Hey all i am trying to get this code that worked in VB6 just fine to work in VB.net 2008. It doesnt seem to want to connect (but has no error after it goes past the sockMain.Connect().
sockMain.RemoteHost = "192.168.1.77"
sockMain.RemotePort = 77
sockMain.Connect()
Now when i do this:
On Error GoTo oops
sockMain.SendData(txtSend.Text)
oops:
If Err.Number = 40006 Then
MsgBox("It doesnt seem that the server is running. Please check it and try again")
End If
I get the It doesnt seem that the server is running. Please check it and try again. error.
What am i missing??
David
As I explained in a comment, VB.NET and VB 6 are almost entirely different programming languages. You're not doing yourself any favors by trying to write VB 6 code in VB.NET. There's no reason to migrate at all if you're not going to take advantage of the new features provided by the .NET platform.
Beyond the structured exception handling that I mentioned already, you should ditch the old WinSock control in favor of the classes found in the System.Net.Sockets namespace.
Try replacing what you have with something like the following code:
Dim tcpClient As New System.Net.Sockets.TcpClient()
tcpClient.Connect("192.168.1.77", 77)
Dim networkStream As NetworkStream = tcpClient.GetStream()
If networkStream.CanWrite And networkStream.CanRead Then
' Do a simple write.
Dim sendBytes As [Byte]() = Encoding.ASCII.GetBytes("Is anybody there")
networkStream.Write(sendBytes, 0, sendBytes.Length)
' Read the NetworkStream into a byte buffer.
Dim bytes(tcpClient.ReceiveBufferSize) As Byte
networkStream.Read(bytes, 0, CInt(tcpClient.ReceiveBufferSize))
' Output the data received from the host to the console.
Dim returnData As String = Encoding.ASCII.GetString(bytes)
Console.WriteLine(("Host returned: " + returnData))
Else
If Not networkStream.CanRead Then
Console.WriteLine("Cannot not write data to this stream. " &
"Please check the server and try again.")
tcpClient.Close()
Else
If Not networkStream.CanWrite Then
Console.WriteLine("Cannot read data from this stream. " &
"Please check the server and try again.")
tcpClient.Close()
End If
End If
End If
if you want the feeling of the vb6 winsock in .net world try this, beware it was not updated since 2008 and there is a few bug, look at the comment at the end of the acticle for more information
The Connect call can take a little while to complete. Even if your client has made the physical connection to the server, you have to give it a wee while to establish the TCP virtual circuit. If you put a breakpoint on the call to SendData and wait just a second or two, then continue, you'll probably find that it works OK.
Related
Dim cat As New Catalog()
Dim con As New OleDbConnection()
Dim cmd As New OleDbCommand
Dim ds1 As New DataSet
Dim conn As ADODB.Connection
' Open the Access database.
conn = New Connection
conn.ConnectionString =
"Provider=Microsoft.Jet.OLEDB.4.0;" &
"Data Source=" + openExcel + "\Test" + ".mdb; Persist Security Info=False"
con.ConnectionString =
"Provider=Microsoft.Jet.OLEDB.4.0;" &
"Data Source=" + openExcel + "\Test" + ".mdb; Persist Security Info=False"
conn.Open()
xlWorkSheet1.Columns(5).Insert
Dim cellValue As String = ""
Dim newValue As String = ""
Dim sh1 As String = ""
Dim qty As String = ""
Dim matchText As String = ""
Dim sql As String = ""
con.Open()
sh1 = LTrim$(xlWorkSheet1.Cells(i, 1).Text)
sql = "SELECT Num_ber, Q_ty FROM good WHERE Na_me LIKE 'staff%' And Ty_pe = 'ORD'"
Dim cmd As New OleDbCommand(sql, con)
Dim myReader As OleDbDataReader = cmd.ExecuteReader()
conn.Execute(sql)
myReader = cmd.ExecuteReader() ' HERE'S THE PROBLEM
xlWorkSheet1.Cells(1, 5) = myReader.GetString(0)
xlWorkSheet1.Cells(1, 11) = myReader.GetString(1)
myReader.Close()
conn.Close()
conn = Nothing
**I wanted to retrieve a specific value from mdb and then write it to excel.
Here's my code, I got this error so many times and I can't find it out. Can anybody help me? Thanks.**
[1]: https://i.stack.imgur.com/6Fuvg.png
Ok, you first have to decide when usng .net what "provider" you are going to use, AND THEN decide what kind of data objects you want to use.
