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Implementing locking is probably the last resort of a bad design.
Think about it. A client locks a row, then loses network connectivity. The row is still locked, and the client that locked the row can't unlock it. Now what do you do? The rest of your clients that still do have connectivity are screwed until that row or table is unlocked.
You may want to read up on all of your options before doing something so drastic. Google for "Access database concurrency".
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Most developers ignore this problem, last in has the power is the general rule. There are so many different scenarios that can be envisaged that to try and deal with them will very quickly have you biting you're own arse.
Make sure it is a real world problem not something thought up by a manager trying to cover all bases. I have often responded to this requirement with 'if we get a race condition then I'll deal with it otherwise let me do something productive'. Then when they insist do an estimate of the cost and performance hit!
Never underestimate the power of human stupidity
RAH
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Here's a possible solution...
You can implement your own locking mechanism simply by having a lock table. (this way you can have an editable table that, in case the client loses connectivity, another user can go to the administrator edit screen and clear the lock, if necessary)
tblLocks: TableName , IDNum, LockedBy
(primary key: TableName,IDNum)
when the edit is about to take place, try adding a record with the table/id/username
if you get an error, that record for that table is locked. otherwise leave that entry there until they quit or save and exit. then delete the record.
The LockedBy field is not necessary, but then you can see who has it locked, if you so desire.
Just use the windows login name or if your software has a login, use that.
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How to convert an SQL table to Access table in vb6 .
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This question is wrong in so many ways... 
Open up Access, and link or import the table using ODBC.
My advice is free, and you may get what you paid for.
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I'm trying to get all messages using MAPI in VB.NET
(I'm using Eudora same as Outlook)
I search in Internet but all I found is Sending Email
(Acctually its not sending it only opens the Eudora and fields(subject, to, note))
or other type of MAPI I'm using AxMAPIMessages
(what I mean is in MAPI theres a field/function sample(Getmessages),
In AxMAPIMessages theres no function as shown in MAPI)
modified on Saturday, June 4, 2011 4:00 AM
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Hi,
When I try the following I get an error....
crReport.DataSourceConnections(servername, database, True)
"Property access must assign to the property or use it's value"
I am trying to assign a database to my crystal report. The reason being I have a test database and a live database.
Any ideas where I am going wrong or what I should do?
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I have no idea what you're doing, but DataSourceConnections is a read-only property that returns a collection of IConnectionInfo objects.
You cannot assign annything to that property and you definitely can't call it as if it was a method, like your code is doing.
I don't use CrystalReports, but perhaps you're looking to do something like:
crReport.DataSourceConnections.Add(...)
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Hi!
Is there a way to use "function handles in VB 2010"?
For instance, let's suppose to define an array of sub or functions:
array1 = {sub1(), sub2(param1, param2), sub3(param3)....}
I would like them to be called in the sequence specified within array1 from another sub, let's say a "server sub"
for i = 0 to N_MAX
INVOKE_FuNCTION(array1(i))
end
Lines before were in "symbolic" language (not true VB, of course).
Is there a way to build array1 and to subsequently call the therein contained functions, as stated above?
Thanks!
...............................................
For who is interested in my troubles....
I am using the System.Windows.Form.WebBrowser and I have a sequence of operation to perform programmatically, each of which requires the DocumentCompleted event to be triggered. My idea was to put the for loop within the function DocumentCompleted function, in order to call the operations being sure the web page is loaded. This allows the sequence of function to be changed. tnx!
Do While ReadyStatus = False
Loop
ReadyStatus = False
End Sub
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Sure. "Function pointers" as you called them are Delegates in .NET.
Read this[^].
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I have a code for displaying all files inside a folder in a FTP Server,
but I don't know how to view a folder inside of a FTP Server or
inside an another folder.
Here's the code to display a file inside a folder
reqFTP = DirectCast(WebRequest.Create("ftp://ftp.microsoft.com/"), FtpWebRequest)
reqFTP.Method = WebRequestMethods.Ftp.ListDirectoryDetails
reqFTP.Credentials = New NetworkCredential(UserID, Password)
response = DirectCast(reqFTP.GetResponse(), FtpWebResponse)
Dim responseStream As Stream = response.GetResponseStream()
Dim reader As New StreamReader(responseStream)
Dim CrLf As Char() = {Constants.vbCr, Constants.vbLf}
Dim lines() As String = reader.ReadToEnd().Split(CrLf, StringSplitOptions.RemoveEmptyEntries)
Dim lineArr() As String
For i As Integer = 0 To UBound(lines)
lineArr = Split(lines(i))
lstFTPfiles.Items.Add(lineArr(UBound(lineArr)))
Next
responseStream.Close()
response.Close()
reader.Close()
Example in ftp://ftp.microsoft.com/
In root directory it has a sub folders
Folder1
Folder2
I want to put that two sub folders in a ListBox.
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According to several hits found with Google, the LIST and NLIST FTP commands return information on files and folders all together. You need to look at the details, and for a folder call LIST or NLIST recursively.
Here[^] is a CP article that does things similar to what you want, it is in C#, look for file "Program.cs"
Luc Pattyn [My Articles] Nil Volentibus Arduum
The quality and detail of your question reflects on the effectiveness of the help you are likely to get. Please use <PRE> tags for code snippets, they improve readability. CP Vanity has been updated to V2.3
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yah your right all files and DIRs will be shown when getting the list in FTP, actually my problem is not in my code, in my sample FTP Server. I choose a FTP location that has files only(ftp://ftp.microsoft.com/bussys/mspress/Excel2000/), but when I try it to root location in FTP Server all files and folders appear, my problem is so simple actually. 
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Long time ago I sent raw ZPL via the comm port. Now I would like to print to Zebra's shared off the same server.
It needs to be a two way communication: request the Zebra status - and then download the raw ZPL to print the label.
I've never used the TCP/IP classes. If anyone could point me in the right direction, I'd appreciate it.
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If the Zebra printers are in a Windows environment, then have the network administrator setup a printer queue and your application can send its output to that queue. Let the print server determine if the printer is ready or not.
Would this work for you ?
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I haven't done a lot of interfacing to windows printers - have used mainly 3rd party reporting tools.
Here's what I envisioned:
Table descriptive printer name and IP address - for picklist
No printer driver required to be installed - these are all Zebra printers, but some are different models
Connect to printer
Send ~H1 - read status command to Zebra
Wait for response - make sure ready, has correct label size, has ribbon. (these printers could be in another building - so I have to know if they're ready)
Send raw ZPL to printer.
Done!
Does your print queue idea provide for this?
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I spoke with one of the guys I work with and he has used a component from the following company to interface his applications to our Zebra printers.
Scroll down on the web page and look for "Raw Data Printer Component"
Maybe this will work for you.
http://www.vbgold.com/[^]
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Looks like that might work.
Could you ask your friend if it's bi-directional.
Thanks!
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My colleague does not use it for 2 way communication, so we cannot confirm or deny whether this functionality is available. However, it may not be necessary. Our approach is to just "send" the label data (ZPL code). The printer has its own print-server logic in it so that if a label is currently being printed it will cause the second label to queue up and wait.
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Thanks for the info and the followup!
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Can any one teach how to a SQL Stored procedure in vb.net 2008 ? 
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I have vs2005. Someone put together a project for us in vb6, but
when I try to open in vs2005, it converts, but doesnt compile and
I dont really see the source code.
I have projects in vc6 and those will convert to vs2005.
Does vc6 exist? Is there a way of downloading it?
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