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Hello everyone, I have a problem that I have been banging my head against the wall for the past few days trying to figure out...I am writing a remote assistance service and I want to send a file(a .jpg) using tcp/ip blocking sockets. I have used MANY other peoples source code, but still the file never arrives or I get ugly unhandled exceptions...I finally found one that sort of works...It sends a snapshot of the users screen ONE time, after that the client gives me a "connection reset by software on your remote host", I have included the client and server methods that are running in a seperate continuous thread...your help is MUCH appreciated.
P.S. sorry for the bad formatting.
<---Client source snippet--->
public static void BeginSnapShotSend()
{
ScreenCapture SC = new ScreenCapture();
try
{
// get the remote IP address...
IPHostEntry IPHost = Dns.Resolve("localhost");
IPAddress[] ip = IPHost.AddressList;
int iPortNo = System.Convert.ToInt32(443);
//create the end point
IPEndPoint ipEnd = new IPEndPoint (ip[0],iPortNo);
//connect to the remote host...
PicConnect.Connect ( ipEnd );
nfs = new NetworkStream(PicConnect) ;
}
catch (SocketException SE)
{
System.Windows.Forms.MessageBox.Show(SE.ToString());
return;
}
while (true)
{
SC.CaptureScreenToFile("sc.jpg", ImageFormat.Jpeg);
Thread.Sleep(1000);
try
{
FileStream fin = new FileStream("sc.jpg",FileMode.Open , FileAccess.Read) ;
//Get the Length of the file requested
//and set various variables
long total=fin.Length;
long rdby=0;
int len=0;
byte[] buffed = new byte[4096];
//Open the file requested for download
//One way of transfer over sockets is Using a NetworkStream
//It provides some useful ways to transfer data
byte[] m_sbuf = System.Text.Encoding.UTF8.GetBytes("fsize"+" "+total.ToString());
PicConnect.Send(m_sbuf);
Thread.Sleep(1000);
//lock the Thread here
while(rdby<total&&nfs.canwrite)
{
="" read="" from="" the="" file="" (len="" contains="" number="" of="" bytes="" read)
="" len="fin.Read(buffed,0,buffed.Length)" ;
="" write="" on="" socket
="" nfs.write(buffed,="" 0,="" len);
="" increase="" counter
="" rdby="rdby+len" ;=""
="" }="" display="" a="" message="" showing="" sucessful="" transfer
="" fin.close()="" }
="" catch(exception="" ed)
="" {="" system.windows.forms.messagebox.show("a="" exception="" occured="" in="" transfer"+ed.tostring())="" ;
="" return;
="" }
<---server="" snippet---="">
public void raptwm()
{
IPAddress ipAdress = IPAddress.Any;
IPEndPoint Enp = new IPEndPoint(ipAdress, 443);
Socket ListenTehCliPic = new Socket(AddressFamily.InterNetwork,SocketType.Stream, ProtocolType.Tcp);
ListenTehCliPic.Bind(Enp);
ListenTehCliPic.Listen(0);
Socket WorkWitTehCli = ListenTehCliPic.Accept();
NetworkStream nfs = new NetworkStream(WorkWitTehCli);
ListenTehCliPic.Close();
while (true)
{
bool done =false ;
bool check= false ;
long size=0 ;
long rby=0 ;
while(!done)
{
//declare a buffer
byte[] rce = new byte[2048];
//Recive a Sever Message
waitagain:
int i = WorkWitTehCli.Receive(rce,rce.Length,0) ;
//Convert it to string
string sm = System.Text.Encoding.ASCII.GetString(rce);
if(sm.StartsWith("fsize"))
{
string sizeoffile = sm.Remove(0,6);
//store the File Size
size=Int64.Parse(sizeoffile);
done=true ;
check=true ;
}
else
{
goto waitagain;
}
}
//The File Size has been received the continue
done=false;
//Make a File with the same name as the File that is being downloaded
//Also open a Network Stream to the Server
FileStream fout = new FileStream("sc.jpg", FileMode.OpenOrCreate , FileAccess.Write);
byte[] buffer = new byte[4096] ;
while(!done&&check)
{
try
{
long v=0 ;
//loop till the Full bytes have been read
while(rby<size)
{
="" read="" from="" the="" network="" stream
="" int="" i="nfs.Read(buffer,0,buffer.Length)" ;
="" if(i="">0)
{
//Some checking done to detremine the number of Bytes to be written
if(i>=4096&&(size-rby)>=4096)
{
v=4096 ;
}
else if(i<4096 &&(size-rby)>=4096)
{
v= i;
}
else
{
v=(size-rby) ;
}
//Write the Bytes received to the File
fout.Write(buffer,0,(int)v) ;
rby=rby+v ;
}
}
fout.Close() ;
done=true;
Thread.Sleep(100);
pictureBox1.Image = Image.FromFile("sc.jpg");
}
catch(Exception ed)
{
MessageBox.Show(MW,"A Exception occured in file transfer"+ed.ToString());
}
}
}
}
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I have yet to figure out what everyone's infatuation with writing a VNC-like application in C# is. This is really not a good idea, mind you.
