C# Discussion Boards - CodeProject

Regardt13-Jan-04 2:54

13-Jan-04 2:54

Hi

I would really appreciate it if anybody can help me!! I must convert a HTML page ..images include into a PDF file and stream the PDF file into a DB.

I have searched the net without any real success.

Thanks

Regardt

Africa is a though country
--"Hello daar vir die Afrikaans sprekende"--

Re: Convert HTML to PDF Stream into DB

Alex Korchemniy13-Jan-04 4:48

Alex Korchemniy

13-Jan-04 4:48

You have to split this up into two part. First convert then encode and send to server.

Take a look at this site: http://www.verypdf.com/ and see PDFcamp/PDFwriter - it looks like this is the least expensive way of converting html to pdf. If you are looking for more pro components then around at: www.pdfstore.com (Some of the prices out there are scare if you are a startup and dont have much money.)

To put the pdf in database just read the file in and use Convert.ToBase64String() and send it to the database.

Re: Convert HTML to PDF Stream into DB

Heath Stewart13-Jan-04 5:32

Heath Stewart

13-Jan-04 5:32

You could also - depending on the RDBMS - store the PDF as a binary stream, which some ADO.NET classes (like those in System.Data.SqlClient) support. IMO, you should store the PDF on the filesystem and either store the path in the DB or use the primary key as part of the filename, which is what we do in our flagship product.

-----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-----

Custom permissions

Hans Ruck13-Jan-04 1:43

Hans Ruck

13-Jan-04 1:43

I'm using the ".NET Configuration Tool" to change the properties of the permissions belongin' to various permission sets. This can be done using the "Properties" dialog available for any built-in permission.

Is there any way to provide such a dialog for a custom permission, a CodeAccessPermission-derived class? The default displays a message like "The Custom Permission is unrestricted", or an xml fragment Dead | X|

rechi

Re: Custom permissions

Heath Stewart13-Jan-04 5:30

Heath Stewart

13-Jan-04 5:30

The mscorcfg.dll assembly for the Microsoft .NET Framework Configuration snap-in is hard-coded to display views and property pages for the built-in permission classes and all the abstract classes are marked private. There is nothing in the .NET base class library for this either, unfortunately. You could take a look at the aforementioned assembly to see if there's any other hooks or interfaces, but it doesn't appear to have any.

Re: Custom permissions

Hans Ruck13-Jan-04 22:21

Hans Ruck

13-Jan-04 22:21

Thank you! Smile | :)

rechi

axwebbrowser excel mdicontainer

mylitziname12-Jan-04 22:28

mylitziname

12-Jan-04 22:28

If I open a form with a axwebbrowser-control in a mdi-container
and show an excel-sheet in the webcontrol, than close the form
and application, the excel-process leaves alive.
If I close the application without closing the form first
excel closes.

Help appreciated.

Litzi

Re: axwebbrowser excel mdicontainer

mylitziname12-Jan-04 23:24

mylitziname

12-Jan-04 23:24

Excel was closed when I used axWebBrowser1.Dispose()
in the closing event from the form

Litzi

Environment variable

cfl12-Jan-04 22:03

cfl

12-Jan-04 22:03

Hello Gurus,

I am using Environment.GetEnvironmentVariable() method to retreive a value from a an defined environment variable in a Win2k machine.

This method is able to get the value from a console application mode. However, if I run my application in a window service mode. It fail to get any value from the same defined environment variable.

Is there any setting I need to perform? Any suggestion, please advise. Thanks.

Re: Environment variable

mylitziname12-Jan-04 23:33

mylitziname

12-Jan-04 23:33

maybe your service runs in an other environment (other user)
try to get for example >ver<

Litzi

Re: Environment variable

Heath Stewart13-Jan-04 5:15

Heath Stewart

13-Jan-04 5:15

The environment variable has to be a system environment variable, or a user environment variable for the user that the service runs as. Adding environment variables from the command-line are also only valid for that instance of the command line, or any programs started from the command line. To configure persistent, global environment variables, go to the Advanced tab of your System Properties (right-click on My Computer and select Properties) and click the Environment Variables button (or similar). You'll see sections for both user and system environment variables there.

Re: Environment variable

cfl13-Jan-04 15:42

cfl

13-Jan-04 15:42

Hello all,

Thanks for your advise. The problem solved. Thanks.

.NET version dependent compilation

brain2cpu12-Jan-04 21:09

brain2cpu

12-Jan-04 21:09

is there something like:

#if theCompilerVersionIs1.0
using Microsoft.Data.Odbc;
#else
using System.Data.Odbc;

??

