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AFAIK, ping[^] is the efficient way for this. Just ping the device and if you are getting acknowledgement, consider it as active.
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i know but ping will only tell if the device is connected to the network..it will not tell me if there is an active connection(ie that there is some data flow between the device & pc).
For instance the device is connected to my application(i can ping it as well)...however if i pull out the cable and plug it in back again..i can still ping it...but it isn't connected to my application anymore...so the ping check is not enough for this..it wont tell me if it is connected or not..is there some way to do this with sockets and ports?
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Hello again,
for those who saw it: I asked the question already some time ago, but I just got answers that couldn't help me solve the problem. Maybe there's someone around who's willing to guide me a bit more detailed? ![Rose | [Rose]](https://www.codeproject.com/script/Forums/Images/rose.gif)
All I wanna do is show a picture (DPX-File) in a picture box on a form. Unfortunately DPX is not supported from GDI+, so I have to find an uncommon way in VB2008. What I found: The image information in a dpx-file starts after a header of specified length at Address &h2000. Each pixel is represented by a 32-bit-word (4 Bytes) which I would be able to read e.g. using a binary reader.
With which code could I get the information read by a binary reader into my picture box? I read about memorystreams, blobs etc but I can't figure out  which way would work and how...
Any advice is very appreciated!
Thank you for you time,
Michael
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Hi,
this is a two-step job:
1. convert your image file to a Bitmap object
2. display the Bitmap
1. may or may not be simple, depending on the image format.
If you're lucky the Bitmap(Int32, Int32, Int32, PixelFormat, IntPtr) constructor is appropriate. If not, you have to:
a. get the dimensions
b. create a Bitmap of that size
c. get each pixel from the file and call bitmap.SetPixel
Luc Pattyn [Forum Guidelines] [My Articles]
The quality and detail of your question reflects on the effectiveness of the help you are likely to get.
Show formatted code inside PRE tags, and give clear symptoms when describing a problem.
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Thank you, Luc.
I'm about digging into information about the Bitmap-Constructor as you recommend... to find out if I'm lucky  I'd be glad if you'd help me along with a code example regarding the 'scan0' Parameter.
Public Sub DisplayImage(ByVal PicFile As FileInfo)
Dim width As Integer = (2048 / 10)
Dim height As Integer = (1536 / 10)
Dim stride As Integer = (4 * 2048)
Dim format As PixelFormat = PixelFormat.Canonical
Dim scan0 As IntPtr
Dim DPXBitmap As New Bitmap(width, height, stride, format, scan0)
PictureBox1.Image = DPXBitmap
End Sub
Or would it be possible using a filestream to create the bitmap? Something like
Dim ft As FileStream
ft = New FileStream(PicFile.FullName, FileMode.Open)
ft.Position = 8192
Dim DPXBitmap As New Bitmap(ft)
PictureBox1.Image = DPXBitmap
ft.Close()
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I don't think a stream will work, IIRC new Bitmap(stream) tends to rewind the stream before processing it. What you should consider is this:
declare an array of bytes, fill it with pixel data from the stream; then use the GCHandle class to pin it and get the IntPtr, then use the Bitmap constructor. All this assuming the data is layed out in a way that matches one of the supported pixelformats.
if not, you have to:
- either fill the byte array yourself in an acceptable pixelformat;
- or use SetPixel (which is bound to be slower).
BTW: I'm not sure what the division by 10 is doing in Dim width As Integer = (2048 / 10); if you hope to resample the image while loading, that has zero success probability. Load it as is, then do whatever you have to to it.
Luc Pattyn [Forum Guidelines] [My Articles]
The quality and detail of your question reflects on the effectiveness of the help you are likely to get.
Show formatted code inside PRE tags, and give clear symptoms when describing a problem.
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Wow... even reading your advice is a challenge for me novice 
I'll try my best to understand what 'use the GCHandle class to pin it' might mean and how I could then get the IntPtr... ? Or would you please be so kind as to show with a few lines of code what you mean?
Thanx again
btw: you were right that I tried to resize the picture for display by dividing the originals width and height by 10. Your advice helps avoiding that additional trap 
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So as a novice the first thing you want to do is read some strange image format? Good for you! I won't embarras you with any code samples, I'd rather suggest:
1) you read up on the GCHandle class, it is a little class and you will need it (unless you use the slower way with Bitmap.SetPixel);
2) you read a good tutorial on VB.NET (Here[^] is why).
Luc Pattyn [Forum Guidelines] [My Articles]
The quality and detail of your question reflects on the effectiveness of the help you are likely to get.
Show formatted code inside PRE tags, and give clear symptoms when describing a problem.
