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I always think of Exception Handling as a two step process;
1. There are going to be exceptional circumstances under which errors occur, which, due to good analysis, testing or experience can be handled at a reasonably low level. I usually consider database access as good example of this as the availability of the database should be considered outside of the scope of control of any DAL, (Data Access Layer), BLL, (Business Logic Layer), or UI.
2. In a project of any size there is usually going to be unpredictable responses to certain actions, some of which will generate exceptions and the reality is you simply cannot, (and should not), attempt to protect every method, event handler etc. within an Exception Handler. However, should an unpredicted, or unpredictable exception occur an application should handle it gracefully and take appropriate action based on the exception type, which as a programmer it is your job to consider.
My approach is typically to protect more sensitive and/or predictable area's of code with explicit exception handlers, but then to also attempt to protect an application at run time so that anything exceptional/unpredictable occurring is logged appropriately and potentially reported to the end user. The granular try...catch approach is obviously self explanatory, but the high level approach I normally undertake with an ExceptionManagement class which when instantiated subscribes to the '' and '' events and which itself can be configured at instantiation to tog or report handles exceptions in a predefined manner;
public class ExceptionManager : IDisposable
{
public ExceptionLogger()
{
Application.ThreadException += new System.Threading.ThreadExceptionEventHandler(OnThreadException);
AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(OnUnhandledException);
}
}
static class Program
{
internal const string C_ExecutingApplicationName = "My Application Name";
private static Form mainForm;
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
AppDomain.CurrentDomain.SetPrincipalPolicy(System.Security.Principal.PrincipalPolicy.WindowsPrincipal);
ExceptionManager exceptionManager = ExceptionManager();
ExceptionManager exceptionManager = new ExceptionManager();
mainForm = new Forms.Main();
Application.Run(mainForm);
}
}
Rhys
"With no power comes no responsibility"
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Hi all
can any one help me to create a datetimepicker which selects multiple dates from the calendar control(windows form application).
thanks
ajith
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The datetime picker supports on 1 selected item not a collection of selected items. There are some calendar controls out there that may support this but the standard DTP does not.
Never underestimate the power of human stupidity
RAH
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The MonthCalendar will let users select a range of dates. Not sure if that will help.
Creating your own dropdown control! Once you start dealing with the dropdown overhanging the form and whether there is enough room at the bottom of the desktop, loss of focus etc. You'll wish you hadn't. It's a coders nightmare.
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Creating a whole control is a bit beyond what anyone can do in a forum response. If you look through Code Project, you should be able to find a few articles that can help.
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My requirement is print a message in inside of rectangle in windows form application and I achieved this one using PrintDocument and PrintDialog control.I have written the code as shown below:
private void printDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
{
Rectangle rect = new Rectangle(50, 40, 500, 150);
e.Graphics.DrawRectangle(Pens.Black, rect);
RectangleF recf = new RectangleF(55, 45, 400, 20);
e.Graphics.DrawString("Printing from Windows form",new Font("Arial",10,FontStyle.Bold ), Brushes.Black, recf);
}
My problem is If I print this message using the above code.I got the some junck line along with message but the rectange is not drawn in the print document.
The following are the output from the printer(which lines bold )
/languagelevel where {pop languagelevel} {1} ifelse dup 2 ge {currentglobal ex
0 0 10 6 [] 0 1 GpPBeg
0.0039 0.0039 0.0039 SC
NP Printing from Windows form
300 240 m 3300 240 1 330 1140 1 300 1140 1 CP
S
GSE
If I print the same message without rectangel I am able to print correct message without junk lines (above bold lines).
I am using this printer model HP LaserJet M3027 MFP PCL 6 for print
Could you please help me how to fix this issue?
I am a software Developer and have worked on Microsoft .Net technologies for about 3 Years.I always interested to read the technical articles and learn about new technologies.
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ragupathi.p wrote: /languagelevel where {pop languagelevel} {1} ifelse dup 2 ge {currentglobal ex
0 0 10 6 [] 0 1 GpPBeg
0.0039 0.0039 0.0039 SC
NP Printing from Windows form
300 240 m 3300 240 1 330 1140 1 300 1140 1 CP
S
GSE
That stuff is raw PostScript code, the language used between your PC and your particular printer. Normally the printer interprets this textual information and only prints what is intended to be printed; the remainder being formatting, positioning, etc. (actually PostScript is a pretty complete programming language).
