Can we throw exception in one method and handle it in different method?

Question

I have two methods in which method 1 throw's an exception. Method 2 calls method 1 and if it throws exception it should be handled in method 2.

Here is my method 1

 private Customer GetCustomer(string unformatedTaxId)
        {
            if (loan.GetCustomerByTaxId(new TaxId(unformatedTaxId)) == null)
            {
                throw new NotFoundException("Could not find the customer corresponding to the taxId '{0}' Applicant address will not be imported.", new TaxId(unformatedTaxId));

            }

            return loan.GetCustomerByTaxId(new TaxId(unformatedTaxId));
         }

Now in the following method i am calling method 1

public void ProcessApplicantAddress(ApplicantAddress line)
        {
            try
            {
                Customer customer = GetCustomer(line.TaxId);


                Address address = new Address();
                address.AddressLine1 = line.StreetAddress;
                address.City = line.City;
                address.State = State.TryFindById<State>(line.State);
                address.Zip = ZipPlusFour(line.Zip, line.ZipCodePlusFour);
              }
              catch(NotFoundException e)
            {
                    eventListener.HandleEvent(Severity.Informational, line.GetType().Name, e.Message);
            }

My problem is i am getting an unhandled exception, but i should catch it in the method 2. Please help me from this.

My NotFoundException Class

//  class NotFoundException


  public class NotFoundException : Exception
    {



    public NotFoundException() : base() 
    { 
    }


    public NotFoundException(string message): base(message) 
    { 
    }


    public NotFoundException(string format, params object[] args): base(string.Format(format, args)) 
    { 
    }

    public NotFoundException(string message, Exception innerException) : base(message, innerException) 
    { 
    }


    public NotFoundException(string format, Exception innerException, params object[] args) : base(string.Format(format, args), innerException)
    { 
    }
}

This should work. What is the detail of the unhandled exception? Maybe it's not the exception you think it is. — John Saunders, Sep 05 '13 at 16:43
Your NotFoundException has a (string, TaxID) constructor? Why that over just a string? — User, Sep 05 '13 at 16:46
As a debugging tip: press Ctlr + Alt + E, which brings up the Exceptions dialog. Select `Thrown` for `Common Language Runtime Exceptions`. — gunr2171, Sep 05 '13 at 16:54
can you please post the code for the class NotFoundException specially the constructor method — Mauricio Gracia Gutierrez, Sep 05 '13 at 17:12
When the indenting is messed up like this, we almost always look at a code snippet that doesn't match the real code. And cannot show the cause of the problem. — Hans Passant, Sep 05 '13 at 17:17

score 0 · Answer 1 · answered Sep 05 '13 at 17:17

Try-Catch blocks are relatively expensive operations, and they can make debugging difficult. I highly recommend you avoid using an error handling pattern with try-catch. Instead, you could just skip the method that throws and check for null:

public void ProcessApplicantAddress(ApplicantAddress line)
{

    var customer = loan.GetCustomerByTaxId(new TaxId(line.TaxId));

    if (customer == null)
    {
        eventListener.HandleEvent(Severity.Informational, "ApplicantAddress", String.Format(""Could not find the customer corresponding to the taxId '{0}' Applicant address will not be imported."", line.TaxId));
    }
    else
    {
        var address = new Address();
        address.AddressLine1 = line.StreetAddress;
        address.City = line.City;
        address.State = State.TryFindById<State>(line.State);
        address.Zip = ZipPlusFour(line.Zip, line.ZipCodePlusFour);
        //do whatever else you need to do with address here.
    }
}

Your originally posted code should work, but I am guessing that GetCustomerByTaxId is throwing an exception of its own when the customer isn't found. You might consider stepping through that method and making sure it is actually going to return null when no customer is found.

Yea this is my previous version and it is working fine. But my manager told me to get rid of that and throw an exception in GetCustomer() method and handle it in ProcessApplicantAddress() method using try catch blocks. Any clue to solve this issue? — user2619542, Sep 05 '13 at 17:23
To be honest, if you are being directed to do something a certain way, I'd ask your manager to explain in detail the pattern he's looking for, and why. The only other way you'll be able to get help from Stack Overflow is if you post the details of the Unhandled Exception. — User, Sep 05 '13 at 17:44
Like what kind of details? Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. — user2619542, Sep 05 '13 at 17:49

score 0 · Answer 2 · answered Sep 05 '13 at 17:18

0

Your throw is never triggered because the functions executed within if statement raised another exception, so the catch isn't trigger because it's another type of exception.

answered Sep 05 '13 at 17:18

Jeroen van Langen

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How can i fix this issue? Any clue – user2619542 Sep 05 '13 at 17:20
Ofcourse, but throwing an exception of returning null is much different. If the method throws any exception, do you want to throw a new one? Or only when the result for the `loan.GetCustomerByTaxId == null` – Jeroen van Langen Sep 05 '13 at 17:30
When my result is null. – user2619542 Sep 05 '13 at 17:31
Then your function is right this way. And the results are as aspected. – Jeroen van Langen Sep 05 '13 at 17:32
Sorry i didn't get you @Jeroen – user2619542 Sep 05 '13 at 17:34
The specs you gave are, when the `loan.GetCustomerByTaxId` returns `null` it should raise an NotFoundException. But the `loan.GetCustomerByTaxId` never returns any value, but that method raises an exception. And because you didn't caught that type of exception, your visual studio will say that there is one unhandled exception. So if you want to fix this, you should fix the `loan.GetCustomerByTaxId` method. – Jeroen van Langen Sep 05 '13 at 17:39
Can you provide me a solution for this issue please? – user2619542 Sep 05 '13 at 17:39
If the TaxId is correct then it will return a customer object for that particular taxId, otherwise it returns null then i should throw the exception. I am getting the TaxId field from the imported file – user2619542 Sep 05 '13 at 17:41
What type of exception is raised (the unhandled one) – Jeroen van Langen Sep 05 '13 at 17:43
Yep, Unhandled exception by user code, but i need to handle that in processapplicantaddress() method which i can't. :( – user2619542 Sep 05 '13 at 17:48
You could ask the teacher. I advise to read this: http://stackoverflow.com/questions/406385/handling-unhandled-exceptions-problem – Jeroen van Langen Sep 05 '13 at 17:50

Can we throw exception in one method and handle it in different method?

2 Answers2