C# Discussion Boards - CodeProject

6-Apr-05 2:37

I am drawing a report using data from database.. I use the GDI+ drawing libraries, system.drawing.dll

The site works on the following computers:
- Microsoft windows 2000 pro Netherlands;
- Microsoft windows 2000 server english;

When i try to use it on a laptop with Windows XP pro SP2 english i get the following error:

"ArgumentExeption:INVALID PARAMETER USED"
I have found out that the error only occurs when the code draws a string. The drawing of rectangles and such work perfectly.

An example of the code on which it crashes is:

<br />
int BlockDateWidth = 2 * 60; <br />
Graphics tmpGraphics = Graphics.FromImage(new Bitmap(1,1)); <br />
.. <br />
.. <br />
objGraphics.DrawString("Startdate", new Font("Arial", 10), Brushes.Black, new PointF( <br />
((BlockDateWidth / 2) - tmpGraphics.MeasureString("Startdate", new Font("Arial", 10), 50).Width) / 2, waMaxHeight - 10)); <br />

i am trying to figure out why it works on 2000 server dutch and english and why it doesn't on that XP and 2003 server machine...

leppie6-Apr-05 2:51

leppie

6-Apr-05 2:51

Hehe, thats the same exception you get when ever GDI+ chokes. Best bet is to just click continue and see what was the last action/method called. In your case, I suspect something with the bitmap size. Why not make it slightly bigger. Or use Graphics.FromHwnd(IntPtr.Zero) (dont dispose!) that will give a 'graphics object to use'.

^{xacc-ide 0.0.15 now with C#, MSIL, C, XML, ASP.NET, Nemerle, MyXaml and HLSL coloring - Screenshots}

Confuzler6-Apr-05 3:12

6-Apr-05 3:12

Invalid parameter used.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentException: Invalid parameter used.

Source Error:

Line 270: objGraphics.DrawLine(new Pen(Brushes.Black, 1), BlockDateWidth, 0, BlockDateWidth, waMaxHeight + 10);
Line 271: //Date labels
Line 272: objGraphics.DrawString("Startdate", new Font("Arial", 10), Brushes.Black, new PointF(((BlockDateWidth / 2) - tmpGraphics.MeasureString("Startdate", new Font("Arial", 10), 50).Width) / 2, waMaxHeight - 10));
Line 273: objGraphics.DrawString("Enddate", new Font("Arial", 10), Brushes.Black, new PointF((BlockDateWidth / 2) + ((BlockDateWidth / 2) - tmpGraphics.MeasureString("Startdate", new Font("Arial", 10), 50).Width) / 2, waMaxHeight - 10));
Line 274: //Workareaname and dividing lines

Source File: c:\data\apmis\src\web\chart\milestoneplan.aspx.cs Line: 272

--------------

Thats the problem i get, i increased the height and width but didnt seem to work...
im trying to work on it..

Confuzler6-Apr-05 3:27

6-Apr-05 3:27

another thing i wonder about is why it does work if i fade out all DrawString commands and it crashes when i dont... the strings that are being drawn lie within the image borders.

Confuzler6-Apr-05 4:57

Add Image icon in textbox

6-Apr-05 4:57

It appears that the following setting prohibits / fails using the DrawString() command of the graphics object.

objGraphics.CompositingMode = SourceCopy;

it looks like the the SourceOver option works i dont know if it is the combination of settings that i have used:

<code>
objGraphics.SmoothingMode = SmoothingMode.Default;
objGraphics.TextRenderingHint = System.Drawing.Text.TextRenderingHint.ClearTypeGridFit;
objGraphics.CompositingMode = CompositingMode.SourceOver;
objGraphics.CompositingQuality = CompositingQuality.GammaCorrected;
objGraphics.InterpolationMode = InterpolationMode.HighQualityBilinear;
</code>

if i had used
<code>SourceCopy</code>
then i get the "INVALID PARAMETER USED" error.

anyway, it works now, if anyone has insight in the real reasons for this to happen, like why <code>Graphics.DrawString</code> can't be used together with
<code>Graphics.CompositingMode.SourceCopy</code>

im glad it works now :->

Adnan Siddiqi6-Apr-05 2:21

Adnan Siddiqi

6-Apr-05 2:21

How could it be done?thers is no default property for it.

