You might want to use the generic Result<T> pattern shown here:
http://www.codeproject.com/useritems/alternative_2_out_keyword.asp On 7/12/06, Eddie Lascu <[EMAIL PROTECTED]> wrote:
Well, My sample method is a strip-down version of what I have in reality. My real method does more than just promoting the state (the application implements a parser). The method returns a boolean to signal whether everything went smoothly inside. Reference parameters, including a StringBuilder that constructs an error message in case something goes bad, are passed in. I had 'ref' in mind all along. For some reason, my fingers typed 'out' and since I recently switched to VS2005 I thought that this might be a new VS2005 behavior with regard to 'ref' parameters. Thanks everybody for waking me up!!! -----Original Message----- From: Discussion of advanced .NET topics. [mailto:[EMAIL PROTECTED] Behalf Of Mike Andrews Sent: Wednesday, July 12, 2006 11:54 AM To: ADVANCED-DOTNET@DISCUSS.DEVELOP.COM Subject: Re: [ADVANCED-DOTNET] Passing value parameters in VS2005 / .NET 2.0 Yes, as all the others have said, ref is the way to go. However, I'm wondering why you've not done something similar to this: static MyStateEnum ChangeToState1(MyStateEnum enState){ if ( enState == MyStateEnum.START_STATE){ enState = MyStateEnum.STATE1; } return enState; } just a thought. On 7/12/06, Eddie Lascu <[EMAIL PROTECTED]> wrote: > > Consider this: > > using System; > using System.Collections.Generic; > using System.Text; > > namespace TestOutParameterBehavior > { > public enum MyStateEnum > { > START_STATE = 0, > STATE1 = 1, > STATE2 = 2, > END_STATE > } > > class Program > { > static void Main(string[] args) > { > MyStateEnum enState = MyStateEnum.START_STATE; > > ChangeToState1(out enState); > > if (enState == MyStateEnum.START_STATE) > Console.WriteLine("The state didn't change!!!"); > else > Console.WriteLine("The state did change!!!"); > > Console.WriteLine("Press <Enter> to Exit..."); > Console.ReadLine(); > } > > static void ChangeToState1(out MyStateEnum enState) > { > if( enState == MyStateEnum.START_STATE ) > enState = MyStateEnum.STATE1; > } > } > } > > Why is it that I cannot test the value of my enumeration variable before I > assign to it? This small test app doesn't compile and the errors I am > getting are: > 1. Use of unassigned out parameter 'enState'; > 2. The out parameter 'enState' must be assigned to before control leaves > the > current method; > > Obviously, I need to use 'out' parameters, because enumerations are value > types and I need to preserve the changes done in the ChangeToState1 > method. > Am I missing something? Clearly this wasn't the case in VS2003 / .NET 1.1. > I > would understand the environment generating a warning in my case, but an > error? It's like I need to assign the out parameter no matter what. Well, > in > some cases (decided by the 'if' test) I don't want to do the assignment. > > Regards, > Eddie > > =================================== > This list is hosted by DevelopMentor(r) http://www.develop.com > > View archives and manage your subscription(s) at > http://discuss.develop.com > =================================== This list is hosted by DevelopMentor(r) http://www.develop.com View archives and manage your subscription(s) at http://discuss.develop.com =================================== This list is hosted by DevelopMentor(r) http://www.develop.com View archives and manage your subscription(s) at http://discuss.develop.com
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