IAsyncResult : how to check a message is completed - .NET (Core and Framework) Discussion Boards

I have one problem I don't know how to refresh the panel
(pane.Refresh()-don't work).

I drawing on panel like:

Graphic g = panel2.CreateGraphics();
g.DrawLine(new Pen(Color.Blue), 100,100,200,200);

....

How to Refresh, please help me!

Hi,

Try this instead.

private void panel1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
Refresh();
}

Hope it helps.

Cheers.

Regards,
Chua Wen Ching
Visit us at http://www.necoders.com

Doesn't it seem like this will be the order of events?

* (Your code) Create graphics object
* (Your code) Draw on pane
* (Your code) Refresh pane
* (WinForm code) Clear background (thus removing your previous drawing)
* (WinForm code) redraw pane

It might be that your drawing is getting painted over when you refresh your pane.

You can create a delegate and add it to the pane.Paint event, then draw using the supplied graphics object.

-
Drew

I would like to call methods that are written in visual c++ 6.0 from the .NET environment.
If you know how to do this, please explain in the most simple way.
And if you can also send me a sample I will be glad and thankful!

Poke tongue | ;-P

thanks in advance
sheli

If you have a com or com+ file, you can simply add a reference in VS.NET to that file (VS.NET will automatically create a RCW, a runtime callable wrapper for the file which is like a sort of proxy between the unmanaged code and the managed code) and use it in your .NET code.

Gidon

Can you please send me an example of such com or com+ file?

thanks
sheli

Hi,

You can look into p/invoke! Just assume that you have a C++ dll, and you want to call into your C# application.

[DllImport("yourapp.dll")]
internal static extern int SomeMethod();

Hope it helps.

Cheers.

Regards,
Chua Wen Ching
Visit us at http://www.necoders.com

Hello,
i'm developing a client-server application and now i need to fix my asynchronously receive of messages because sometimes the complete message is not received on a single OnDataReceived call. I've tried for example to send a 18000 bytes long message with a 40000 bytes long receive buffer but there're 2 incoming packets of 13000 and 5000 bytes. My OnDataReceive function is this

<br />
public  void OnDataReceived(IAsyncResult asyn)<br />
{<br />
	try<br />
	{<br />
<br />
		// SocketPacket is a class with the buffer of packet<br />
                SocketPacket socketData = (SocketPacket)asyn.AsyncState ;<br />
<br />
		int iRx  = 0 ;<br />
		// Complete the BeginReceive() asynchronous call by EndReceive() method<br />
		// which will return the number of characters written to the stream <br />
		// by the client<br />
		iRx = socketData.m_currentSocket.EndReceive (asyn);<br />
		if(iRx > 0)<br />
		{<br />
                        // this get client object/class data (nickname, receive buffer for this client, socket)<br />
			ClientSocketType client = GetClientSocket(socketData.m_currentSocket);<br />
<br />
			if(client != null)<br />
			{<br />
                                // create a new receiving buffer for this server/client receive<br />
				if(client.PacketBuffer == null)<br />
					client.PacketBuffer = new MemoryStream();<br />
<br />
                                // append received buffers to that buffer<br />
				BinaryWriter binwrite = new BinaryWriter(client.PacketBuffer);<br />
				binwrite.Write(socketData.dataBuffer, 0, iRx);<br />
<br />
                                // if packets for this message are finished process message<br />
                                // ?!? WORKING ?<br />
				if(asyn.IsCompleted)<br />
				{<br />
                                        // prepare the stream and send to a parsing function<br />
					MemoryStream stream = new MemoryStream(client.PacketBuffer.GetBuffer(), 0, client.PacketBuffer.GetBuffer().Length,true, false);<br />
					ProcessMessage(socketData.m_currentSocket, stream );<br />
<br />
                                        // empty client receive buffer<br />
					client.PacketBuffer = null;<br />
				}<br />
			}<br />
<br />
			// Continue the waiting for data on the Socket<br />
			WaitForData( socketData.m_currentSocket );<br />
		}<br />
		else<br />
		{<br />
			((SocketPacket)asyn.AsyncState).m_currentSocket.Close();<br />
			RemoveSocketFromList(((SocketPacket)asyn.AsyncState).m_currentSocket);<br />
			AddLogMessage("Disconnected user");				<br />
		}<br />
	}<br />
	catch (ArgumentNullException se)<br />
	{<br />
		AddLogMessage(se.Message );				<br />
	}<br />
	catch (ObjectDisposedException )<br />
	{<br />
		System.Diagnostics.Debugger.Log(0,"1","\nOnDataReceived: Socket has been closed\n");<br />
	}<br />
	catch(SocketException se)<br />
	{<br />
		AddLogMessage(se.Message );<br />
		if(se.ErrorCode == 10054)<br />
		{<br />
			((SocketPacket)asyn.AsyncState).m_currentSocket.Close();<br />
			RemoveSocketFromList(((SocketPacket)asyn.AsyncState).m_currentSocket);<br />
			AddLogMessage("User disconnected: no ping received");<br />
		}<br />
	}<br />
}<br />

