Re: Windows application - C# Discussion Boards

Re: No value given for one or more required parameters.

19-Oct-09 13:41

Hi,

I haven't done this with Excel but here are my thoughts anyway:

- if "SELECT * ..." works fine, then your connectionstring, DB path, etc. are fine;
- so the problem must be in one or several of the field names

Hence: start with one field, then add them one by one until it fails; fix that, and keep adding till done.

BTW: I would never choose complex field names with spaces, dollars, etc; it only complicates matters. However escaping them would solve everything, I am not absolutely sure square brackets is the right way, I found at least one web page claiming backquotes should be used. Once more, experiment with a single column first.

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Local announcement (Antwerp region): Lange Wapper? 59.24% waren verstandig genoeg om NEEN te stemmen; bye bye viaduct.

_Maxxx_20-Oct-09 19:12

_Maxxx_

20-Oct-09 19:12

I really have no idea with excel, but:

If the Select * works fine, then examine the datarow(s) returned and find the name(s) of the columns returned - that will show you what names of columns you need to use in your select statement.

Try reducing the first Select to just returning one column - if that works add the next column and keep going until it breaks.

My suspicion is that the excel data provider is not using the first row for column names, hence it can't find them in your first query - so you need to find out how to tell it to treat the first row as names of columns.

Good Luck

Max

___________________________________________
.\\axxx
(That's an 'M')

Windows application

or or19-Oct-09 11:34

or or

19-Oct-09 11:34

I wrote a windows application witch should run always - from turning on the computer until it goes off. When I try to shut down the computer sometimes it doesn't turn off. My OS is Windows-XP.
(I have some threads but all of them are background threads.)

Eddy Vluggen19-Oct-09 11:54

Eddy Vluggen

19-Oct-09 11:54

You're cancelling the FormClosing[^] event? Take a look at the CloseReason; you might want to allow the closing of the form when the CloseReason is CloseReason.WindowsShutDown Smile | :)

I are Troll Smile | :)

or or19-Oct-09 20:24

or or

19-Oct-09 20:24

Thanks, you're right I did cancel the close.

Not Active19-Oct-09 13:15

19-Oct-09 13:15

If you want an application to run from start to end like this you should use a Windows service, not a Windows form application, then you won't have this issue.

only two letters away from being an asset

Magical thread? [modified]

or or20-Oct-09 0:06

or or

20-Oct-09 0:06

Thanks for your help.
Now I got some error/strange window with caption:
.Net-BroadcastEventWindow.2.0.0.
What does it mean?
Thanks.

Scalee19-Oct-09 10:42

Scalee

19-Oct-09 10:42

I want to remove a bottleneck using a second thread, but my thread dies but the object lives on..
So i don't seem to understand whats going with my thread let me try to explain:

Starter code:

<br />
            //new thread object (thread declared as Thread msnthread;)<br />
            //create the new thread with a threadstart pointing to StartMSN<br />
            msnthread = new Thread(new ThreadStart(StartMSN));<br />
            //Start the thread<br />
            msnthread.Start();<br />

Function code:

<br />
       private void StartMSN()<br />
        {<br />
            //start label<br />
            start:<br />
                try<br />
                {<br />
                    //check if msn is running if not abort<br />
                    if (Process.GetProcessesByName("msnmsgr").Length != 0)<br />
                    {<br />
                        //New msn class object (declared as MSN Msnclass;)<br />
                        Msnclass = new MSN();<br />
                        //Add an event handler and point it to this.Cout<br />
                        Msnclass.Cout += new MSN.cout(Cout);<br />
                    }<br />
                    else<br />
                    {<br />
                        //Sleep for 10 seconds and retry<br />
                        Thread.Sleep(10000);<br />
                        goto start;<br />
                    }<br />
                }<br />
                catch (Exception e)<br />
                {<br />
                    //on crash print error and sleep for 10 seconds<br />
                    Cout("Fatal error: \n" + e.Message);<br />
                    Thread.Sleep(10000);<br />
                    //goto start label and recreate object<br />
                    goto start;<br />
                }<br />
        }<br />

After this code has run, the thread dies but the Msnclass keeps alive, but is it still threaded??
What am i doing wrong, also what would be a better way to restart instead of the goto start?

Thanks!

modified on Monday, October 19, 2009 6:23 PM

Re: Magical thread? [modified]

Luc Pattyn19-Oct-09 11:39

19-Oct-09 11:39

Hmm.

[EDIT]a finally block would always execute, resulting in one sleep too many. fixed that with a variable delay which also makes the finally block unnecessary
[/EDIT]

the normal way for retrying something is by setting up a loop which gets exited on success only. For instance:

for(int delay=0; ; delay=10000) {
    Thread.Sleep(delay);
    try {
        ...
        break; // or return
    } catch(...) {
        ...
    }
}

so no goto's, and a single sleep.

Scalee wrote:
Msnclass.Cout += new MSN.cout(Cout);

I'm puzzled by this statement. Not sure what the intention is.
I'm pretty sure the cout should be a Cout (public identifier ==> PascalCase).
And it would be my guess cout() never returns for some reason.
suggestion: add a log statement right behind it; if that never executes, look at cout().