Not only are there already clients that do this installed in Windows (NetMeeting is standard in Win98 and Win2K and newer, or some form of it; Windows XP already has remote assistance that's very flexible) but you can even use some of the APIs like NetMeeting to integrate into your own application.
The true remote desktops don't use an entire screenshot, but a virtual frame buffer. Consider this: when a region is invalidated in Windows, it sends the WM_PAINT message with an HRGN that specifies what needs to be repainted (in .NET, this corresponds to the Paint event and the PaintEventArgs.ClipRectangle property). This may be an entire window or just a portion of it. But the entire screen is not drawn each time. By using a virtual frame buffer you take advantage of this (requiring much less bandwidth). Only the bits for the newly drawn portion are transferred across the wire.
It's this approach - if you're intent on reinventing the wheel (there's lots of "wheels" already, many very heavily tested) - you should look into. Unfortunately, .NET is too high level for such a task. Even if you do manage to P/Invoke all the native APIs you'll need an declare all the structs and consts, you'll incur performance penalties because of marshaling. You could, of course, write a Managed C++ assembly that alliviate most of these problems (mixing unmanaged and managed code to make such functionality accessible to other .NET assemblies written in any language).
What you're currently doing will have problems like you're seeing. Far too much bandwidth is required and will most likely require more time to transfer than your current refresh time, creating a large bottleneck that won't go away and will eventually cause timeouts (pretty quickly). The more lag on the wire, the faster timeouts will start occuring.
Microsoft MVP, Visual C#
My Articles
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wow, ok thanks for your help. I totally forgot about using netmeeting, and I didn't truly realize how difficult such a thing could be.
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I want to write a C# Serial communication program,but I am poor in C#,I usually did these in vc++6.0 before.
What should I do if I want to use C#?
Is there any example about these??
Thanks!!
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I typed "RS232 C#" into google and found many results[^]. If you're looking for something specific, it's usually a good idea (and most often the fastest) to search first (whether it's this side, this forum, or on the entire indexed web).
Microsoft MVP, Visual C#
My Articles
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Thanks!!
The google is very uesful,I have got what I want.
someone has wrote a class for .NET serial communciation,the class name is JH.CommBase.
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Here is an issue I've run into from time to time while creating C# applications. Let's say I have a model which represents the business domain of my application. To present this model to my users, I have a GUI layer.
Let's say that there is a combo box that is a part of the GUI. The user clicks on the combo box and makes a selection. This triggers an event. In response to this event, the model is updated.
Very, very simple. But...
When updating the model from an outside source, say a file or whatever, the GUI will need to be updated to represent the model accurately. Continuing with the combo box example, if you set the SelectedIndex property to a value programmically, an event will be raised to indicate that the property has changed. So when updating the GUI, events are raised in response. And using the logic set up to respond to those events, the model will be updated unnecessarily.
In the case of the ComboBox and its SelectedIndex property, there is no distinction made between the property being modified as a result of user interaction and being modified programmically.
One obvious approach would be to disconnect from the events when you don't want to respond to them and reconnect afterwards. But with a lot of controls, that could lead to a lot of code. What this has led me to do is to use a boolean variable to indicate whether or not the model should be updated when an event is raised by the GUI controls. But this solution feels kludgish.
I was wondering if other C# programmers have run into this problem and how you dealt with it.
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There's nothing wrong with using state variables. State variables are used throughout the entire .NET BCL (base class library) and many, many other applications. It's practically impossible to write a decently sized application without state variables.
And they result in far less instructions that attaching and detaching event handlers like you mention. To assign a state variable is (assuming an instance field) 2 IL instructions. To check that variable and branch accordingly is another 2-3 instructions (depending on if else is used immediately after the if with no else if in between). Hooking up an event handler - even in your code - takes many more instructions, and many more instructions are required by the delegate to combine the list (even if previously empty) of handlers.
Microsoft MVP, Visual C#
My Articles
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Is is possible to pass a form control to a class?
ex. passing a listView control to a class so I can access the contents of the listView.
Thanks
Budha_man_99
Bas spellers of the world Untie!!
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budha_man_99 wrote:
Is is possible to pass a form control to a class?
By class I am assuming you really mean an instance of a class (an object). Yes, it is possible. You can pass any object to another object and a form control is just an object.
The real question is how do you want to pass the form control to your object. Via the constructor? Through a property's setter? In a method call?
"If a man empties his purse into his head, no man can take it away from him, for an investment in knowledge pays the best interest." -- Joseph E. O'Donnell
The Second EuroCPian Event will be in Brussels on the 4th of September
Can't manage to P/Invoke that Win32 API in .NET? Why not do interop the wiki way!