asyn.IsCompleted gives always True and i'm not able to understand how the message is fully received. What i need to change in this logic?

Thank you

The TCP stack will not necessarily deliver a whole message like this. You have to be prepared to join message fragments together.

You also have to be prepared for multiple messages to be concatenated.

For more information, read the Winsock Programmer's FAQ[^].

Stability. What an interesting concept. -- Chris Maunder

Hi mike,

Thanks for giving me such a valuable information.

Vinu.netguy Big Grin | :-D

hi,

in my system i have .NET 1.1 & .NET 2.0.i hosted a website also.so when i browse the site which version will invoke.

and that application is built on .net 1.1.
what could be the problems updating .net1.1 to .net 2.0.

thanks & regards
naveen.

If you go to your website properties under IIS, you see that with the installation of .NET 2.0 a new tab was added named: "ASP.NET". There you can select your .NET version.

Furthermore .NET 2.0 is fully compatible with 1.1 and 1.0, so .NET 1.1 code can be compiled and run without problems under .NET 2.0

Gidon

hi,

thanQ for reply gnjunge.

its showing as .net 1.1(read only).iam unable to edit the configuration.
And why its taking 1.1 as default instead of 2.0. even i updated to .net 2.0 from .net 1.1.

And one more thing is while browsing iam getting an error as "Server Error '/' in Application".And end of the page its displaying .net version as 1.1.

Thanks & Regards
Naveen.

Hi Naveen,

First of all, if you compile your project in VS 2003, it will use the .NET 1.1 runtime. You can also make it support the 1.0 runtime through your project properties in VS.NET.

"Modifying this property causes the project system to update the web.config file in your project by adding assembly binding (<bindingredirect> and <assemblyidentity>) tags in a <dependentassembly> section. Web pages in Visual Studio-built ASP.NET Web applications are precompiled to a .dll file with a dependency on the runtime associated with the compiler."

I guess setting that option in the ASP.NET tab, will compile the aspx pages on runtime to one supporting the 2.0 runtime (but not the pre compiled files, since that option was set in VS.NET)

So if you would compile your project in VS.NET 2005, it will use the .NET 2.0 runtime.

Gidon

How do I get the key code F5 of the DataGrid?
I use the following code:

FORM:

protected override bool ProcessDialogKey(Keys keyData)
{
switch (keyData)
{
case Keys.Control | Keys.F:
Seek();
break;
case Keys.F5:
break;
case Keys.Escape:
this.Close();
break;
case Keys.F1:
CallHelp();
break;
default:
break;
}
return base.ProcessDialogKey(keyData);
}

DATAGRID:

private void baseDataGrid_KeyPressed(object sender,System.Windows.Forms.KeyEventArgs e)
{
if (e.KeyCode == Keys.F5)
{
this.Cursor = Cursors.WaitCursor;
dsDataSet.Dispose();
dsDataSet = mBaseBuisness.GetAllRows();
m_dvCurrent.RowFilter = "";
baseDataGrid.DataSource = m_dvCurrent;
this.Cursor= Cursors.Arrow;
}
}

I get the key code of all keys, but not from the key F5.

