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Hi,
Yesterday I ran into the exception mentioned in the title. In the mean time I have found a solution for it but I wonder why it happened, why the solution works and most importantly if someone else has run in to this sort of problem as well.
Below are some declarations and a few lines of code. The two lines of code are located in two separate functions: one to send an XML formatted message and one to receive the XML formatted response. The Write operation sends a 74 byte data block to the server. The Read operation receives a 105 byte data block sent back from the server to the client.
When I first tested the software I got the Exception mentioned in the title and it simply did not work. Using WireShark I could clearly see that both data blocks were sent back and forth as expected but on trying to read the supplied answer I always got the exception.
I finally managed to solve it by introducing a 20 millisecond delay before executing the Read operation whereas originally both operations executed very fast after each other, presumably well under a millisecond.
That makes me suspect that the problem is caused by calling the Read operation while the earlier Write operation is still ongoing in the background.
Both operations are asynchronous and I think it is quite possible that although the Write operation immediately returns there may very well be some ongoing background activity related to it so that when the Read operation is performed too fast it interferes and the Exception occurs.
Any thoughts, comments, remarks or bits of enlightenment would be very much appreciated.
Shared ClientSocket As System.Net.Sockets.TcpClient
Shared ClientStream As System.Net.Sockets.NetworkStream
ClientStream.Write(TxBuffer, 0, bytesToTx)
ClientStream.Read(RxBuffer, bytesRxed, RxBuffer.Length - bytesRxed)
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You should never do it like that. Reading messages from a remote device will fail if that device has not yet sent any data. You should either test the connection to see if data is waiting to be read, or use an event handler that gets called when the message arrives.
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Yes: excellent idea. If I check for DataAvailable first it will probably avoid the problem. I'll do some testing to see if it does.
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Thanks Richard, it was an excellent suggestion indeed. This works quite well now.
Do
If ClientStream.DataAvailable Then
bytesRxed = bytesRxed + ClientStream.Read(RxBuffer, bytesRxed, RxBuffer.Length - bytesRxed)
If IsStringInBuffer(XmlEndString, RxBuffer) = True Then
Return bytesRxed
End If
End If
System.Threading.Thread.Sleep(RxTimeout)
rxLoopCount += 1
Loop While rxLoopCount < MaxRxLoops
When the loop executes the first time it skips the Read operation because there is not any available data yet. 10 milliseconds later ( RxTimeout ) there is and it all works.
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Error in exporting SHEET2
code to populate datagrid:
'For x = 0 To ds.Tables.Count - 1
' Dim tp As New TabPage("TabPage" & x)
' TabControl1.TabPages.Add(tp)
' DataGridView(x) = New DataGridView
' 'Dim tabPagex As System.Windows.Forms.TabPage
' tp.Controls.Add(DataGridView(x))
' DataGridView(x).DataSource = ds.Tables(x)
' DataGridView(x).Dock = DockStyle.Fill
'Next
Export to excel：
Dim xlApp, xlBook, xlSheet As Object
xlApp = CreateObject("Excel.Application")
xlBook = xlApp.Workbooks.Add
xlSheet = xlBook.Worksheets()
xlApp.Visible = True
xlSheet = xlBook.Sheets("sheet1")
Dim Cols As Integer
For Cols = 1 To DataGridView1.Columns.Count
xlApp.Cells(1, Cols) = DataGridView1.Columns(Cols - 1).HeaderText
Next
Dim i As Integer
For i = 0 To DataGridView1.RowCount - 1
Dim j As Integer
For j = 0 To DataGridView1.ColumnCount - 1
If Me.DataGridView1(j, i).Value Is System.DBNull.Value Then
xlApp.Cells(i = 2, j = 1) = ""
Else
xlApp.Cells(i + 2, j + 1) = DataGridView1(j, i).Value.ToString
End If
Next
Next
xlApp.Sheets.Add(xlApp.Sheets("sheet1"))
xlApp.Sheets("sheet2").Select()
For Cols = 1 To DataGridView2.Columns.Count
xlApp.Cells(1, Cols) = DataGridView2.Columns(Cols - 1).HeaderText
Next
For i = 0 To DataGridView2.RowCount - 1
Dim j As Integer
For j = 0 To DataGridView2.ColumnCount - 1
If Me.DataGridView2(j, i).Value Is System.DBNull.Value Then
xlApp.Cells(i = 2, j = 1) = ""
Else
xlApp.Cells(i + 2, j + 1) = DataGridView2(j, i).Value.ToString
End If
Next
Next
xlApp.Sheets.Add(xlApp.Sheets("sheet2"))
xlApp.Sheets("sheet3").Select()
For Cols = 1 To DataGridView3.Columns.Count
xlApp.Cells(1, Cols) = DataGridView3.Columns(Cols - 1).HeaderText
Next
For i = 0 To DataGridView3.RowCount - 1
Dim j As Integer
For j = 0 To DataGridView3.ColumnCount - 1
If Me.DataGridView3(j, i).Value Is System.DBNull.Value Then
xlApp.Cells(i = 2, j = 1) = ""
Else
xlApp.Cells(i + 2, j + 1) = DataGridView3(j, i).Value.ToString
End If
Next
Next
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What error, and where does it occur? And why is the code that is supposed to populate the datagrid all commented out?