I have VS2002 and have to command line compile for 1.1 and it would be great not to change my code for this.

Re: .NET version dependent compilation

Heath Stewart13-Jan-04 5:12

Heath Stewart

13-Jan-04 5:12

There is preproc conditions supported by the C# compiler, yes, but there is no such definitions provided by the compiler that are documented, so you'll have to pass them yourself using /d:SYMBOL or configuring additional symbols in your VS.NET project (go to project properties, expand Configuration Properties, click on Build, and add symbols to the Conditional Compilation Constants at the top). An example follows:

#if CSC10
using Microsoft.Data.Odbc;
#else
using System.Data.Odbc;
#endif

DragDrop to a native window?

TuringTest112-Jan-04 19:20

TuringTest1

12-Jan-04 19:20

does anyone know how to implement drag drop events in native windows? there doesn't seem to be any WM_DRAGDROP message!

related question, are the dotnet drag drop events into a control implemented by some object or code library that is accessible?

TIA!

________________________________________

Gosh, it would be awful pleas'n, to reason out the reason, for things I can't explain.
Then perhaps I'd deserve ya, and be even worthy of ya..
if I only had a brain!

Re: DragDrop to a native window?

Heath Stewart13-Jan-04 5:07

Heath Stewart

13-Jan-04 5:07

Drag and drop is not trivial to implement. .NET exposes this in a rather easy-to-use method that encapsulates all the native functions, interfaces, structs, and enums/constants. As you can see, though, not every control in .NET supports drag and drop, either. There is a lot that has to be done in order to do this for native windows. There is more documentation in the Platform SDK at http://msdn.microsoft.com/library/en-us/dnanchor/html/anch_WinShell.asp[^]. Specific interfaces and functions to look at are IDropSource, IDropTarget, IDataOject, and DoDragDrop. These are all from the Platform SDK, not the .NET Framework SDK (I only mentioned because a couple of these have similarly named equivalents in both). Those four interfaces and functions - along with the documentation about them - should be enough to get you started.

On a side note, so long as the clipboard formats are supported by both the drag source and the drop target - regardless whether either one is managed or native - and the data is formatted correctly you can drag and drop between windows.

Finally, if you are looking to add drag-n-drop support to your native Windows, first read about the Windows Shell and drag-n-drop interfaces from the link I gave you and continue in the Visual C++ or ATL/WTL/STL forum.

Re: DragDrop to a native window?

TuringTest113-Jan-04 5:55

TuringTest1

13-Jan-04 5:55

Heath, thank you for the great references (as usual!).

________________________________________

Gosh, it would be awful pleas'n, to reason out the reason, for things I can't explain.
Then perhaps I'd deserve ya, and be even worthy of ya..
if I only had a brain!

asking for system tray application

azusakt12-Jan-04 16:25

azusakt

12-Jan-04 16:25

Hello,

I would like to improve my application; hope it can minimize to system tray, and appear again if double clicked on system tray icon.
I know I should use notify icon, but how can I catch the minimize event of my application and tell it to minimize to system tray?

I just hope to find a good example of using notify icon, could any one help and teach me?

Thank you

Re: asking for system tray application

Jeff Mackie12-Jan-04 17:16

Jeff Mackie

12-Jan-04 17:16

azusakt,

Well it may seem that the application is actually minimizing into the system tray. But what happens is that when you minimize your application you actually hide it. Then when you double click on the notify icon, you show the application in its normal state.

// This hids the application when Minimized. (Forms resize event)
private void frmMain_Resize(object sender, System.EventArgs e)
{
if (this.WindowState == FormWindowState.Minimized)
{
this.Hide();
}
}

// Show the application when doubleclick event happens (Icon Try Double Click Event)
private void nicTray_DoubleClick(object sender, System.EventArgs e)
{
this.Show();
this.WindowState = FormWindowState.Normal;
}

Hope this helps.

Re: asking for system tray application

azusakt12-Jan-04 17:51

azusakt

12-Jan-04 17:51

Thanks for you reply Jeff,

I've done something like your code, and it works, but a little bit strange effect. I set the form's ShowInTaskBar property to false, and I used:

private void notifyIcon1_DoubleClick(object sender, System.EventArgs e)
{
     this.Show();
     this.WindowState = FormWindowState.Normal;
     this.notifyIcon.Visible = false;
}

private void ProgressBarForm_SizeChanged(object sender, System.EventArgs e)
{
     if(this.WindowState == FormWindowState.Minimized)
     {
	this.Hide();
	this.notifyIcon.Visible = true;
     }
}

It works like your expection, but the visual effect looks strange,; it firstly minimized to left bottom corner and then hide, that means always flash to left corner and then restore. How can I minimize it directly to system tray?

