Re: Error?!! - C# Discussion Boards

19-Dec-06 22:10

i encrypt my database(access) and when my project is running , the database is decrypt and copy on system32 , and after that when the project is closing i delete the database on system32 folder .

it is ok on my computer , but when i run it on another computer , the db decrypt successfully , but in one of my function which i use connection.open , show following error :

could not use ;file already in use

how could i solve this error?!!!

Guffa19-Dec-06 22:26

Guffa

19-Dec-06 22:26

Make sure that the method that creates the file closes it properly.

---
It's amazing to see how much work some people will go through just to avoid a little bit of work.

Nafiseh Salmani19-Dec-06 23:37

19-Dec-06 23:37

if that method dosn't close it, why there is not any problem on my computer?

Guffa20-Dec-06 1:47

Guffa

20-Dec-06 1:47

There can be many different reasons why code that is not completely correct may work in one place but not another.

Among possible reason can be different file systems, different memory load, different cpu load, different operating systems.

---
It's amazing to see how much work some people will go through just to avoid a little bit of work.

Dave Kreskowiak20-Dec-06 6:02

Dave Kreskowiak

20-Dec-06 6:02

You said you're putting this database in the \Windows\System32 folder? Did it occur to you that not every user account has full access to that SYSTEM folder? You might want to pick a better place to put that database before you try and access it, like in the root of the Users profile or in the Temp folder. Even if all you're doing is querying the Access database and not making any changes to it, you still need full read/write permissions to the FOLDER that the .MDB file is in.

And for why it works on your dev machine and not on others - did you develop your app under an Admin account?? Not a good idea - even though most developers do this...

Dave Kreskowiak
Microsoft MVP - Visual Basic

Nafiseh Salmani21-Dec-06 23:19

Invoking events on a different thread...

21-Dec-06 23:19

both computer have the same os , and i login as admin in both computer so it is not for permission .

Shy Agam19-Dec-06 22:03

19-Dec-06 22:03

Hi,

I have a class which uses async sockets functions (i.e. BeginXXX).
One of the functions in my class for example is Listen().
In my callback functions I would like to fire events.
These events could sometimes be used to control the UI.
So what I'm looking for is a way to invoke the events on the calling thread instead of the callback's thread.
I thought of holding a reference to a Control object inside my class.
This reference would be sent to my class through the constructor, and I could then call Invoke() on it.
But what if its not a Control which called my Listen() function?

Is there any way to know which thread is the calling thread, and invoking the events on it?

Thanks in advance,
Shy.

Tristan Rhodes20-Dec-06 0:41

20-Dec-06 0:41

Hi Shy,

You can't really invoke the callback function on the calling thread, as that would have to be invoked Synchronously.

I'm assuming the reason you are trying to do this is because you can only manipulate GUI components from the thread they were created on (Static compartment). If this is the case, then you don't need to worry about using the calling thread to throw the events.

Instead, raise the events, and supply a delegate to the application Form, Form.Invoke(myDelegate)

This will run whatever code you need executing on the forms creating thread which will do any UI manipulations you need.

If that's not what you wanted, shout back and i'll have another look.

Tris

Shy Agam20-Dec-06 2:16

20-Dec-06 2:16

Tristan Rhodes wrote:
Instead, raise the events, and supply a delegate to the application Form, Form.Invoke(myDelegate)

Hmm... Not really sure what you mean...
Could you please give me an example?

In the meanwhile, I did the following, but I'm not really sure this is the right way:

class TCPSocket
{
    public event ConnectedEventHandler Connected;

    private Control user;

    public TCPSocket(...) { ... }

    public TCPSocket(..., Control user)
    {
        ...
        this.user = user;
    }

    private void RaiseConnectedEvent(IPEndPoint ep)
    {
        if (Connected != null)
        {
            if (user != null)
                user.Invoke(Connected, ep);
            else
                Connected(ep);
        }
    }
}

In my callbacks I use my RaiseXXXEvent() methods.
So basically this is how I invoke all of my events...
I'd be glad to hear your opinion about my code... Smile | :)

Is there something wrong with what I'm doing?

Tristan Rhodes20-Dec-06 2:30

20-Dec-06 2:30

Hi Shy,

I think the layouts a bit skewed.