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This code uses TabControl loop to add TabPage and DGV, and then exports them all to excel.
Terminate and report error when generating SHEET2,"system.NullReferenceException:The object reference is not set to the case of the object"
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The only way to find out which variable is causing the exception is to step through the code with the debugger. When the exception occurs you can look back in the stack trace to see why.
I suspect this may be your problem.
xlApp.Sheets.Add(xlApp.Sheets("sheet2"))
xlApp.Sheets("sheet3").Select()
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Dear all,
Hope you can help me out, i am new to VB scripting and i get the question from a customer to help them out with there VB script, They have the script below that is working fine on a windows 7 + Office 2013 computer but now they are migrated to a Windows 10 device with Office 365 and the script is stoped working.
It is a VB script in Excel/Access that can save the selected e-mail in outlook to a *.msg file:
<pre>Sub SlaMailOp()
Dim olApp As Outlook.Application, olNs As Namespace, Item As Object, eFldr As Object
Dim MailItem As Variant
Dim Onderwerp As String
On Error GoTo ErrorHandler
Set olApp = GetObject(, "Outlook.Application")
tmpOpenTextInvoer = "C:\temp\OpenTextInvoer"
If olApp Is Nothing Then
Set olApp = CreateObject("Outlook.Application")
End If
Set olNs = olApp.GetNamespace("MAPI")
Set eFldr = olNs.Application.ActiveExplorer.Selection
For Each MailItem In eFldr
If Dir(tmpOpenTextInvoer, vbDirectory) = "" Then
MkDir tmpOpenTextInvoer
End If
Onderwerp = PasGeldigheidBestandsnaamAan(Left(MailItem.Subject, 120)) & "_" & Format(Now, "YYMMDDHHMMSS")
MailItem.SaveAs tmpOpenTextInvoer & "\" & Onderwerp & ".msg"
Next
Set olApp = Nothing
Set olNs = Nothing
Set eFldr = Nothing
Exit Sub
ErrorHandler:
MsgBox "Er is een fout opgetreden bij het ophalen van de e-mail informatie! Is Outlook wel opgestart?" & vbCr & Err.Description, vbCritical
End Sub
Function PasGeldigheidBestandsnaamAan(Naam As String)
Naam = Replace(Naam, ":", "_")
Naam = Replace(Naam, "\", "_")
Naam = Replace(Naam, "/", "_")
Naam = Replace(Naam, "*", "_")
Naam = Replace(Naam, "?", "_")
Naam = Replace(Naam, "<", "_")
Naam = Replace(Naam, ">", "_")
Naam = Replace(Naam, "|", "_")
Naam = Replace(Naam, """", "_")
Naam = Replace(Naam, " ", "_")
Naam = Replace(Naam, "€", "EUR")
Naam = Replace(Naam, """, "")
Naam = Replace(Naam, "
Naam = Replace(Naam, "’", "")
Naam = Replace(Naam, "Ë", "E")
Naam = Replace(Naam, "ë", "e")
Naam = Replace(Naam, "Ö", "O")
Naam = Replace(Naam, "ö", "o")
Naam = Replace(Naam, "Ü", "U")
Naam = Replace(Naam, "ü", "u")
Naam = Replace(Naam, "@", "_AT_")
Naam = Replace(Naam, "#", "_")
Naam = Replace(Naam, "___", "_")
Naam = Replace(Naam, "__", "_")
PasGeldigheidBestandsnaamAan = Naam
End Function
Function Ampersand(Naam As String)
Ampersand = Replace(Naam, "&", "&")
End Function
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And?