Re: asking for system tray application

Heath Stewart13-Jan-04 4:53

Heath Stewart

13-Jan-04 4:53

Through so much unbelievable math it's not even funny! Smile | :)

The minimization effect is handled by the Windows, not the application. You have to dig very deep into Windows to override that behavior (if possible) and do all the math yourself to draw the minimizing Window compacting and moving toward the systray icon. I've never seen an application do this - not even from Microsoft.

What I do so most often to combat this effect is to hide the window first, then minimize, or vice-versa to restore (restore then show). This way, you don't see the Window minimize and don't have to worry about such behavior (which I agree looks odd).

returning when inside a lock - is it safe?

Brandon Haase12-Jan-04 15:29

Brandon Haase

12-Jan-04 15:29

I've run into a situation I haven't seen before, and was wondering if someone with a bit more threading experience would like to chime in.

The class IsoCurrencyInfo maintains a collection of IsoCurrencyInfo singletons. The instances of IsoCurrencyInfo class themselves are read-only once created, so by themselves are thread-safe. The trick is keeping the ArrayList container in line. I think I have it nailed, but in doing so I am executing a return statement while inside a lock().

The code works very well under heavy concurrent load Cool | :cool:

, but I can't help wondering "Is this safe?" Is there a better way to structure this method to optimize the locking?

I have adapted the Singleton implementation pattern[^] from Microsoft Patterns & Practices[^].

public static IsoCurrencyInfo GetInstance(string isoCode) 
{
	IsoCurrencyInfo newICI = null;

	if(null == _iciRegistry)
		lock(syncRoot) 
			if(null == _iciRegistry)
			{
				_iciRegistry = new ArrayList();

				newICI = new IsoCurrencyInfo(isoCode);
				_iciRegistry.Add(newICI);
			}
	if(null == newICI) 
		lock(syncRoot) 
		{
			foreach(IsoCurrencyInfo existingICI in _iciRegistry)
				if(existingICI.AlphaCode == isoCode)
					return existingICI;

			newICI = new IsoCurrencyInfo(isoCode);
			_iciRegistry.Add(newICI);
		}
	return newICI;
}

Thanks!
B

Re: returning when inside a lock - is it safe?

Heath Stewart13-Jan-04 4:46

Heath Stewart

13-Jan-04 4:46

It's completely safe. The lock keyword translates to the following (verifiable if you use ildasm.exe or some other disassembler / decompiler to view the compiled code):

Monitor.Enter(syncRoot);
try
{
  // Do stuff
}
finally
{
  Monitor.Exit(syncRoot);
}

The finally block is always run - regardless of a return or a throw - except when Environment.Exit is called (which unloads the process and the CLR completely, thus it really won't matter that the lock wasn't released because the OS will reclaim any process resources).

Re: returning when inside a lock - is it safe?

Brandon Haase13-Jan-04 16:13

Brandon Haase

13-Jan-04 16:13

Thank you for a solid example. I didn't think of checking my decompiler's output.

Re: returning when inside a lock - is it safe?

scadaguy13-Jan-04 5:23

scadaguy

13-Jan-04 5:23

Brandon,

Returning inside a lock is okay.

I don't necessarily see anything incorrect about your implementation. However, the double-checked locking pattern is essentially useless as you have used it since you'll always be aquiring at least one lock anyway. I would suggest the following code...

public class IsoCurrencyInfo
{
    private static Hashtable _iciRegistry = new Hashtable();

    public static IsoCurrencyInfo GetInstance(string isoCode)
    {
        if (!_iciRegistry.Contains(isoCode))
        {
            lock (syncRoot)
            {
                if (!_iciRegistry.Contains(isoCode))
                {
                    _iciRegistry.Add(isoCode, new IsoCurrencyInfo(isoCode));
                }
            }
        }
        return (IsoCurrencyInfo)_iciRegistry[isoCode];
    }
}

It is important to realize that the Hashtable is the only IDictionary collection that will work as I have used it. This is because the Hashtable can support multiple readers and one writer simultaneously. Likewise, you won't be able to use the same trick with an ArrayList. In this implementation the lock is rarely acquired.

Brian

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