You can use a oracle provider, a sql server provider, or in this case, since we using Access, then we can use EITHER oleDB, or ODBC. Either choice is fine. Most use oleDB providers for Access, but often ODBC is a good choice, especially if down the road you plane to swap out Access for say SQL server.
What the above means in plain English?
You don't want to adopt the external ADODB code and library. That code is NOT .net, and thus you REALLY but REALLY do not want to write your .net code that way. ADODB was written LONG before .net, and is what we call un-managed code (non .net). I strong, but strong suggest you do NOT add a reference to ADODB to your project, and I beyond strong recommend you avoid introduction of a non .net library for doing this!!! We certainly can adopt the oleDB provider in .net, but we will NOT have a direct reference to JET/ACE (the access database engine) in our applcation. As noted, there are some exceptions to this suggesting, but they don't apply to you and here.
Next up:
The design pattern in .net is to create the connection, get the data, and CLOSE the connection. This "pattern" will then be 100% sure that the data base is always closed, and you NEVER have to worry about if the connection is open, closed, or even if you forgot to close the connection!!! So, do this correct, and some "open" connection will never bite you, or will you have to worry about this issue.
You can in some operations keep the connection open for performance, but lets learn to walk before we run so to speak.
next up:
We certainly do NOT want to place and have connection strings all over in our code. Not only is this going to wear out your keyboard, but if you ever need to change the connection, then you going to have to hunt down all that code.
Best to let Visual Studio save that connection in ONE location, and MORE important MANAGE this for you!!!
Next up:
Do you ONLY need to work with mdb files, or do you plan/need to work with accDB files? This is a HUGE issue, and one that you cannot ignore.
next up:
Are you going to use the x32 bit version of the Access database system, or the x64 bit version?
Since your example posted code uses JET (access data engine for mdb files ONLY x32 bit version)?
Then this ALSO means you MUST (and I repeat MUST) force your .net project to run as x32 bits. You cannot use "any cpu", and you cannot use x64 bits, you MUST choose x86 bit size for your .net project. Failure to do so will result in the project not working.
Ok, with the above information?
First up, force/set/be 100% sure your project is set to run as x32 bits.
That setting is this one:
and remove the reference you have to ADO if you created one.
Ok,
next up:
Create the connection to the database.
Project ->properties.
This here:
And then:
and then
Now, you can browse, and select the access mdb file.
But, you MUST not skip the next step - you have to choose JET (older, mdb files), or choose the newer ACE (for accDB format files).
So, this:
now this:
As noted, you choose JET or ACE here.
now, we have this and you can use test connection.
BUT BE VERY careful!!!!
If you are using vs2022, then keep in mind vs2022 is the FIRST version of VS that is now x64 bits. As a result, vs can't pass the test connection!!! Your connection is in fact ok, but will fail with vs2022.
If you using a previous version of VS (before 2022), then the test connection button should work. and you see this:
Ok, now that we have a valid working conneciton setup, we can now write code, and we will NOT use ADODB!!!!
The typical code pattern to read and load a data table (like a access VBA recordset) will be like this:
Now, I became RATHER tired of writing that same using block over and over. So, in a global module, I have this code now:
Public Function MyRst(strSQL As String) As DataTable
Dim rstData As New DataTable
Using conn As New OleDbConnection(My.Settings.AccessDB)
Using cmdSQL As New OleDbCommand(strSQL, conn)
conn.Open()
rstData.Load(cmdSQL.ExecuteReader)
End Using
End Using
Return rstData
End Function
So, now with the above handy dandy helper routine?
Your code becomes this:
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim Sql As String =
"SELECT Num_ber, Q_ty FROM good WHERE Na_me LIKE 'staff%' And Ty_pe = 'ORD'"
Dim rstData As DataTable = MyRst(Sql)
Debug.Print("Na_me is " & rstData.Rows(0).Item("Na_me"))
End Sub
Or, display all return rows from that data table
Debug.Print("Na_me is " & rstData.Rows(0).Item("Na_me"))
For Each OneRow As DataRow In rstData.Rows
Debug.Print("na_me = " & OneRow("Na_me"))
Next
So, you really don't need (or want) a reader anyway. Just load the results into a nice clean, easy to use data table, and from that you can loop the table, grab rows, or do whatever you want.
My company posts invoices to both Ariba and Oracle Supplier Networks via HTTP POST. We've had an issue where we haven't been able to determine whether it's settings or code.
