Intercepting an exception inside IDisposable.Dispose

Question

In the IDisposable.Dispose method is there a way to figure out if an exception is being thrown?

using (MyWrapper wrapper = new MyWrapper())
{
           


        

Answer 1

It is not possible to capture the Exception in the Dispose() method.

However, it is possible to check Marshal.GetExceptionCode() in the Dispose to detect if an Exception did occur, but I wouldn't rely on that.

If you don't need a class and want just want to capture the Exception, you can create a function that accepts a lambda that is executed within a try/catch block, something like this:

HandleException(() => {
    throw new Exception("Bad error.");
});

public static void HandleException(Action code)
{
    try
    {
        if (code != null)
            code.Invoke();
    }
    catch
    {
        Console.WriteLine("Error handling");
        throw;
    }
}

As example, You can use a method that automatically does a Commit() or Rollback() of a transaction and do some logging. At this way you don't always need a try/catch block.

public static int? GetFerrariId()
{
    using (var connection = new SqlConnection("..."))
    {
        connection.Open();
        using (var transaction = connection.BeginTransaction())
        {
            return HandleTranaction(transaction, () =>
            {
                using (var command = connection.CreateCommand())
                {
                    command.Transaction = transaction;
                    command.CommandText = "SELECT CarID FROM Cars WHERE Brand = 'Ferrari'";
                    return (int?)command.ExecuteScalar();
                }
            });
        }
    }
}

public static T HandleTranaction(IDbTransaction transaction, Func code)
{
    try
    {
        var result = code != null ? code.Invoke() : default(T);
        transaction.Commit();
        return result;
    }
    catch
    {
        transaction.Rollback();
        throw;
    }
}