freezing issue with simple client/server - Visual Basic Discussion Boards

Thanks for replying Rage.

This is the code I am using and am getting back an error code (lastDllError code I think) of 998.
I can't seem to find any information on the error codes for SystemParametersInfoA.

Also, as VB.Net doesn't have any "Any" type I have used the VariantType, Object type, and boolean type all to no avail.

'My Code
Private Declare Function SystemParametersInfo _
Lib "user32" _
Alias "SystemParametersInfoA" _
(ByVal uiAction As Long, _
ByVal uiParam As Long, _
ByRef pvParam As VariantType, _
ByVal fWInIni As Long) As Boolean

Private Const SPI_GETSCREENSAVEACTIVE As Long = &H10
Private Const SPI_GETSCREENSAVERRUNNING As Long = &H72

Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick

Dim p_lngRtn As Long
p_lngRtn = SystemParametersInfo(SPI_GETSCREENSAVERRUNNING, 0, bRunning, False)

If bRunning Then
Beep()
End If

If p_lngRtn = 0 Then
Debug.WriteLine(Err.LastDllError)
End If

End Sub

OK. All of your code is good except for one thing. Change all of your 'Long's to Integers. Long's in VB.NET are 64-bit integers and 32-bit in VB6. This is one of your problems. The other is that your VariantType just needs to be an integer. All the pvParam is returning is a boolean value saying True or False. When you call a function that has an ANy type in it, you have to think ahead and replace the Any with the type that you EXPECT to get back. In this case, a 32-bit Integer would work. The corrected code look like this:

Private Declare Function SystemParametersInfo Lib "user32" Alias "SystemParametersInfoA" _
        (ByVal uiAction As Integer, _
        ByVal uiParam As Integer, _
        ByRef pvParam As Integer, _
        ByVal fWInIni As Integer) As Boolean
Private Const SPI_GETSCREENSAVEACTIVE As Integer = &H10
Private Const SPI_GETSCREENSAVERRUNNING As Integer = &H72

Private Sub Timer1_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Timer1.Tick
    Dim p_lngRtn As Integer
    Dim bRunning As Boolean

    p_lngRtn = SystemParametersInfo(SPI_GETSCREENSAVERRUNNING, 0, bRunning, False)
    If p_lngRtn = 0 Then
        Debug.WriteLine(Err.Description)
    End If

    If bRunning Then
        Beep()
    End If
End Sub

Also, when calling into the API, exceptions will not be thrown, and the Err object will not be set at all. You would have to use the return value, 'p_lngRtn' is your code, to determine that an error HAS occured, then you would have to call the API function GetLastError to get the actual error that occured. Your's was probably something like '87 - The parameter is incorrect'.

RageInTheMachine9532

Yup!.. that's solved it alright!
I don't think I woulda ever thought about the difference between vb6 and vb.net integers.. Confused | :confused:

Thanks!

Just one question though, you don't happen to know where the error codes are listed for api errors? I was getting an error code of 998 and couldn't find out what it meant to be able to fix this problem..

Thanks again!

998 wouldn't have told you what the problem was either. It means "Invalid access to memory location." The only thing it would have told you is that your passing an invalid reference to a variable, or memory location.

The complete list of Win32 API errors can be found here[^].

RageInTheMachine9532

Hi

I'm new to VB.Net and when I try to load an existing VB6 project I get a "Security Error"

When I try to start a new project in VB.Net I get a "Required permissions cannot be acquired" error

Can anybody point me in the right direction as to what to do?

Thanks
Confused | :confused:

Stephen

Because .NET can run applications across the net it is concerned that your objects can be hacked by other net users. That's the crude explanation. So there are things called attributes, which you need to read up on, that indicate how certain aspects of your objects are to be controlled, accessed, and things like that. Attributes are a hell of a good idea, as you'll discover, you can do all sorts with them. Anyway, I've digressed. As you are upgrading from 6 to .NET you should take a look at msdn.microsoft.com and read about this process of upgrading, especially to see what's out and what's in if you know what I mean.