Below is the code:
Public Function SendMime(pFiles As List(Of String)) As String
'just use the text send option in HTTP connection
If pFiles.Count = 1 And pFiles.Item(0).EndsWith(".xml") Then
Return Send(My.Computer.FileSystem.ReadAllText(pFiles(0)))
End If
Dim Request As Net.HttpWebRequest
Request = DirectCast(Net.WebRequest.Create(GetFirstURL()), Net.HttpWebRequest)
Request.ContentType = "multipart/related;boundary=" & OuterBoundary & ";type=""text/xml"";start=""<" & _CID & ".1>"""
Request.Method = "Post"
Request.KeepAlive = True
WriteRequest(Request, pFiles)
Dim Response As Net.WebResponse
Try
Response = Request.GetResponse()
Dim ResponseStream As Stream = Response.GetResponseStream()
Dim ResponseReader As New StreamReader(ResponseStream)
Return ResponseReader.ReadToEnd()
Catch ex As System.Exception
Return "error: " & ex.Message
End Try
End Function
Private Sub WriteRequest(pRequest As Net.WebRequest, pFiles As List(Of String))
Dim PartCount As Integer = 1
_RequestStream = pRequest.GetRequestStream()
_tempStream = New FileStream("C:\lastMIMEsent.txt", FileMode.Create)
For Each File As String In pFiles
WriteBoundary(OuterBoundary)
If File.ToLower.EndsWith(".xml") Then
GetXMLPart(File, PartCount)
ElseIf File.ToLower.EndsWith(".pdf") Then
GetPDFPart(File, PartCount)
End If
PartCount += 1
Next
WriteTrailer(OuterBoundary)
_RequestStream.Close()
_tempStream.Flush()
_tempStream.Close()
End Sub
The send function is similar to the SendMime function, but with no attachments (cxml only). This code is shared between a Windows Service and a basic GUI test program.
edit: The error I get is: "Unable to connect to host."
Where things get weird:
On the server running the service: Oracle works, Ariba does not, when the service calls the SendMime function.
On the server running the service: Both work, when the GUI utility calls the SendMime function.
On my work station: both work, regardless of whether it is the service or GUI calling the SendMime function
My first thought was Proxy, but both machines are behind the same proxy.
My second thought was Firewall issues, but we disabled the firewall with no success.
We can connect to the address via web browser as well.
We tried with different Active Directory accounts, with no change as well.
Both the service and the GUI utility are running .Net 4.5 (needed for some asynchronous parts of the service). They were not at one point, but upgrading the Utility made no difference.
The only difference i can find, is that my machine runs Windows 7 and the server runs Windows Server R2, but I can find no documentation stating that there should be a difference.
I've been trying to figure this out for a couple weeks, experimenting with different adjustments, and at this point, both I and the server team are out of ideas. Any advice, whether its red flags in my code or just known windows server issues, would be greatly appreciated.
I have a program which runs on some wearable terminals in our warehouse. These terminals connect via remote desktop to our server which actually hosts and runs this program.
This program takes a scan of product, launches another program (if it isn't already running for the current user) which handles some processing, then does some additional processing once finished. One issue I'm running into is checking if the second program is already running. I've tried a lot of different code but this is what I settled on as it seemed to work perfectly fine.
Private Function CheckPrintLabelRunning() As Boolean
Dim selectQuery As String = "Select * From Win32_Process Where Name = 'vbPrintLabel.exe'"
Dim searcher As New System.Management.ManagementObjectSearcher(selectQuery)
Dim processList As System.Management.ManagementObjectCollection = searcher.[Get]()
For Each obj As System.Management.ManagementObject In processList
Dim argList As String() = New String() {String.Empty, String.Empty}
Dim returnVal As Integer = Convert.ToInt32(obj.InvokeMethod("GetOwner", argList))
If returnVal = 0 Then
If argList(0).ToString.ToUpper = Environment.UserName.ToUpper Then
Return True
End If
End If
Next
Return False
End Function
On Thursday, while the users were using the application on the terminals, the following error message popped up in my error logs. This application has seemingly been closing itself down, hitting the main form's FormClosing event (indicating that it isn't a full crash, but something that is handled inappropriately or an environment crash perhaps?). Here is the exception:
System.Management.ManagementException: Not found
at System.Management.ManagementException.ThrowWithExtendedInfo(ManagementStatus errorCode)
at System.Management.ManagementObject.InvokeMethod(String methodName, ManagementBaseObject inParameters, InvokeMethodOptions options)
at System.Management.ManagementObject.InvokeMethod(String methodName, Object[] args)
at vbFullCasePicking.frmFullCasePicking.CheckPrintLabelRunning()
at vbFullCasePicking.frmFullCasePicking.StartPrintLabelListener()
at vbFullCasePicking.frmFullCasePicking.PrintLabel(Boolean blnSMPLabels, String strCartonID)
I would like to point out that in this particular issue, the application did not close itself down, but I am still curious about this error as it's the first I've seen it of all the months this has been in use.