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Local announcement (Antwerp region): Lange Wapper? 59.24% waren verstandig genoeg om NEEN te stemmen; bye bye viaduct.

modified on Monday, October 19, 2009 6:00 PM

Scalee19-Oct-09 12:23

Scalee

19-Oct-09 12:23

Aah no :P

You can ignore Cout it's an event, i can fire the event from the Msnclass and send messages to my main class to be printed Wink | ;)

The thing still is that my thread dies and my object keeps existing which should be impossible...

Ill add some comments to the main thread if i still can.

Luc Pattyn19-Oct-09 12:43

19-Oct-09 12:43

OK,

I read it again, here are some comments and suggestions:

1.
please use PRE tags, not CODE tags, for showing multi-line code snippets.

2.
//check if msn is running if not abort isn't really accurate, as nothing gets aborted, something gets retried instead.

3.
assuming Cout(string) logs or somehow shows a string, add a Cout("going to create MSN"), a Cout("done creating MSN") and Cout("going to sleep") at the appropriate places. That way you will easily see what goes on.

4.
I expect you'll see the "going to create MSN" but no "done creating MSN", as the only location the loop can hang seems to be inside the MSN constructor, for reasons unknown as you didn't show its code.

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Local announcement (Antwerp region): Lange Wapper? 59.24% waren verstandig genoeg om NEEN te stemmen; bye bye viaduct.

Scalee19-Oct-09 21:39

Scalee

19-Oct-09 21:39

Nope, there is no hanging.

This is how the application should be:

Main thread > running > mainform
Msn thread > running > msn class

What it is:

Main thread > running > mainform
Msn thread > stopped > msn class

Yet the class is still alive and usable, this is how i checked it:

//Code run on toolstrip opening event:

//returns Stopped
toolStripMenuItem6.Text = "Msn status: " + msnthread.ThreadState.ToString();

//Clear subitems
toolStripMenuItem6.DropDownItems.Clear();

//Now if my thread is gone so should be the Msnthread object, however i can still access it here
foreach (MsnWindow win in Msnthread.MsnWindows)
{
    toolStripMenuItem6.DropDownItems.Add(string.Format("{0} {1} {2}", win.Name, win.History.ToString(), win.Window.HWND));
}

Luc Pattyn20-Oct-09 1:36

Visual Studio managing my project files

20-Oct-09 1:36

So there is no problem at all:
the MSNstart method has run to completion, hence the thread is stopped.
and the MSN object may be collectible (if no reference got stored somewhere by its constructor), and hence could possibly be collected by the GC the next time it runs.

Hmmm | :|

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Local announcement (Antwerp region): Lange Wapper? 59.24% waren verstandig genoeg om NEEN te stemmen; bye bye viaduct.

LimitedAtonement19-Oct-09 9:59

19-Oct-09 9:59

Dear Sirs,

I need my project files to go to the right place. I currently have three projects. Project A depends on Projects B and C, both Class Libraries. Project B has a database file (MDB) in it, which copies properly to Project A's output (either Release or Debug \data) directory. Project C, however, the rogue, has a file in it and it copies to project C (!!)'s output folder. How do I get Project C to cooperate, and send its file (an XNA font file) to Project A working directory?

I wouldn't mind so much Project C copying its Content files to its own directory, but it can't find them from there: when the program runs, Project C uses Project A's active directory, so Project C complains, I can't find my file. I look around, and in Project C's directory, there it is, but the Exception says that it's looking in Project A's active directory.

I hope I have been clear enough. Thanks in advance for your help.

In Christ,
Aaron Laws

In Christ,
Aaron Laws

http://ProCure.com

Not Active19-Oct-09 10:08

19-Oct-09 10:08

In Project C's properties, go to Build Events tab and use a post-build event command to copy the files to the necessary location.

only two letters away from being an asset

LimitedAtonement19-Oct-09 10:14

19-Oct-09 10:14

Dear Mr. Nischalke,

Thank you for your prompt reply. I noticed, however, that Project B (the working project which properly copies its database) doesn't have what you described. Why can Project B work and not Project C?? I'll try your suggestion.

In Christ,
Aaron Laws

http://ProCure.com

Not Active19-Oct-09 10:25

19-Oct-09 10:25

I can only assume that VS know to copy the file as a dependency when you add a reference to the project. The properties of the file are probably set to copy to output.

only two letters away from being an asset

LimitedAtonement19-Oct-09 10:52

19-Oct-09 10:52

Dear Mr. Nischalke,

Thanks for you help. In both projects, B and C, the files in question are set to

Build action              |    Content
Copy to output directory  |    True

In Christ,
Aaron Laws

http://ProCure.com

Not Active19-Oct-09 11:03

19-Oct-09 11:03

If you want further help, drop the Mr. Poke tongue | ;-P

I've used commands like this to move files within my project folder structure

copy "$(TargetDir)$(TargetFileName)" "../../../Common/$(TargetFileName)"

only two letters away from being an asset

Alan N19-Oct-09 10:31

Alan N

19-Oct-09 10:31

Hi,
Dll files may be copied to the output directory by setting the Copy Local property of the reference (right click the appropriate reference in solution explorer).

In general any file may be copied by right clicking, selecting properties and setting the Copy to Output Directory property.

Alan.

Not Active19-Oct-09 10:40

19-Oct-09 10:40

All well and good but this doesn't help his problem. This will place the files in the bin folder of the project, not copy them to another location, such as another project's output folder.

only two letters away from being an asset

LimitedAtonement19-Oct-09 10:54