Thanks

MyBlogs
http://weblogs.com.pk/kadnan

Re: Add Image icon in textbox

leppie6-Apr-05 2:45

leppie

6-Apr-05 2:45

Why not put it next to it?

^{xacc-ide 0.0.15 now with C#, MSIL, C, XML, ASP.NET, Nemerle, MyXaml and HLSL coloring - Screenshots}

Delegate on a MarshalByRefObject

PEK6-Apr-05 1:17

PEK

6-Apr-05 1:17

I have created an service that communicate with clients via sockets. Now I need some kind of interface to the service so I could close all sockets, get information about the clients and so on.

My idea is to use an singleton object on the server which the (interface-) clients connects to. If a client want to close all sockets it calls a function on the object, and the object then calls a function in the server object which handles all sockets.

But I'm having problem with the communication between the singleton object and the server object. I'm trying to delegate a function on the server object to the client object.

This is the remote object:

public class RemoteObject : MarshalByRefObject 
{
	public delegate bool CloseSocketsDelegate();
	public CloseSocketsDelegate CloseSockets=null;		
}

And this is the server object:

public Server()
{
	ChannelServices.RegisterChannel( new TcpChannel(5050) );
	string url = "tcp://localhost:5050/RemoteObject";
		
	Type serverType = typeof(RemoteObject);
	RemotingConfiguration.RegisterWellKnownServiceType(
		typeof(RemoteObject), "RemoteObject", 
		WellKnownObjectMode.Singleton);

	RemoteObject rem = (RemoteObject)Activator.GetObject(serverType,url);
	
	/* Next line throws an security exception:
	 * 
	 * "System.Security.SecurityException: Type System.DelegateSerializationHolder
	 * and the types derived from it (such as System.DelegateSerializationHolder)  
	 * are not permitted to be deserialized at this security level."
	*/
	rem.CloseSockets = new RemoteObject.CloseSocketsDelegate( this.CloseSockets );
}

How do I solve the security exception? Is there some better way to solve the problem?

S. Senthil Kumar6-Apr-05 1:27

S. Senthil Kumar

6-Apr-05 1:27

Try doing this when registering the channel

IDictionary props = new Hashtable();
int portNumber = 9876;
props["port"] = portNumber;
props["typeFilterLevel"] =
   System.Runtime.Serialization.Formatters.TypeFilterLevel.Full;
try
{
   ChannelServices.RegisterChannel(new TcpChannel(props, clientProvider, serverProvider));
}

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

PEK6-Apr-05 5:03

PEK

6-Apr-05 5:03

Thank, that solved the problem. And it also seems to work as I wanted it too Smile | :)

. I changed the server code to this:

public Server()
{
	BinaryClientFormatterSinkProvider clientProvider = null;
	BinaryServerFormatterSinkProvider serverProvider = new BinaryServerFormatterSinkProvider();
	serverProvider.TypeFilterLevel = System.Runtime.Serialization.Formatters.TypeFilterLevel.Full;
	
	IDictionary props = new Hashtable(); 
	int portNumber = 5050;      
	props["port"] = portNumber;        
	props["typeFilterLevel"] = System.Runtime.Serialization.Formatters.TypeFilterLevel.Full;  
	try      
	{        
		ChannelServices.RegisterChannel
			(
			new TcpChannel(props, clientProvider, serverProvider)
			);         
	}
	finally
	{}

	string url = "tcp://localhost:5050/RemoteObject";
		
	Type serverType = typeof(RemoteObject);
	RemotingConfiguration.RegisterWellKnownServiceType(
		typeof(RemoteObject), "RemoteObject", 
		WellKnownObjectMode.Singleton);

	RemoteObject rem = (RemoteObject)Activator.GetObject(serverType,url);
	rem.CloseSockets = new RemoteObject.CloseSocketsDelegate( this.CloseSockets );
}

Tom Larsen6-Apr-05 4:45

Tom Larsen

6-Apr-05 4:45

I think you are running into a problem using .Net 1.0 remoting in a .Net 1.1 runtime environment. See http://www.thinktecture.com/Resources/RemotingFAQ/changes2003.html[^].