There are a lot of issues about upgrading. I learned real quick, its not just plug and play, its plug and pray, pray, pray, then rewrite 8-)

Nursey

So you can't even start a new project? Do you have Administrator rights and are you in the Debugger Users group?

greetz Wink | ;-)

*Niels Penneman*

Software/Dev Site
Personal Site

Hello,
I am just learning the tcp/ip functions etc under vb.net so please look over me if this is obviouse. I have been all over looking into any functions that I didn't totaly understand and can't see that I am doing anything wrong (i obviousely am though)

everything "works", client connects to server and when anything is sent to the server it starts the mp3 and passes all messages the way i ment for it to except that my server is supposed to display the data it recieves in a window (that worked untill i changed some things) and my server will hang after I pass a few strings to it from the client.

The hanging is what I can't figure out. I can debug the other no problem.

Anyway here is the code, please look over how sloppy it has gotten after hours of changeing things arround.

Server :

Imports System.Net
Imports System.Net.Sockets
Imports System.Text

Public Class Form1
Inherits System.Windows.Forms.Form

'Windows Form Designer Generated Code was here "removed for size of post"

Const port As Int32 = 8353
Dim localIp As IPAddress = IPAddress.Parse("127.0.0.1")
Dim server As New TcpListener(localIp, port)
Dim netStream As NetworkStream

Public Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
'start tcplistener on localhost: 8353
server.Start()

Try
'accept connections
Dim client As TcpClient = server.AcceptTcpClient()

'get stream
netStream = client.GetStream

While netStream.CanRead And netStream.CanWrite

'read stream into a byte array
Dim reciveBufferSize(client.ReceiveBufferSize) As Byte
netStream.Read(reciveBufferSize, 0, CInt(client.ReceiveBufferSize))

'convert data from the client into a usable string variable
Dim dataFromClient As String = Encoding.ASCII.GetString(reciveBufferSize)

'do something with the data
TextBox2.Text = dataFromClient

'send a response to the client
Dim serverResponse As String = "Transmision completed"
Dim sendBufferSize As [Byte]() = Encoding.ASCII.GetBytes(serverResponse)
netStream.Write(sendBufferSize, 0, sendBufferSize.Length)

'show what was sent
TextBox1.Text = serverResponse

If dataFromClient.ToString > "" Then
System.Diagnostics.Process.Start("C:\Documents and Settings\devan\My Documents\my music\christian\Did You Feel the Mountains Tremble_ (1).mp3")
End If
End While
Catch exc As Exception
MessageBox.Show(exc.ToString)

End Try
End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
server.Stop()
End Sub
End Class

Client:

Imports System.net
Imports System.Net.Sockets
Imports System.Text

Public Class Form1
Inherits System.Windows.Forms.Form

'Windows Form Designer Generated Code was here "removed for size of post"

Dim client As New TcpClient
Dim netStream As NetworkStream

'If theres a problem check if this should be public for both client and server
Public Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
'establish connection

client.Connect("127.0.0.1", 8353)

netStream = client.GetStream

'show connection status
If netStream.CanRead And netStream.CanWrite Then
StatusBar1.Text = "connected"

''do simple write
'Dim clientCommand As String
'clientCommand = TextBox1.Text.ToString
'Dim sendBytes As [Byte]() = Encoding.ASCII.GetBytes(clientCommand)
'netStream.Write(sendBytes, 0, sendBytes.Length)

'' Read the NetworkStream into a byte buffer.
'Dim bytes(client.ReceiveBufferSize) As Byte
'netStream.Read(bytes, 0, CInt(client.ReceiveBufferSize))

''Do something with data from server
'Dim dataFromServer As String = Encoding.ASCII.GetString(bytes)
'Label2.Text = dataFromServer.ToString

Else
If netStream.CanRead = False Then
StatusBar1.Text = "cannot write to stream"
Else
If netStream.CanWrite = False Then
StatusBar1.Text = "cannot read stream"
End If
End If

End If
End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

'do simple write
Dim clientCommand As String
clientCommand = TextBox1.Text.ToString
Dim sendBytes As [Byte]() = Encoding.ASCII.GetBytes(clientCommand)
netStream.Write(sendBytes, 0, sendBytes.Length)

' Read the NetworkStream into a byte buffer.
Dim bytes(client.ReceiveBufferSize) As Byte
netStream.Read(bytes, 0, CInt(client.ReceiveBufferSize))

'Do something with data from server
Dim dataFromServer As String = Encoding.ASCII.GetString(bytes)
Label2.Text = dataFromServer.ToString
End Sub
End Class

Thanks in advance if anyone can help me figure this out.