Regards

Uwe

Can anyone tell the diffrence btn. Multithreading and APPDOMAIN, as i know Appdomain is "Application domain is a construct in the CLR that is the unit of isolation for an application." and Mutithreading is " the ability of an operating system to concurrently run programs that have been divided into subcomponents, or threads"

So whats the diff. btn. two and which to be used when?

Vipsi

A thread typically runs a portion of code. If you have more than one thread running (by default they run at the same time) your application is multi-threading. For example, if you were calculating the value for pi to 100,000,000 digits it would take a very long time. You would still want a user to interact with your app while it's calculating, and not "freeze" your app. In this scenario you would use a thread to do the asynchronous work of calculating the value of pi.

An application domain is really just a box to run things in. When you create a new thread it, but default, runs in the application domain of your main program. Now, lets say you have 3 threads running and you haven't created any applicaiton domains. If one thread crashes they will all crash. An application domain gives you the security of keeping everything running inside it from influencing other processes. You can create single or nultiple threads in an application domain. So, if you have 3 threads and each one is in a different application domain, if one thread crashes the other two will continue to run.

That's the basics of it. I'd go to MSDN for the details about how app domains work in terms of security, isolation etc..

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconapplicationdomainsoverview.asp

Thanks. This clears my doubt regarding APPDOMAIN and multithreading.

Hi everybody,

I have a DataGrid in my form that bound to a DataSet, I use background thread to update the data in the dataset, bacause there are a few threads working behind, I don;t want the updated data to be displayed in the Grid until all the threads finish. I try to use SuspendBinding, but it doesn't work.
Does anybody have idea of how to solve it?

Thanks

Alan

Alan Shen

MCAD for .NET Version
^~^~^~^~^~^~^~^~^~^~^
Great idea is the beginging of success!

You could, of course, create two DataSets, and with a simple assignment when your worker thread completes its operation, have the data inserted into the second data set. Then call the Data Binding method, binding to the second data set, and Refresh.
I'll bet you already thought of that, though,...

Hi everybody,

I want to insert thousands of rows into an Access database, I use OleDbCommand to execute the insert sql, but it works pretty slow,
is there any good way to solve the problem?

Thanks for any help in advance!

Alan

Alan Shen

MCAD for .NET Version
^~^~^~^~^~^~^~^~^~^~^
Great idea is the beginging of success!

Actually, in my experience whery big ammount of inserts is allways not too fast, especially if you are executing it in some kind of for() or while() cycle.

Some time ago I created a 2D map in database where insert was wery simple like that: insert (x,y, <somemaptype>) values (1,2,34). In my case I used 2 for() cycles and OdbcConnection with OdbcCommand. insert statement was executed 1`000`000 times and it took 15-20 minutes because someMapType was Random generated number.

I suggest you have to check and try optimize your code, maybe even create transaction sql file and execute it in database side with you oledb. And there is one more thing - Access is the sickest database I ever seen. Maybe you should try some other database.

I used to use classwizard in VC++ 6.0, to add functionality of an event(eg: to override onLButtondown in view class).
I think, The classwizard is not available in VC++ 7.0(.Net version). So how to add this event.
Should I manually add the function signature in c++ and header file?

Thanks
Vinay

Go to the implementation file for the dialog, and then in your Properties window and there should be a toolbar button in it with a green block. Clicking it will list the available MFC overrides.

"Your coding practices might be buggy, but your code is always right."

Internet::WWW::CodeProject::bneacetp
N-Tech Productions
http://www.n-tp.com/

got it. thankyou.