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Hey Luc...
too sad you're in a bad mood obviously - your 'read a tutorial' standard answer is not very helpful  . Or did you invest in bookshop shares recently?
The task to handle a 'strange' or let's say unsupported (btw the standard for movie interchange!) picture format might be challenging, but that's why I ask in a programming forum even after buying some books, right? Even a good Cessna pilot has to consider himself as a novice when it comes to the F-16, so why do you have to embarras me with such a silly statement instead of guiding me to an advanced technique that you probably know?
Nevertheless, I wish you a nice evening and a good glass of wine... and I'll go read about the GCHandle class, anyway.
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Have a look at this[^]. The source code is available for download, so you should be able to read it and see how they have handled DPX files.
Steve Jowett
-------------------------
Real programmers don't comment their code. If it was hard to write, it should be hard to read.
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Thank you, Steve.
Unfortunately it's all in C++ which I have absolutely no idea of. It's the same with GraphicsMagick / ImageMagick, which I had considered to examine before. So for the moment I'm trying to find a way out with the Bitmap-Constructor how Luc recommended.
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hi all,
I am into a new project to read new mails from a mail server and put into database. i tried pop3 .But in that all mails from sent items and inbox at time . So i decided to use IMAP
I modified the POP3 code which i was using an tried like this
created a TCP object
Dim objTCP As New TcpClient
Dim sslstream As Net.Security.SslStream
Dim reader As StreamReader = Nothing
objTCP.Connect("imap.gmail.com", 143)
sslstream = New Net.Security.SslStream(objTCP.GetStream())
sslstream.AuthenticateAsClient("imap.gmail.com") ' authenticate as client GMAIL
reader = New IO.StreamReader(sslstream) ' Assigned reader to stream
it caught an error on the authentication part "sslstream.AuthenticateAsClient("imap.gmail.com")"
I am pasting the error below
System.IO.IOException = {"Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host."}
InnerException = {"An existing connection was forcibly closed by the remote host"}
Can you point out the error in my code.
If i am wrong Can you help me to get the basic commands running .
I am new to this network level programming
thanks & regards
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What is the best practice for placing general-purpose routines which will be widely used? To date, I've tended to simply have a ModGlue.vb file in each project, where I throw any that I need, but moving classes between projects requires locating and copying in the appropriate stuff from ModGlue, which is somewhat tedious and will become moreso the longer I go without a better strategy.
Some of the general-purpose routines are things like:
Function Byt(ByVal v as Integer) As Byte
Return CByte(v and 255)
End Function
Function HexArr(ByVal dat() as Byte) As String ' Returns hex representation of array
Function ByteString(ByVal dat() as Byte, ByVal Length As Integer) As String ' Converts bytes to string (by character code)
Sub Zap(ByRef it as iDisposable)
Dim oldIt as iDisposable
oldIt = it
If oldIt IsNot Nothing then
oldIt.Dispose
Threading.Interlocked.CompareExchange(it, Nothing, oldIt)
EndIf
End Sub
In many cases, things that sorta should have been part of the .Net framework, but aren't. What's the best way to make sure that the necessary functions get brought in when copying a class from one project to another, without ending up with extraneous or duplicated methods?
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Build a dll you import into all your projects.
Christian Graus
Driven to the arms of OSX by Vista.
Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
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As CG said, create a class project, put all your utility snippets in there and reference it from every project.
The only problem with this is my util never stays the same for long enough to create a DLL. Housekeeping this DLL can be a major job, otherwise it just continues to grow. I moved from VB to C# last year and had to rewrite all my utilities and DAL, one of the best excercises I have ever done, shrank by 40%.
Never underestimate the power of human stupidity
RAH
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I've never managed to create a DLL that I could "references". I have managed to create DLL's which I could use by explicitly importing them at run-time (hardcoding the path to the DLL) but that seemed really incredibly icky. I'm using a mix of VS2005 and VBex2005; I'd probably just use VS except that I have VS set to one color scheme and VBex to another; if I could set different projects to different color schemes, I'd probably just standardize on VS, but I've asked repeatedly how to do such a thing and never gotten any response.
To be sure, the DLL's I've created have been in straight C rather than C# or VB, but I'm still wondering what step I'm missing.
Otherwise, I wonder if there are any good utilities which can take some source files and aggregate all the stuff that matches, flagging anything that doesn't. Merge all identifiers within a module or namespace that have identical definitions; for classes without control definitions, merge everything but fields. For control definitions, prompt the user for what to do about mismatches. Do any such handy tools exist?
Also, you say you go in and clean up your multi-purpose project periodically. How do you ensure that nothing breaks when you do that?