I'm not an expert on the sockets stuff, but my gut feeling makes me wonder if the loops you are in need a DoEvents to keep the events running through the rest of your application.

You could also use the system.diagnostics namespace to get access to the Debug object and start writing some assert and trace statements, that will show where your code is stopping. It really might just be that it looks like its hung when in fact its in such a tight loop it can't do any of the event stuff it needs to do. So the doevents will yield for a time and let the system do its thing.

Nursey

Thanks,
I haven't gottin real deap into the diagnostics namespaces but the whole purpose is to learn so I'll look into it. Defenetly sounds like a good thing to learn to use for debugging.
Thanks again.

2 U.S. coins equal 30 cents and one is NOT a nickle. Hmm..

How to get all the controls in the form, like in VB we used to do

for each ctrl in me

if typeof ctrl is Textbox then
ctrl.text = ""
end if

next

How we do this in VB.Net.???

Thanks

Smile | :)

Be Humble in Victory and Strong in Defeat. Smile | :)

-Het

You need to use the Controls property, which all forms have, and it seems all controls have. So your panels can have a collection of controls. You can do this

dim lControl as Control

for each lControl in Me.Controls
...
Next

Me is a form or Panel or any control.

The typeof works the same.

Hope this helps.

Nursey

may i know if there is any sample codes on how to link vb.net GUI with c++ DLL functions? thanks

That is hellishly difficult. C++ compilers mangle the names of classes and functions so that they can be uniquely identified. The names exposed by the DLL will be the mangled versions such as "@MyClass@#SomeFunction@$%$@%@@". The mangled format is different for most compilers, and sometimes different between different versions of the same compiler.

--Colin Mackay--

Like Colin said, LINKing is hellishly difficult. Or are you trying to CALL functions in a C++ .DLL. If so, you can start reading up on it here[^]. This is an article showing how to call DLL functions using P/Invoke in VB.NET. VB6 is very similar to this.

RageInTheMachine9532

Hello All..
I guess you have see attachments embedded in Word Document like email having attachments.

I use MSWord automation with VB to get those attachments. I can only get the name of the attachments but can't find the way to save them.

If you have the word document which contains attachments like .jpg, .pdf, .xls, .ppt files, select one of the attachment files and either right click or go to Edit menu of Word application and you will see
File Object-> save as, open, print, convert.. etc.

I think there should be the function that allow me to save those attachments programmatically since you can save them mannually in MS Word.
I want to save as the attachment.. and cannot find the way to do it in Word reference.
does anybody know how??

I Don't wanna go to Add/Remove Program to Uninstall my application. How I create a shortcut to do that?

Johnny Lizardo

This information is stored in the registry, where you will find the display string and path to the uninstaller.
Check this site out: http://windows.about.com/library/tips/bltip619.htm Wink | ;-)

and... is this VB/VB.NET?

greetz Wink | ;-)

*Niels Penneman*

Software/Dev Site
Personal Site

IS VB.NET..

Johnny Lizardo

It's works. Thank You men..

Johnny Lizardo

Anyone know's about bootstrapper plug-in.?

I have a problem with that. I already installed from "http://www.gotdotnet.com/Community/Workspaces/workspace.aspx?id=2f8f0a23-f529-4158-8e0a-d187d16f41f1"

but don't change anything about automatic install the dotnetfx.exe and MDAC.

Anyone help...

Johnny Lizardo

Maybe use the documentation link on the site ... you need .net passport but i guess almost everybody has one now ... Poke tongue | ;-P

greetz

*Niels Penneman*

Software/Dev Site
Personal Site

hi
happy new year to all

i am from india, i want to programm an application in VB 6.0 to implement a regional font. is this possible , if so how can i do it ? i mean if i set the font for a text box to that font will it take the same letters as expected ? and i want to generate the reports in the same font also...

pls. any one help me

Mohan G

This doesn't make any sense to me. Do you want to create a new font? Or do you want to use fonts that have the same character sets? Or are you talking about typing chracters in a text box in the local language?

In any case - I think what your getting at is "localization". For more information on localization and VB6, you might want to start here[^].

RageInTheMachine9532

hi rage
thanx for your reply. yes i am "talking about typing chracters in a text box (or in any editable intrinsic control) in the local language?. is this possible ? can you show me a way out here please ?

Mohan G