I’ve been having some issues with WF rules files over the last few weeks. I am using code generation to build some services that use workflow’s in the business layer. The problems start when I run a code generation after editing the workflow rules and want to compare the difference. The result tends to be something like this for what is actually the same content:
This is even a tame example. I have had full color difference indicators before.
Someone at work was kind enough to figure out the correct command line switches to use in order to replace the standard TFS compare/merge tool with WinMerge. I originally blamed Pants for the info, but he then accused Eddie. Here are the goods:
In Visual Studio do the following:
As I have been writing some SQL Server based software recently, I want to expose a standard way of providing searching capabilities for tables and views. The initial implementation started with a set of WHERE conditions like the following:
WHERE (FieldA = @FieldAValue OR @FieldAValue IS NULL)
(FieldB = @FieldBValue OR @FieldBValue IS NULL)
I now want to extend this functionality to include sorting and perhaps paging as well. I came across this article by Erland Sommarskog (SQL Server MVP) which address a ton of sorting variations.
This post has some good tips for increasing the performance of the VS2005 IDE.
I encountered a bit of a curly one today with my workflows.
Generally, I am executing WF workflows synchronously because I am using them as my business layer implementation for distributed services. This means that in order to return a value from a service call, the workflow needs to complete first. Because WF executes asynchronously by default, I am using the ManualWorkflowSchedulerService to execute workflows on the same thread as the calling process.
This became a problem when I actually want a combination of synchronous and asynchronous workflow executions for a service call. With the DefaultWorkflowSchedulerService and ManualWorkflowSchedulerService in WF, this wouldn’t be supported in the one workflow runtime instance.
My first solution was to host two runtimes, one using the ManualWorkflowSchedulerService for executing workflows synchronously, and one using the DefaultWorkflowSchedulerService for executing the asynchronous workflows. The hitch is that I also need impersonation, but this doesn’t appear to be possible when executing workflows using the DefaultWorkflowSchedulerService as the impersonated credentials get lost.
For some bizarre reason (meaning I really don’t know why), I have always built cache key values as strings when the key being represented is a set of values. On Friday, my eyes were opened to the fact that it is much better to create a rich object that represents the key values. The question then come down to equality testing of the reference type to make sure that the cache keys are correctly identified. Understanding Equality in C# on CodeProject is a concise article that was helpful for getting this right.
I have written some custom activities for WF, but have recently found a bit of a problem with my implementation. I have wanted to persist information against the workflow instance that contains my custom activity (or many instances of the custom activity). I thought I was being very clever by resolving the owning workflow and then storing my information against the workflows UserData IDictionary property.
Even the description of the UserData property sounded appropriate according to my good intentions.
Gets an IDictionary that associates custom data with this class instance.
The problem that came up was that the data put into this property was persisted between multiple calls to execute the workflow type in the workflow runtime across any user that called it. I have had to change my implementation to store the data elsewhere to avoid this issue.
Ever come across a WorkflowValidationFailedException at runtime even though the project containing the workflow was successfully validated and compiled without any errors? The reason for this occurring is how the compiler manages references.
Lets look at a simple solution that contains ProjectA, ProjectB and ProjectC. ProjectA references ProjectB which then references ProjectC.
ProjectA contains a form that references ClassB in ProjectB like this:
Paul Stovell has posted some great points about the usage of code generation. This is of great interest to me because I am using code generation to produce a base service implementation as I develop an SOA application. I have a couple of thoughts to add to his list:
7. Code generation is not a license to avoid unit testing.
There is a tendency to not test generated code because the original unit testing of the templates was successful. Once you have generated code, it should now be considered alive in that it will be run in an environment, interact with other systems and will be required to work with data that didn’t exist in the code generation templates or their original test scenarios. Anything could cause problems because specific circumstances weren’t considered as the template was developed.
8. Code generation does not produce a product.
This point aligns with Paul’s 5th and 6th points. Code generation being a tool, shouldn’t produce a product. Use code generation to output common base level code that can then be customized and built upon. Code generation output can be the basis of a product, but shouldn’t be the entire product. If you have done this, then either you have wasted too much time on your templates, or your product design needs some serious CPR.
On a side note, the code generator I decided to use SmartCode because it is the easiest to use and understand in the freeware market. It is also open source so I can deal with any issues or restrictions that I come across. I have since also started to contribute my changes to the project.
I want to change some values in my application config file at build time depending on the build type (Debug or Release for example). Web deployment projects added this functionality, but it is tightly coupled to that project type. I want to use this functionality in any .Net project type.
Is there a way to do this?