Exception handling in transactionscope

Question

This method is called in my business service from an asp.net mvc controller. Should there occur an exception or not I need to return a Result object.

The result class is experimental, maybe there is something better.

How would you do the exception handling, if I do not expect a special exception.

I just want to show the user the error message from the exception in my javascript file

with a messagebox if the success returns false.

 public Result CreateTestplan(Testplan testplan)
 {
    using (var con = new SqlConnection(_connectionString))
    using (var trans = new TransactionScope())
    {
       con.Open();

       _testplanDataProvider.AddTestplan(testplan);
       _testplanDataProvider.CreateTeststepsForTestplan(testplan.Id, testplan.TemplateId);
       trans.Complete();
   }
  }

class Result
{
   public bool Success {get;set;}
   public string Error {get;set;}
}

Chris · Accepted Answer · 2012-07-01T21:07:21.683

2

Wrap the entire transaction in a Try/Catch block & catch Exceptions. Within the catch block set the Error text on your Result to the exception text. Here's how it looks in code:

 public Result CreateTestplan(Testplan testplan)
 {
    Result res = new Result();
    try
    {
    using (var con = new SqlConnection(_connectionString))
    using (var trans = new TransactionScope())
    {
       con.Open();

       _testplanDataProvider.AddTestplan(testplan);
       _testplanDataProvider.CreateTeststepsForTestplan(testplan.Id, testplan.TemplateId);
       trans.Complete();
       res.Success = true;
       res.Error = string.Empty;
   }
   }
   catch (Exception e)
   {
       res.Success = false;
       res.Error = e.Message;
   }
   return result;
  }

class Result
{
   public bool Success {get;set;}
   public string Error {get;set;}
}

Of course, your service will end up swallowing any exceptions, so you need to make sure that the transaction failing doesn't leave your program in an inconsistent state.

edited Jul 01 '12 at 21:07

answered Jul 01 '12 at 20:55

Chris

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what inconsistent state could there be? Normally if a transaction fails everything is rolled back. – Pascal Jul 01 '12 at 20:59
@Steve yes... still wanted to give him a 5min chance to correct ;-) – Pascal Jul 01 '12 at 21:02
Now it works, still I find the exploitation of the default values (bool is false by default) not a good habit. I will prefer an explicit setting of the property `Success = false` and the `Error = String.Empty`. Hey, what's that `request` var now? – Steve Jul 01 '12 at 21:07
That's entirely fair, I'll include those edits. As for the transaction question Pascal, I was referring to any in-code objects you may have. Imagine that upon calling AddTestPlan you increment a counter (not sure why you'd do it at the start), but then the transaction fails. The counter is now incorrectly recording the number of TestPlans added. If it's just a pure SQL transaction you have nothing to worry about. – Chris Jul 01 '12 at 21:10
@Chris Did not understand all about that counter stuff, but yes its just sql transaction, what else could there be? Distributed transaction over multiple servers you speak of that? – Pascal Jul 01 '12 at 21:13
@Pascal Exactly, but if you're not using those, nothing to worry about:) – Chris Jul 01 '12 at 21:14

Exception handling in transactionscope

1 Answers1