Date: 10/05/07 (C Sharp)    Keywords: no keywords

Hey guys. I know I've seen this before, but I can't, for the life of me, remember how to do it or where I saw it . . .

I need to tell a constructor to fail. Basically, I'm wrapping some unmanaged calls to a system DLL. I need to tell the class constructor to gracefully catch the exception and return null if there was an error in the constructor. Anyone know / remember how to do this?

public class ServiceInternalInstaller {
	[DllImport( "advapi32.dll" )]
	public static extern IntPtr OpenSCManager( string lpMachineName, string lpSCDB, int scParameter );

	private IntPtr m_pSCM = IntPtr.Zero;

	public ServiceInternalInstaller() {
		const int SC_MANAGER_CREATE_SERVICE = 0x00000002;
			try {
			m_pSCM = OpenSCManager( null, null, SC_MANAGER_CREATE_SERVICE );
			if( m_pSCM == 0 ) {
				throw new Exception( GetLastErrorMessage() );
			}
		} catch( Exception e ) {
			Console.Error.WriteLine( e.Message );
		}
	}
}

...

ServiceInternalInstaller oInstall = new ServiceInternalInstaller();
if( oInstall == null ) return;

Source: http://community.livejournal.com/csharp/86684.html