I must warn you right off the bat: delegates don't work well at all across application domains, especially ones that are "remote". There is a good reason why it will now throwing an exception. You can "revert" to old .Net 1.0 behavior but I wouldn't recommend it. Even if you do revert to old behavior it still isn't a good practice to use delegates across applictaion domains especially remoted ones.

Consider if you have three clients where the server triggers

CloseSockets.  The three clients might not even been in a state where they are ready to handle the delgate (ie. delegates are not interupts!).  Also consider that in many networks, the machine requesting/answering is not the machine making the request or answering.  Another machine is doing the NAT/proxy/other network manipulation.  Although it might work for "localhost" you can easily run into problem traversing even intranets.  Again three clients are connected to the server but the server only sees one IP for each of the client.  How does the server know which machine on the "other side" of the NAT/proxy/firewall to contact?<br />
<br />
In general, a client/server network design shouldn't rely on the client telling the server to close socks.  Strong server systems never rely on its client communication protocol for run state instructions.  Clients telling servers "tell me the answer to 3 + 4" is okay.  Clients telling servers to "cut network connections" is bad.  I emplore you to consider another way to do whatever it is you are attempting to do.

PEK6-Apr-05 5:59

PEK

6-Apr-05 5:59

Thank you for your thoughts. I really appreciate opinions about the logic about the program sense I haven’t used remoting before.

I will probably not use delegates but probably interfaces instead. I create an interface with some functions that the server will have, implement the functions on the server and then have an interface-reference on the remote object to server. But when I do this I still get the security exception. Is this is also bad design?

The remote object must in some way communicate with the server object, which I think shouldn’t be a problem sense they a running in the same process. CloseSockets will close all sockets that are running (of course not to the clients that are using remoting). An administrator should only use this if something goes wrong, sockets will normally be closed by the clients.

The remoting object should as I said talk to the server. Mostly of the communications will be about the state of the server (like how many sockets that are currently running, again not the clients that are using remoting), but it will be more complex operations too (like StartCoffeeMachine and TurnOfTheTv).

Tom Larsen11-Apr-05 6:47

Tom Larsen

11-Apr-05 6:47

Using the TV example, the TV remote turns off the TV when you hit "Power". It does not do "a turn off the IR sensor". If it did that your remote is now a brick. Smile | :)

As long as you aren't using .Net Remoting to tell .Net Remoting hosted objects (or a higher abstraction the server/IIS) to close then you are okay. For instance, having a web page in IIS to make IIS to kill itself is a receipe for disaster because of race conditions.

You seem to have a misunderstanding on what .Net Remoting happens to be. The client domain and the server domain certainly are not running in the same process. For instance any reference changed on one domain will not automatically appear in the other domain. The client can simulate synchronization by "blocking" on the response from the server. Things like garbage collection can happen at any moment, independently on either the client or server application domains. You can just as easily do an asynchronous response. The client domain is more than happy to process independent of the server domain and vice versa. Also the assumption that only one client is communicating with the server has to be a strong assumption because .Net Remoting will not enforce that. If your client application exits abnormally will the next client application be able to talk to the server?

One feature of .Net Remoting is that the client domain doesn't have to continually "ping" the server to keep objects alive in the server domain. Once again this is done so the client and server domains can operate independently. The client shouldn't bother finding out what the status of the server domain until it is called upon. There is no need to tell .Net Remoting to clean up itself any more than any other .Net technology (although the facilities are there if you want to twiddle the settings).

I wish you luck on whatever it is you are doing but I would recommend staying away from cross domain delegates and using singleton/single call remoting styles for administration tools.

S. Senthil Kumar6-Apr-05 20:04

S. Senthil Kumar

6-Apr-05 20:04

I don't agree about the intranet thing. If you are concerned about proxies/firewalls, you shouldn't be using TCP, you must be considering using HTTP. Not using delegates means that you won't be able to subscribe to events from the server, do you consider that too to be bad design?

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro