Over ride closing event - C# Discussion Boards

30-Jan-04 3:34

This isn't going to solve your problem. You can't compile C/C++ code with the C# compiler! It's not just another language but a language that targets a completely different runtime! Learn the basics of programming first.

The .NET Framework is available from http://msdn.microsoft.com/netframework/[^]. Make sure you actually READ the documentation first - especially the "Getting Started" topics - before jumping into anything.

-----BEGIN GEEK CODE BLOCK-----
Version: 3.21
GCS/G/MU d- s: a- C++++ UL@ P++(+++) L+(--) E--- W+++ N++ o+ K? w++++ O- M(+) V? PS-- PE Y++ PGP++ t++@ 5 X+++ R+@ tv+ b(-)>b++ DI++++ D+ G e++>+++ h---* r+++ y+++
-----END GEEK CODE BLOCK-----

Security Issues

Ken Galer29-Jan-04 10:26

Ken Galer

29-Jan-04 10:26

I am working on a small project that I started at home. It originally was on the C: drive and was working properly. After bringing it to work I placed it in a folder on the server with the other projects folders and now it will not let me run.

I get a security exception:

/////
An unhandled exception of type 'System.Security.SecurityException' occurred in JC Test Fixture.exe
Additional information: Security error.
/////

I used the "Trust an Assembly" wizard and got the same error. I even adjusted the .net security to fully trust the intranet and it still complains.

Is there usually an issue when developing .net apps from a folder on an intranet folder?

The msdn info is very detailed and nearly useless.

Rebuilding the app didn't help, can I just delete some output files and rebuild? Which ones? OMG | :OMG:

Tx

Ken Galer
Electrical Engineer
Preferred Utilities Corp.
Danbury, CT 06810

Re: Security Issues

Heath Stewart29-Jan-04 13:16

29-Jan-04 13:16

There is most definitely an issue when running an assembly from the intranet. Code Access Security is a major feature of the CLR and this is often overlooked. The wizard you use is junk - don't use it. Learn about code access security and use the Microsoft .NET Framework Configuration snap-in and do it the right way.

In your case, you're using a method or class that requires a certain permissiont that is not granted to assemblies running in the Intranet zone. The wizard only collections assembly evidence instead of host evidence and so, if you're using automatic versioning (using the asterisk in the AssemblyVersionAttribute, which is a very BAD idea for so many reasons I can't believe they included it as a feature), the assembly evidence won't match what the wizard collected (because the version is different). Also, assembly evidence isn't always presented to the CLR, such as in the case of smart clients (assemblies executed in Internet Explorer). Code access security is an important feature to understand to avoid these cases and, preferably, use to your advantage to customize your application in case certain permissions are granted to your assembly/assemblies.

Fortunately, there was a great article posted on CodeProject about code access security not long ago: Understanding .NET Code Access Security[^].

You can also find more information about code access security and various permissions in the .NET base class library at http://msdn.microsoft.com/library/en-us/cpguide/html/cpconcodeaccesssecurity.asp[^].

Re: Security Issues

Ken Galer30-Jan-04 2:23

Ken Galer

30-Jan-04 2:23

Heath,
It's amazing that I just spend $1100 on CD training for .NET and I didn't hear one word about assembly security. I'll be sure to read that article that you mentioned.

It's equally amazing how cyptic of an answer I got from MS on their newsgroup.

I was able to get the Framework Configuration snap-in to work but only after I realized (after about 3 hours) that there were TWO versions to choose from on my machine. It looks like I was tweaking the one for Version 1.0. When I used the 1.1 version things started to make sense again. I made a new Code Group in Runtime Security Policy/Machine/Code Groups and made my mapped netword drive fully trusted.

You guys ever wonder why you do this stuff for a living?

Thanks

Ken Galer
Electrical Engineer
Preferred Utilities Corp.
Danbury, CT 06810

Re: Security Issues

Heath Stewart30-Jan-04 3:23

Re: Over ride closing event

30-Jan-04 3:23

Just go to show that the best material you can read is the .NET Framework SDK documentation - and it's free! I learned pretty much everything I know from that in the old 1.0 bata days and everything else is based on experience from that initial reading and checking out interesting code samples on sites like CodeProject.

Over ride closing event

Daniel Negron29-Jan-04 9:27

Daniel Negron

29-Jan-04 9:27

**NOOB**

I am over riding the closing event for the main form, Windows Shutdown process halts until the application is manually closed. Then I have to initiate the shutdown sequence again.
Below I have the OnClosing event. I am looking to combine the two below so that they close out the application if Shutdown, Restart or Logoff are initiated.

protected override void OnClosing(CancelEventArgs e)
{

e.Cancel = true;

this.WindowState = FormWindowState.Minimized;
Hide();
}

protected override void WndProc(ref Message m)
{
base.WndProc (ref m);
if (m.Msg == 0x0011)
{
Application.Exit();
//this.Close();
}
}
If I have these 2 methods in place, the application WILL shutoff, BUT it will also halt the shutdown process, and once again I have to start the shutdown process all over again.

Thank you in advance for your help.

**DAN**

Heath Stewart29-Jan-04 13:08

29-Jan-04 13:08

Calling Application.Exit sends the WM_QUIT message to the application, this the pump catches and the WM_CLOSE event is not (typically) called, so OnClosing is not executed. That much you've discovered. When handling the WM_QUERYENDSESSION notification message, though, you should set Message.Result = new IntPtr(1); in order to essentially return TRUE as the return value so that the shutdown process isn't canceled. By not setting this value, FALSE is essentially returned and the shutdown process is cancelled as you have noticed.

For more information, see the documentation for the WM_QUERYENDSESSION notification message at http://msdn.microsoft.com/library/en-us/sysinfo/base/wm_queryendsession.asp[^] and pay close attention the return value documentation and the remarks section. Hopefully this will help, but it won't combine those two handlers. Honestly though, it really doesn't matter - it solves the problem and that's what counts. Besides, the Closing event is triggered by the WM_CLOSE message which isn't sent to Windows unless the application pump handles an appropriate message and sends or posts the message itself (at least, from what I remember).

Listbox deleting items

Gavin Coates29-Jan-04 8:19

29-Jan-04 8:19

I seem to be encountering difficulty while trying to delete an item from a listbox. The user selects an item from the listbox, then clicks a delete button. The button code is as follows:

<br />
try<br />
{<br />
listBox1.Items.Remove(listBox1.SelectedItem);<br />
}<br />
catch(IndexOutOfRangeException ex)<br />
{<br />
 MessageBox.Show("Could not delete the selected item", "Error", MessageBoxButtons.OK);<br />
}<br />
<br />

Now, if I select the first item in the list, and press delete, the exception IndexOutOfRange occurs, however the item is then successfully deleted. If I select any other item in the list and try to delete it, it works fine, no exception

Why does deleting the first item cause an exception

Mazdak29-Jan-04 8:28

Mazdak

29-Jan-04 8:28

I test your code and there is no problem with that. It works properly for all items. Whats your error message?

Mazy

No sig. available now.

Gavin Coates29-Jan-04 9:09

29-Jan-04 9:09

i just get an "IndexOutOfRangeException" occuring. Im using Borland C# if thats any help?

Mazdak29-Jan-04 9:14

Mazdak

29-Jan-04 9:14

Gavin Coates wrote:
i just get an "IndexOutOfRangeException" occuring

Every exeptions have a Message property, which is string contained a error string.

Gavin Coates wrote:
Borland C#

Oh, I don't know about that. I haven't seen anybody use it here.

Mazy

No sig. available now.

Gavin Coates29-Jan-04 9:52

29-Jan-04 9:52

error is:

"Index was outside the bounds of the array"

thomasa30-Jan-04 0:45

thomasa

30-Jan-04 0:45

Try
private void btnDelTheListBoxItem_Click(object sender, System.EventArgs e)
{
if(TheListBox.SelectedItem != null)
{
for(int i = 0; i < TheListBox.Items.Count; i++)
{
if(TheListBox.SelectedItem.Equals(TheListBox.Items[i]))
{
TheListBox.Items.RemoveAt(i);
i = TheListBox.Items.Count;
}
}
}
}

This will work

Gavin Coates31-Jan-04 10:17

31-Jan-04 10:17

ggthanks thomasa.

I tried the code above, but again i get exactly the same results! I can delete any item in the listbox no problems, but when i try to delete the first item, it deletes, but causes an IndexOutOfRangeException!!

I tried creating a whole new project with just a listbox, textbox add and delete button, and it worked perfectly, no errors at all. It just causes problems in my current project!!!

Please help!

thomasa1-Feb-04 22:14

thomasa

1-Feb-04 22:14

Strange.
You should sett up some breakpoints and find out what index the first Item in your listbox has. It should have index 0.
It might be that you add the item to your listbox in a special way?
I use:
TheListBox.Items.Add("Some text");

Multi-threading

Guinness4Strength29-Jan-04 5:17

Guinness4Strength

29-Jan-04 5:17

What is the most efficient way to wait for a worker thread to complete. I'm making a file sending program and I want to only send one file at a time (i.e. wait for the previous send to finish), but I want the user thread to keep processing messages because I have status indicators and other options that need to be available while sending.

Re: Multi-threading

scadaguy29-Jan-04 10:23

scadaguy

29-Jan-04 10:23

Sounds like what you want is one dedicated thread that sits idle in an infinite loop waiting for files to send. Each send request would be enqueued into a blocking queue. The dedicated thread wakes up when an item is available in the queue and processes it accordingly.

Re: Multi-threading

Guinness4Strength29-Jan-04 10:27

Guinness4Strength

29-Jan-04 10:27

Thanks for the reply,
I was thinking too hard, I solved the problem with a single boolean value that I set when I begin and end a send thread, the user thread just check the value of the boolean...somtimes its too easy to see.

Re: Multi-threading

Heath Stewart29-Jan-04 12:55