C# – Why win32 exception are not caught by c# exception handling mechanism

cexception handlingwinforms

I have a winforms application.Winforms start with Program.cs where we have main() defined.I have put this code in try-catch block.

 [STAThread]
    static void Main()
    {
        try
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new frmSplash());
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
            if (ex.InnerException != null)
            {
                MessageBox.Show(ex.InnerException.ToString());
            }
        }
    }

Whenever there is a win32 exception,this mechanism fails and unhandled exception message is thrown and application crashes.
I have 2 questions regarding this code:

1) Why win32 exceptions are not caught.

2) Is it a good practice to catch exceptions at the highest level.

Best Answer

EDIT : as Pratik pointed out, the following answer applies to .NET 1.0 and .NET 1.1 only. Starting with .NET 2.0, non-CLS exception should be caught as a RuntimeWrappedException.

Because Win32 exceptions do not derive from the .NET Exception class. Try :

try {
} catch (Exception ex) {
    // .NET exception
} catch {
    // native exception
}

See Catch non-CLSCompliant exceptions in general handlers for more information.

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