You shouldn't really need to supply the control if the control can subscribe to the event.

try just using:

<br />
	private void RaiseConnectedEvent(IPEndPoint ep)<br />
	{<br />
		if (Connected != null)<br />
		{<br />
		Connected(ep);<br />
		}<br />
	}<br />

Then subscribe the relevant form to the event

<br />
class MyForm<br />
{<br />
	TCPSocket socket;<br />
	Control myControl;<br />
<br />
	// Handles socket.Connected event<br />
	private void SocketEventHandler(object sender, SocketEventArgs e)<br />
	{<br />
    // Handle Here (This will run on the executing thread NOT the GUI thread)<br />
<br />
    // Add the RunGuiThing delegate to the form invoker, this will<br />
    // run the desired delegate on the form / control creation thread.<br />
    me.Invoke(RunGuiThing);<br />
  }<br />
<br />
// GUI Handler<br />
  private void RunGuiThing()<br />
  {<br />
    // Update GUI control things here (This will be run on the GUI thread)<br />
    myControl.BackgroundColor = Color.Green;<br />
  }<br />
}<br />
<br />

Hope that solves it

Tris

Shy Agam20-Dec-06 2:37

20-Dec-06 2:37

Indeed, that is possible.
I just thought I'd add a built in functionallity to invoke the events on the GUI thread.

Tristan Rhodes20-Dec-06 3:10

20-Dec-06 3:10

Ah!

In that case - this should work:

<br />
class TCPSocket<br />
{<br />
    public event ConnectedEventHandler Connected;<br />
    <br />
    private Control user;<br />
<br />
    public TCPSocket(...) { ... }<br />
<br />
    public TCPSocket(..., Control user)<br />
    {<br />
        ...<br />
        this.user = user;<br />
    }<br />
<br />
    // Handles the Socket.Connected event<br />
    private void RaiseConnectionEvent(IPEndPoint ep)<br />
    {<br />
        if (user != null)<br />
          user.Invoke(this.Invoker, new object[]{ep});<br />
        else<br />
          this.OnRaiseConnectedEvent(ep);<br />
    }<br />
    <br />
    // Event Initializer<br />
    protected virtual void OnRaiseConnectedEvent(IPEndPoint ep)<br />
    {<br />
        if (Connected != null)<br />
        {<br />
          Connected(this, ep);<br />
        }<br />
    }<br />
    <br />
    // Invoker function to supply as a delegate<br />
    private void Invoker(IPEndPoint ep)<br />
    {<br />
        OnRaiseConnectedEvent(ep)<br />
    }<br />
}<br />

Tris

Shy Agam20-Dec-06 3:23

20-Dec-06 3:23

Hmm...

Why do we need the proxy Invoker() method?
user.Invoke() can accept an event as the 1st parameter, so why send it a function which raises the event?

Am I missing something here? D'Oh! | :doh:

Tristan Rhodes20-Dec-06 3:35

20-Dec-06 3:35

Hmm, didn't know that, but it makes sense. Smile | :)

I think the delegate route makes it more flexible if you want to add info in the EventArgs with details about the executing thread.

I'm not actualy sure what you're asking, the origional version would have worked, so what is the problem?

Tris

Shy Agam20-Dec-06 3:47

20-Dec-06 3:47

Well, I just wanted an opinion on my code, as I wasn't sure it's a good practice to send a Control object to the constructor. Smile | :)

I think I'll hold a reference to System.ComponentModel.ISynchronizeInvoke instead of a Control object, so it would be more generic...

Anyway... Thank you very much! Smile | :)

Much appreciated!

Tristan Rhodes20-Dec-06 3:56

dll getting updated on clients

20-Dec-06 3:56

Cool, np.

Good luck, let me know how it all ties up.

T

fmardani19-Dec-06 22:02

fmardani

19-Dec-06 22:02

Hi,
There is a project with classes (businessLayer) referenced from the clients (WinForms) project. So the BusinessLayer dll is sitting on the client. What happens if the businessLayer changes in the future? How will the clients pick up the new dll?
Please note that for business purposes this is how the solution is setup.
Thanks

AxShockwaveFlash

Nafiseh Salmani19-Dec-06 21:59

19-Dec-06 21:59

i use AxShockwaveFlashObjects in VS.net 2003 , but when i run the exe of this project , on framework 2 , this object cause error!!!!!!!!

why?
how could i solve this problem!!!

flash object

Nafiseh Salmani19-Dec-06 21:49

19-Dec-06 21:49

I use AxShockwaveFlash object in C# , and when the user click the right button of mouse on it , he/she can see the flash menu ,how could i hide this menu?

Re: flash object

althamda19-Dec-06 23:07

althamda

19-Dec-06 23:07

Put Stage.showMenu = false; in the first frame of your flash.

Re: flash object

Nafiseh Salmani19-Dec-06 23:35