EDIT: More info...the server the application runs on is Windows Server 2003. This issue has not generated any event log entries of any kind as far as we can see.
EDIT 2: I completely forgot about this, but I have a previous question regarding this issue. I was initially querying all the processes which seemed to cause errors when multiple users would try to query at the same time. This is likely the same issue, then, just with a much smaller window. Any input is greatly appreciated.
Good Morning,
I have been tasked with writing a program that locates the local port a MAC Address is registered to, and to do that I need to SSH and Telnet into Cisco devices and receive the output of the commands so I can parse it and decide what to do with the information.
So far I have the SSH connection and parsing done no problem thanks to Renci.SshNET. But I am having trouble with the Telnet, I set it up to use Telnetlib.dll and I know it works because I can do "show users" on the switch I'm connecting to and see that one of the vty lines are being occupied by my application. But in the application I'm writing all I get is the application freezing up, none of the buttons work, and I can't see the mouse when I hover over the window, so I'm guessing that the application isn't liking something at run-time.
The code I'm using, in VB.NET is:
Using client As TcpClient = New TcpClient(host, 23)
Dim tel As TelnetStream = New TelnetStream(client.GetStream)
Dim buff(client.ReceiveBufferSize) As Byte
Dim result As String
tel.SetRemoteMode(TelnetOption.Echo, False)
Dim exp As Expector = New Expector(tel)
exp.Expect("username: ")
exp.SendLine(username)
exp.Expect("password: ")
exp.SendLine(password)
exp.Expect(">")
tel.Read(buff, 0, buff.Length)
result = System.Text.Encoding.ASCII.GetString(buff)
MessageBox.Show(result)
End Using
Telnetlib.dll include the definitions for the Expector, SendLine, Expect, and TelnetStream.
I did some debugging and found that it freezes when it goes to execute the result = System.Text.Encoding.ASCII.GetString(buff)
command.
Thanks for any help.
I seem to be receiving random error messages when trying to read queries from a SQLite DB stored on a network drive. On my development machine, I rarely ever get an error, but users are reporting random errors such as:
Unable to open database. File is encrypted or is not a database
Database disk image is malformed
Or it just doesn't return any data.
My code looks like such:
Private Sub LoadStoreCalls()
Dim tmpID As String
Dim QryString As String
Dim SQLconnect As New SQLite.SQLiteConnection()
SQLconnect.ConnectionString = "Data Source=" & SpiceWorksPath & ";New=False;Compress=True;Read Only=True;"
Try
'Open a connection to the database
SQLconnect.Open()
'Get StoreCode
tmpID = Mid(StoreCode, 2) & "-" & StoreName
QryString = "SELECT id, summary, status, c_location, c_store_device FROM tickets WHERE status = 'open' AND c_location = '" & tmpID & "'"
Dim ExQry As New SQLiteCommand(QryString, SQLconnect)
ExQry.CommandType = CommandType.Text
Dim da As New SQLiteDataAdapter(ExQry)
dasSpice.Clear()
da.Fill(dasSpice, "Calls")
SQLconnect.Close()
Catch ex As Exception
If SQLconnect.State = ConnectionState.Open Then SQLconnect.Close()
MsgBox(ex.Message)
End Try
End Sub
The problem is that my application relies on this data being returned to populate additional entries of a datagridview control, and because I cannot replicate this error on my development machine using debug, I cannot find where the fault is occurring.
If the user gets one of these errors, they usually keep trying to run the query and eventually it will work. Or they just exit my application and go back in and then it seems to work for a while. The errors are random and not always from running the same query.
I'm assuming it's due to an issue talking to an SQLite DB on a shared drive, but I can't find any information regarding setting timeouts. I also can't work out how to 'catch' the error because I can't replicate it myself. I have tried adding logging details to the Catch event handler, but it simply just returns me the error message (above) in the logs.
Any help would be greatly appreciated.
Thanks
After many hours of troubleshooting and researching I found that SQLite does not play well with remote connections. Not only was it causing errors in my application, it was also throwing errors in the parent application.
My alternative was to write an application to query the database that ran locally on the SQLite machine. This fixed all of my issues.
For anyone interested...