C#

John Simmons / outlaw programmer wrote:

It seems to me that there must be a way to create a centralized exception handler and reduce the number of try/catch blocks overall.

using System;
using System.Security.Permissions;

public class Test {

   [SecurityPermission(SecurityAction.Demand, Flags=SecurityPermissionFlag.ControlAppDomain)]
   public static void Example()
   {
      AppDomain currentDomain = AppDomain.CurrentDomain;
      currentDomain.UnhandledException += new UnhandledExceptionEventHandler(MyHandler);

      try {
         throw new Exception("1");
      } catch (Exception e) {
         Console.WriteLine("Catch clause caught : " + e.Message);
      }

      throw new Exception("2");

      // Output:
      //   Catch clause caught : 1
      //   MyHandler caught : 2
   }

   static void MyHandler(object sender, UnhandledExceptionEventArgs args) {
      Exception e = (Exception) args.ExceptionObject;
      Console.WriteLine("MyHandler caught : " + e.Message);
   }

   public static void Main() {
      Example();
   }
}

static void Main()
{
    Application.ThreadException += new ThreadExceptionEventHandler(Application_ThreadException);

    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);
    Application.Run(new Form1());
}

static void Application_ThreadException(object sender, ThreadExceptionEventArgs e)
{
    // Check and recover from the exception if possible
    
    // Notify user and exit application if can't recover
}

Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException);

static void Application_ThreadException(object sender, ThreadExceptionEventArgs args)
        {
            // Check and recover from the exception if possible        
            // Notify user and exit application if can't recover

            Exception e = (Exception)args.ExceptionObject;  // Not supported above .NET 3.5!!
            MessageBox.Show(args.ToString());
        }

ThreadExceptionEventArgs Class  

Provides data for the ThreadException event. 


Namespace:   System.Threading
Assembly:   System (in System.dll) 

...

PlatformsWindows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98



The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements. 
Version Information.NET Framework
Supported in: <big>3.5, 3.0, 2.0, 1.1, 1.0</big> 

public class ExceptionManager : IDisposable
{
    // Some code...

    public ExceptionLogger()
        {
            Application.ThreadException += new System.Threading.ThreadExceptionEventHandler(OnThreadException);
            AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(OnUnhandledException);
    }

    // Some more code...
}

static class Program
{	
	internal const string C_ExecutingApplicationName = "My Application Name";

	// private members
	private static Form mainForm;

	[STAThread]
	static void Main()
	{
		Application.EnableVisualStyles();
		Application.SetCompatibleTextRenderingDefault(false);
		AppDomain.CurrentDomain.SetPrincipalPolicy(System.Security.Principal.PrincipalPolicy.WindowsPrincipal);

		// Set up a catch all error handler in case we have an error in code where we don't have a specific handler
		ExceptionManager exceptionManager = ExceptionManager();

		// Set up a catch all error handler in case we have an error in code where we don't have a specific handler
		ExceptionManager exceptionManager = new ExceptionManager();
		// Configure Exception manager, i.e., 
		// exceptionManager.NotificationType = Inform;
		// or 
		// exceptionManager.NotificationType = ApplicationEventLog;
		// or 
		// exceptionManager.NotificationType = DatabaseLog;
		// or 
		// exceptionManager.NotificationType = All;
		// etc. with supporting code with the ExceptionManager class

		// Run it...
		mainForm = new Forms.Main();
		Application.Run(mainForm);
	}
}

ragupathi.p wrote:

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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

e.Graphics.DrawRectangle(Pens.Black, rect);
e.Graphics.DrawString("Printing from Windows form",new Font("Arial",10,FontStyle.Bold ), Brushes.Black, recf);