wanting to upgrade this to VS2008/2010 early next year. All versions used would be the fully paid for versions
I am totally clueless about what this upgrade would entail. I cannot afford to re-write the entire application as it is critical to our business.Can I take my code across without too much hassle? And then slowly "re-write" the code to take full use of the new features. Would i need to attend some sort of "new features" course? Or is the accompanying documentation good enough to get by.
I know that VS 2003, 2005 and 2008 had the VB6 to VB.NET Upgrade Wizard. Now, on a email list I'm on a said that he cannot open a .vbp file to use the upgrade wizard in VB 2010. Is there no Upgrade Wizard in VB 2010?
I've had 2008 express on this PC since it came out -- I basically have ONE important project that now is being troublesome.
Just had an "unhandled exception" and "configuration system failed" -- errors I've never received before and I've just made minor changes to the program.
For one, I was thinking about a fresh install of 2010 express (but remember some real problems when I upgraded from 2005, so ??) be afraid ? very afraid?
ALSO --
What are the mandatory files I need to save in a project folder?
If I delete the bin and obj folders (plus?) and let it write new ones will that sometimes cure some problems?
What is a good way to SAFELY keep all your hard work but get rid of possible clutter and ?
In VB6 I have drawn lines on a picturebox and if I display another form the lines remain (I haven't drawn them in the paint event).In vb2008 doing the same the display is erased when another form is displayed.How can I reproduce the vb6 functionality in vb2008?
I have an old VB6 project converted into VB2008 express. It contains a datagrid control called AxMSDataGridLib.AxDataGrid. This is probably legacy control from previous VB versions, am I right?
The application reads data to this grid using ADO and it works most of the time. It is supposed to be read only but I cannot parametrize it correctly and sometimes when I exit the application I get an exception. Now, I seriously lack skills of this IDE and .net framework since I don't know how to get more info about the exception. The exception is just a messagebox saying something like "Key column invalid or not sufficient. Update changed too many columns". This exception comes from this datagrid.
Now, since there's a high probability that this is an old control and I cannot get the exception handled, I was thinking to upgrade it to .net DataGridView. Does anyone know if upgrading this old AxDataGrid to .net DataGridView is possible and how to do it?
I am abit afraid to just delete the old control and replace it with new since the application works and I am not attached to any source control (for reverting changes). Maybe it's possible to make a copy of this project with another name and safely play with it?
I am upgrading a program from VB6to VB2010.Is there no upgrade wizard for this?When I tried to upgrade to VB2008 I got a message ole_e_cant_bindtosource. Looking online the two suggestions on changing the registry didn't work so I thought I would go straight to VB2010.
We have a number of classic ASP websites using a VB6 DLL (COM) object for their functionality in the standard way. The DLL is regsvr32'd and the pages use Server.CreateObject to create an instance of the necessary object in the DLL, which in turn triggers the OnStartPage function of the object being created, passing in the ScriptingContext which we then use to get Request(querystring, form) information, read/update session information and read/write cookie information (etc). For clarification, the way you update/store a cookie value using ScriptingContext is
objSC.Response.Cookies(Key) = Value
In preperation of doing a complete .Net overhaul on the code base (and as a first step), we ran the code through the .Net 2008 VB upgrade tool, which makes a few minor code changes, sets up references to interop libraries (for ADODB, ASPTypeLibrary, CDO, etc) and adds the necessary attributes to allow the .Net object to be exposed to COM, and after a few tweaks here and there guided by comments (todos) left by the upgrade tool, the code is compilable except for anything that tried to update/store a cookie using the above code as now, through the ASPTypeLibrary (Interop), the Response.Cookies collection is readonly (with no obvious way to write a cookie now).
If I comment out the offending line of code, the code compiles, and all I need to do is register this new .Net DLL (and it's interop DLLs) in the GAC, use regasm to register it through COM and the classic ASP sites continue working as if nothing happened (except for writing cookies), using Server.CreateObject to create what it thinks is a COM object, triggering the call to OnStartPage, passing in the ScriptingContext.So although the code base is "upgraded" to .Net it is using a lot of interop libraries to continues working as before, including using the ASPTypeLibrary.ScriptingContext object, as this is what the classic ASP pipeline exposes. how to write/store a cookie in this scenario?
Scenario: I have about 14000 word documents that need to be converted from "Microsoft Word 97 - 2003 Document" to "Microsoft Word Document". In other words upgraded to 2010 format (.docx).
Question: Is there an easy way to do this using API's or something? Note: I've only been able to find a microsoft program that converts the documents to .docx but they still open in compatability mode. It would be nice if they could just be converted to the new format. Same functionality you get when you open an old document and it gives you the option to convert it.[URL]..EDIT2: This is my current function for converting the documents
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Also it opens word after about 2 or 3 conversions and starts flashing but keeps converting.EDIT3: Tweaked to code above a little bit and it runs cleaner. Takes 1min10sec to convert 8 files though. Considering I have 14000 I need to convert this method will take a reasonably long time.
EDIT4: Changed the code up again. Uses a threadpool now. Seems to run a bit faster. Still need to run on a better computer to convert all the documents. Or do them slowly by folder. Can anyone think of any other way to optimize this?
I am running Windows 7 eval. copy and have been for months. It's great. I saw that the Beta on Visual Studios 2010 and decided to make the jump from Visual Studios 6. I watched all the MS videos on upgrading from VBP to Net and downloaded all of the upgrade programs and advisors. The programs I need to migrate require only minor changes. The video shows Visual Studios 2005 upgrading a VB6 Project because the upgrade wizard intercepts the open and upgrades the file. There are several problems:
1. It appears the VS2010 and VB2010 do not have this capability
2. Running Windows 7, VS2005 and the Associated framework will not load correctly
3.VB2005 does not load correctly
4.The upgrade msi will not load because the specified framework version is not loaded. Apparently it does not recognize Framework 4.
5. So I cannot migrate my VB6 programs to NET using VS/VB 2010. My only solution is to build up another system with XP and do the migration on that system.
So my basic question is do I have to build another system or is there something I am missing about VS2010? Does it have the capability to migrate VB6 programs like VS2005?