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i am wondering if you are over thinking it. Grab everything that you think other apps would benefit and just move them into a class-library project (dll). All the name spaces that you have created (if any) still exist. You might need to add references to system libraries that natually come with a windows application (drawing/window.forms/etc). In your windows app, reference the new dll and import the new dll in your form or whereever else you need it. Same code that worked in one project now works spanning another project with the benefits of intellisense, etc(lose that at run-time load assembly).
Nothing breaks --> to verify all projects are compatiable with the changes made in your new shared dll, just create a "master" solution and add all projects in there. make your changes and then compile the master solution and if successful...you know at least syntax wise all is compatible...
'Never argue with an idiot; they'll drag you down to their level and beat you with experience.' ~ anonymous
'Life's real failure is when you do not realize how close you were to success when you gave up.' ~ anonymous
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Yup - do what Larson said, this really is a simple excercise.
I have no idea what VBex is so I can't comment on it but VS C#/VB allows you to simple make a class library project, compile it and reference it in other projects.
Never underestimate the power of human stupidity
RAH
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I am using following code to populate dataTable and then updating Access Table. I am getting error "OleDbException was unhandled" "Syntax error in INSERT INTO statement.
Any help would be appreciated.
Thanks,
Aman
<br />
Private Sub dataGridAccess()<br />
<br />
Dim connString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & AccessFile<br />
Dim myConnection As OleDbConnection = New OleDbConnection<br />
myConnection.ConnectionString = connString<br />
myConnection.Open()<br />
<br />
<br />
Dim myTable As String = "RealTimeWQActual"<br />
Dim myCmd As String = "Select * from " & myTable & " ORDER BY sdate"<br />
' create a data adapter <br />
Dim da As OleDbDataAdapter<br />
Try<br />
da = New OleDbDataAdapter(myCmd, myConnection)<br />
Catch ex As Exception ' Catch the error.<br />
MsgBox(ex.ToString) ' Show friendly error message.<br />
End Try<br />
<br />
MsgBox(myTable & " " & myCmd)<br />
''Dim dr As New OleDbDataReader<br />
' Create command builder<br />
Dim CB As OleDbCommandBuilder = New OleDbCommandBuilder(da)<br />
' create a new dataset <br />
Dim ds As DataSet = New DataSet<br />
' fill dataset <br />
da.Fill(ds, myTable)<br />
' Insert code to populate the DataTable with rows.<br />
' Set the DataSource and DataMember of the DataGrid control.<br />
DataGrid1.SetDataBinding(ds, myTable)<br />
<br />
Dim dt As DataTable = ds.Tables(myTable)<br />
Dim rrows = dt.Rows.Count<br />
MsgBox("rrows= " & rrows)<br />
<br />
' NewRow to create a DataRow.<br />
Dim row As DataRow<br />
row = dt.NewRow()<br />
<br />
' Then add the new row to the collection.<br />
row("SDATE") = "1"<br />
row("STIME") = "1"<br />
row("Parameter") = "1"<br />
row("Value") = "1"<br />
row("d1") = "1"<br />
row("d2") = "1"<br />
<br />
dt.Rows.Add(row)<br />
'**** error comes at the next step ***<br />
da.Update(ds, myTable)<br />
'**** Program runs without the previous step and dataTable shows the added row<br />
myConnection.Close()<br />
<br />
<br />
End Sub<br />
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I am guessing you need to provide the adapter with an insert statement ?
Christian Graus
Driven to the arms of OSX by Vista.
Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
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Here I used ACE.OLEDB.12.0. for office 2007-Access [accdb] But I want you to use Jet.Oledb for office 2003-Access [mdb]
Dim Ithuva As String = "Samples To Aman"
con = New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Temp\sample1.accdb;Persist Security Info=False")
con.Open()
Dim CmdTxt As String = "Insert into address (city) values ('" & Ithuva & "')"
Dim cmd As OleDbCommand = New OleDbCommand(CmdTxt, con)
cmd.ExecuteNonQuery()
con.Close()
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Do you have any primary keys defined for the underlying table?
If you don't OleDbCommandBuilder will not work.
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I am trying to find a program in Visual Basic that will list all open windows on a computer. I am trying to activate a window based on it's title bar. I've looked up EnumWindows and GetWindow for examples but I am running into problems with the code I find (it doesn't work). I'd like to find some code that does. I have a intranet website that shows customer info and i'd like to activate a window based on the number they called. I want to call this program with a variable that will bring a window to the forefront based on that variable. Any help you provide would be most appreciated.
Thanks for all the help
NewbieDave
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I don't know that you can enumerate windows on a client, from the server.
Christian Graus
Driven to the arms of OSX by Vista.
Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
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