What does it do that it didn't used to, or not do that it did?
Where does it do that?
What have you tried to find out where and why it fails? What happened?
Are there any messages?
What have you tried?
Where are you stuck?
What help do you need?
Remember that we can't see your screen, access your HDD, or read your mind - we only get exactly what you type to work with. We can't even run your code under the same conditions you do as we have no access to your systems or the sheet it's a part of...
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!
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sorry, users are getting the error:
application-defined or object-defined error
What is should do is save the selected e-mail in outlook to a folder (*.msg)
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At the risk of repeating myself, what have you done to find out where and why?
What has the debugger shown you?
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!
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If i run the debug it give me the error after the step:
MailItem.SaveAs tmpOpenTextInvoer & "\" & Onderwerp & ".msg"
This is the last step where it should save the email in the folder,
For the test is renamed the folder "OpenTextInvoer" and the script did create the folder after i run it for the first time so in my opinion the autorizations are fine.
Please i am sorry if it sounds really amateurish but i am really new with vb scripting and trying really hard to understand it..
If you have any arguments about things that i need to test please feel free to say me so
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So us eteh debugger and put a breakpoint on that line. Then start looking at what the variables contain, and so what you pass to the SaveAs function. Then check that path and make sure it exists and can be written to by the user.
We can't do any of that for you - finding and fixing script bugs is just the same process as you use in application debugging!
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!
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thanks! i understand,
if i breakpoint the SaveAs function and go/point over the "tmpOpenTextInvoer" i see the folder where it needs to be saved so and that is OK.. if i point over the part "Onderwerk" (Onderwerp is Dutch for Subject) i see the subject from the e-mail that i selecteed in outlook. so that part is working fine
i did remove the folder and run the script and the script created the folder like it should be and for the test i put "everyone" on the group with full access but same error is there...
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So you need to look at all the data in MailItem, and check that you can write a file with that name to that folder manually (i.e. not using SaveAs, but using the same filename).
It may be worth setting up an "all users full access" folder and trying to write your file to that under a "nondescript name": "MySafeFolder\AAA.txt" perhaps.
One of the major changes between Win7 and Win10 is a tightening up of security over the file system, and it's possible that the user that the SaveAs is running under (which is conceivably not the same as your user ID) doesn't have the right permissions over the folder.
But this is speculation - this needs carefully thinking about on the actual system(s) it's failing on, and we have no access to that!
Good luck!
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!
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I have a Listbox with items. Some reports are limited to 1 item, and others are limited to 24 items.
Say a report limited to 24 items is selected, and the user chooses 200 items. The event seems to fires 17 times, incrementing the selectedItems count 1 a time. So my MessageBox fires 17 times.
I really only need to fire the MessageBox once. Is there a way to wait for the last event in queue to cycle and then I run my code in the event?
[Edit]
From reading even more, seems to be no cure and I should can the message box, and replace it with a huge label in red that states the message.
If it ain't broke don't fix it
Discover my world at jkirkerx.com
modified 24-Oct-19 14:00pm.
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Is there a way to keep the event from firing? No.
Is there a way to "wait for the queued events"? No.
You're making the mistake of showing a message box on every firing of SelectionChanged. Don't do that, though, you can managed a list of items based on the changing of the selection.
You have to give the users some other way to signify they are done selecting items, like clicking a button.
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Thanks for the validation on "NO"
I get it now. Perhaps that is reserved for diagnostics and troubleshooting.
I just made a warning label in red, and attached a timer to it for 15 secs.
I'll get fancier and make a panel with the label and show/center it in the screen.