If you're saying the text shows as intended when only e.Graphics.DrawString() is present, and everything gets messed up when you do
e.Graphics.DrawRectangle(Pens.Black, rect);
e.Graphics.DrawString("Printing from Windows form",new Font("Arial",10,FontStyle.Bold ), Brushes.Black, recf);
then something is rotten, and it ain't your C# code. However I can't tell you what it is. Check your printer driver, does it match your printer? is it up-to-date? check your cable. Reset your printer and reboot your PC. If the mess is identical every time, it must be a bug. Experiment a bit with more lines of text, with different coordinates, fonts, whatever. Assuming nothing gives any improvement, start googling.
FWIW: if you need more proof your C# code is good, try printing to another printer. Maybe install a "PDF writer" which basically is a driver that emulates a printer and creates a PDF document, which you then can see on your screen. It will look all right!
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Thanks for your help.
As you suggested,I am able to print this message with rectangle using PDF Printer writter.
I am a software Developer and have worked on Microsoft .Net technologies for about 3 Years.I always interested to read the technical articles and learn about new technologies.
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Is it legal for a .NET 2.0 executable (.exe) to have a reference to a .NET 4.0 library (.dll)?
When I try this, the compiler complains that it can't resolve any of the types that come from the library.
As soon as I change the exe to .NET 4.0, the errors go away and it compiles cleanly.
Any thoughts? Thanks.
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I don't think you can do that, officially a process can run only one version of .NET so it should all be consistent. In reality AFAIK there is some leniency amongst 2.0, 3.0 and 3.5 as they are all built on top of 2.0
FWIW: In practice I only build for 2.0 (maximum audience), 3.5 (good audience/functionality mix), or 4.0 (max functionality).
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Thanks, Luc, I appreciate your help.
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You're welcome.
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Luc is correct. You can't use a 4.0 library from a 2.0 .EXE.
But, the reverse is possible. You can use a 2.0 .DLL in a 4.0 process. Starting with .NET 4.0, you get a little feature called "In-Process Side-by-Side Execution". Read more about it here[^].
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Thanks Dave. I can't tell you how long I operated under the mistaken assumption that you could mix runtime versions within a process.
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I have not tried with version 4.0, but I successfully referenced some .NET 3.0 dlls in Visual Studio 2005 projects.
But though C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\v3.0\PresentationCore.dll shows a "v3.0" in the path name, its runtime version shown in Visual Studio is v2.0.50727 - which might cause a difference in behavior when compared to a .NET 4.0 dll.
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hey guys..i want develop a program which will connect a website and it will save the some results in it..i found an example for it but there the developer import a dll to use some facebook features in his project..but in the site i want my program to connect has not such dll..so how i can get that results over the site ??
vemedya.com
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It really depends on what site you are trying to get data from, but if it was a general purpose site, you could consider using screen scraping.
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i will try to get it from a lottery site
the results of the lottery i mean
but it is not open source site..so how i can get it from the site ?
and what u mean screen scraping ?
vemedya.com
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What does Google tell you about screen scraping? Now that I've given you a hint as to what topic to look for, it's time for you to hone your researching chops.
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I disagree that screen scraping would be a good solution for quering a web site, especially if you have access to a HTML content. I would take it as a last choice and only if I had nothing but a screen, which I can barely imagine.
Greetings - Jacek
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Screen scraping is also a term used to describe scraping content from a website, especially as he has already said he doesn't have an API available, and that there's no guarantee that the site is XHTML compliant.
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I hate to argue on terminology, but I suppose you meant web scrapping[^]. The site does not really have to be XHTML compilant to query it (e.g. when using the library I mentioned in my another post).
Ehm, whatever. Have a nice day/night or whatever currently is present in your time zone.
Greetings - Jacek
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Jacek Gajek wrote: I suppose you meant web scrapping[^].
I stand (well sit actually) corrected. I've run into problems attempting scraping with Html Agility Pack in the past, so have tended to avoid it. Newer versions might have improved it somewhat. Have a 5 to correct whoever 2 voted it.
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Pete O'Hanlon wrote: Have a 5 to correct whoever 2 voted it.
Thanks. It looks like you have a devoted fan who cannot stand watching you being corrected.
Greetings - Jacek
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