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Colin,
I am attempting to use a method call.
Thank you
budha_man_99
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Your class can contain something like this...
public class MyClass
{
public void MyMethod(System.Windows.Forms.Control theControl)
{
}
}
From the Form (I'm assuming this is where you are coming from, you've not been very explicit about this) something like this....
public void SomeMethodInTheForm()
{
MyClass theClass = new MyClass();
theClass.MyMethod(this.theTextBox);
}
Voilá.
Does this help?
"If a man empties his purse into his head, no man can take it away from him, for an investment in knowledge pays the best interest." -- Joseph E. O'Donnell
The Second EuroCPian Event will be in Brussels on the 4th of September
Can't manage to P/Invoke that Win32 API in .NET? Why not do interop the wiki way!
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This is exactly what I'm looking for. Thank you very much.
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I have a tab control on my form which can resize. The tab control itself is ancored and resizes ok. Each tabPage has a few buttons whcih get resized ok to a point. The active tabPage control's buttons reisze ok, but then switching to another tabPage I find that the buttons raen't in the correct horizontal positions. If I resize the form again the 2nd tabPage which had the buttons repositioned incorrectly will position the buttons ok, but switch back to the 1st tabPage and it's buttons are now in the wrong place!!!
I have tried embedding each button in its own panel control and ancoring the button left & right to its parent panel and the panel itself being anchored bottom & left and the other panel with embedded button bottom & right. This doesn't work either and it seems that the anchoring only works for the active tabPage.
I have also tried postioning the buttons in the resize event which only works fine for the active tabPage.
Has anyone else come accross the problem of correctly resizing buttons which need to grow their width property in proportion to the tabPage width? I am leaving the height unchanged. Anyone know of a way to correctly adjust the width and left properties correctly for non active tabPage's?
For the record I have about 6 tabPages, some have only two buttons adjacent to one another, other tabPages have five buttons adjacent to each other. In each tabPage the buttons need to increase/decrease their width property and adjust their left property also.
I have run out of ideas. And no I can't leave the width properties as static.
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Hi,
Late last night I found a great C# example on thecodeproject.com and downloaded the demo (not the source). It was a c# custom control that drew colored buttons (and switched the images when clicked). They were roundish -- oblong, not circular. Now, in the light of day I can't find the project and I'd really like to see the source code. The file I downloaded was ColorButtonExample.zip, but I've searched for those words and can't find that example again.
If any of you know what I'm talking about and could send me the link I'd really appreciate it.
thanks,
Deanna
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Hi,
do you mean this:
Custom Button with Color and Shape[^]
Gary
"A fellow with the inventiveness of Albert Einstein but with the attention span of Daffy Duck."
Tom Shales talking about Robin Williams
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THAT's IT!! Thanks, Gary. I'm living proof that too much Aspartame (Diet DP) can rot your brain!
thanks so much,
Deanna
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Anonymous wrote:
THAT's IT!! Thanks, Gary. I'm living proof that too much Aspartame (Diet DP) can rot your brain!
thanks so much,
Deanna
Your brain can't be too bad if you can remember the name "Asparame", sound like a Disney character 
Gary
"2400 Baud makes you want to get out and push !"
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I want to have a edit menu with the usual cut copy paste functions but I am not sure how to write the generic code for doing this. I want it to operate the same as when you right click on a text box. Can anyone point me in the right direction?
Thanks so much!
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There lots of articles here on CodeProject that discuss undo/redo functionality using a variety of methods from structured commands to handled page faults. I suggest you try a search.
Microsoft MVP, Visual C#
My Articles
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Also if you use a RichTextBox, they support Undo / Redo operations.
Gary
"A fellow with the inventiveness of Albert Einstein but with the attention span of Daffy Duck."
Tom Shales talking about Robin Williams
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Undo feature of RichTextBox has bug. Undo information is lost once you get the text using Text property i.e. richTextBox.Text.
Please refer the following article for detail.
Microsoft Knowledge Base Article-812943
Regards,
Jay.
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Hi,
A while back I was reading about passing parameters to C# properties and loving it. But I must have been dreaming because now (that I'm ready to use them) I can't find any mention of them. Was it only a dream?
Thx,
MAtt
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No, you can pass parameters like this (excuse the pun)
public MyObject this[int index]
{
get
{
return (MyObject) InnerList[index];
}
}
as you can see I've ripped this code from a CollectionBase derived class.
You can pass more than one param within the [] brackets
Gary
"A fellow with the inventiveness of Albert Einstein but with the attention span of Daffy Duck."
Tom Shales talking about Robin Williams
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hello forum,
i have defined a web service. If the remote operation is successful the method must return a type of datum (for example, struct Okstr) but if the remote operation is not successful the method must return another different type of datum (for example, ERRORstr).
How Can i do this with Web Services??
Is possible to throw exceptions via Web Services (like JAVA RMI or CORBA)?
A lot of thanks!!
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