If it ain't broke don't fix it
Discover my world at jkirkerx.com
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How do I create a program that will make the video conferencing and still have chat rooms?
Work under a multi-user network without the Internet.
thanks
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You're not going to get a direct answer to such a broad question.
"How" is going to be understanding the problem and all the sub problems that make it up, such as interacting with cameras, video clients, transferring data over TCP and UDP, writing what amounts to a media server, ... and there's LOTS and LOTS of problems to solve that make up those problems.
Frankly, this is a huge undertaking and if you're even asking this question, you're not ready to tackle it.
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Good afternoon. I have an issue with a stepper motor where I need to control it via an RS232 connection. The motor and control board are very old (circa 1993) and they came with code in Basic language meant to control the motor. I am trying to use that code in the Vintage BASIC interpretor available online, but I'm getting an error code telling me there is an unexpected end of the file. Is there anywhere I can go to debug a simple BASIC program and try and find out where the error is coming from? This, unfortunately, is not something I do (I don't really have any coding experience, at least not since I was very young). The code is pretty short, it's only 90 lines long, so there really isn't all that much to check.
Thanks to anyone who might be able to help.
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Which implementation of Basic was it designed for? There's a few dialects out there, each with subtle differences in syntax. If you post a fragment, someone here might recognize it 
Bastard Programmer from Hell 
If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
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We used to get unexpected end of file errors in some old MSBasic (MS-DOS days - I really am old!!).
This usually tracked down to a non-visible character embedded in a line of source code which displayed as a space. It was a pain to track down - couldn't use any search because we didn't know what we were searching for.
In the end we spotted the errant lines by using TYPE filename.BAS - these days you would do that in a command window (still can't stop myself calling it a dos box though). Then we just overtyped that line.
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Hello!
What is the code to force Windows to refresh the display settings? I have a VB .NET Forms application that has been steadily updated long enough that it has moved through multiple .NET versions and deployed across Windows XP, Windows 7, and now Windows 10 (we were able to avoid Vista and 8).
Now, on Windows 10 running on an HP, I have a display problem. The problem in the HP, but there is a work around that I would like to trigger from the application.
To fix the problem, after launching the app (from DEV or EXE):
1) Dock / Undock (switching between native and attached displays)
2) Open display settings and change something (resolution, scale, etc.)
3) Perform some other, similar display adjustment that requires the OS to update all of the resolution/scaling constants.
In each case, when change the display or display settings, the problem is resolved, and when I change back, things continue to work fine. It also does not matter if I start on the laptop display or the attached displays. I can duplicate the behavior and fix on multiple HPs running windows 10.
What I need is code to force Windows to refresh the display settings.
Background: The problem is clearly in the OS, likely the display driver. However, HP has been having issues with display drivers ever since the rush to market with the Thunderbolt and they have yet to fix most of those problems. HP blames Microsoft, Microsoft blames HP, nothing gets fixed.
Using app level functions, such as Refresh, and PerformAutoScale do not do the trick. The problem appears to be that windows is reporting different values to the application on container size, and usable size. The app initially draws the controls to the correct container size, but then only repaints a smaller usable size.
Making the window smaller (reducing the container size to below the apparent usable size) and then bigger again, does not make the problem go away - there is a fixed "usable size" that the app will not repaint beyond the borders of, even when the container goes beyond that size. What is interesting about this is that the app will update the data in the controls beyond this "usable size" - it just doesn't properly repaint, instead it adds the new text on top of the old text. It also leaves behind the drawn window edges as the container is sized larger.
Another interesting tidbit is that I can run the app, perform the work around to "fix" the problem, and then close the app. Upon reopening the app, the problem returns, and the work around is again required.
Please help with both a code driven work around, or even better, an OS level fix.
The particulars:
1) VB .NET in Visual Studio 2017 (version 15.9.16)
2) Windows 10 (up to date per Microsoft)
3) HP ZBook Mobile Workstation "Bang & Olufsen" with i7, lots of memory (has no problem with Solid Works 2017)
4) Display drivers for both laptop internal, and Thunderbolt dock external up to date
5) Behavior duplicated on second HP (same config) with Windows 10; same app continues to run just peachy on second HO (same config) running Windows 7.
Todd
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