We Keep Coding

Implementing a refactoring system for my autogenerated code

I have a little visual system for generation FSM's where the user can draw a graph using boxes (states) and link them with lines (transitions). This, in the end, generates c# code when user presses the "Generate code" button that defines the FSM in runtime.
I want my users to be able to change things like graph name, transitions names, states names, delete nodes, delete transitions and a bit more after the first save, so, I need a way to handle refactoring.
I'm struggling trying to find a non intrusive way to accomplish this. Have tried to apply a modification of a do/redo algorithm I made some time ago but couldn't be able to get something nice.
Could anyone explain how to create such a system, making it as less intrussive with existent code as possible?
Cheers.

I would suggest keeping the state in your graph datastructure, and generating the C# code anew on changes to the FSM, this is a simple solution that will allow arbitrary modification of the FSM-datastructure without having to worry about applying said modifications to the generated code.
For implementing 'refactorings' of the base FSM-data structure, you could use something like a Command Pattern to encapsulate the refactorings and undo/redo operations.

Issues with Orchard CMS

I have researched for some time the Orchard CMS and I'm pleased with some of his futures but also I have some issues that I don't know how to deal with them:
All the items (content type) are linear and they don't support a tree like data structure
(Ex: books > titles > web-links)
One of the big problem (depending how you see things) is that the model and the view for the items are coupled (content part > driver with display / editor views)
So for a new page the model, view and position are locked and you can have only one view of the model.
Use of advance language futures the are not suited for beginner developers and are not very clear (dynamic functions, clay objects - nice future, ...)
// Creating table VPlayerRecord
SchemaBuilder.CreateTable("VPlayerRecord", table => table
.ContentPartRecord()
.Column("Title", DbType.String)
.Column("VideoUrl", DbType.String)
.Column("WidthPx", DbType.Double)
.Column("HeightPx", DbType.Double)
);
This syntax is not very clear for beginner developers and is a bit over engineered. Also because the model is a dynamic object in the view we don't have any intellisense support.
To build a new page we have something like three degree of separation (3 projects)
Build a content part module
Build a content type
Build a theme module
How do you overcome these issues in your projects with Orchard CMS? and what other issues have you found and fixes :)

read this: http://orchardproject.net/docs/Creating-1-n-and-n-n-relations.ashx and this: http://orchardproject.net/docs/Creating-lists.ashx
How is this a problem and why do you see this as coupling? What alternative do you see?
Where do you see this as a problem and how has it blocked you?
edit on 2: it is not true that you can have only one view of the model. You can have any number of display types. For example, the summary view of items is handled this way. You also have display types for admin views, and you can add your own.
Not sure what you mean by "position is locked". If we mean the same thing by position, I'm puzzled by how you could have gotten such an idea. Relative positioning of parts and fields can be changed through placement.info.
edit on 3: even with this example, I'm not sure what would be difficult here. This is fairly expressive imo. Were you confused yourself or are you just assuming people would be?
You are claiming that this is over-engineered. How would you simplify it then? What feature do you think is not needed?
You don't get IntelliSense in views on model objects but the flexibility you gain by doing so justifies it by a very large margin. Ask anyone who's been making real use of it.
new 4th point: I can't see a reason why you would separate that into three modules or why you think you should. I've certainly never seen an example of that. I would also point out that creating a part and a type are often done by two different people (a type creator is often just a consumer of existing parts). But again you don't have to separate them into different modules.
A theme is clearly a different concern from the two others and makes sense to be a separate project but a theme can come with code and can actually in principle do everything a module is doing. So if you want to package a part, type and theme into a single package, you could do that. It wouldn't make a lot of sense but you could.
Finally, I don't see how any of those four points are related to page creation.

Orchard has to be taken as a challenge. As a beginner I have quickly built a few sites with ease. After that the learning curve became steeper. I've read many articles on the subject, numerous times.
I have used some CMS's before and had some knowledge what is the nature of managing content. Learning Orchard opened a whole new definition of content management. Now I can think of solving some everyday tasks and various business processes by implementing Orchard.
The whole thing is built in a very abstract layer, forcing you to think abstract too. If you follow this way, there are many blog posts, as well as official documentation to help you.
There are few basic building blocks and concepts that can be used like a bricks. Sounds like a phrase, I've heard it hunderts of times. I have also seen thousands of houses built from red square bricks, and they were all different, while the bricks were all equal. Such things can be accomplished with Orchard.
Read and understand the programming patterns. They are essential part of knowledge that will help you in solving Orchard based tasks. They will also help you change the way you are accomplishing your non Orchard related tasks.
I would say, there are two basic areas one need to understand. Storing and retreiving the piece of content is one, while presenting it to the crowd is the other. It might look difficult, it is difficult, but the goodies behind are delightfull. Not to mention great guys, some from evil empire, some not, that will certainly help you along the way. Not to forget, git's are your best friend. There are many wheels already invented. Caution, neither comes with free lunch.
P.S. I haven't write such a long post since usenet times. It might not be suitable for a site like this. It's kind a way to give a thanks to this French guy, and to all other Orchard evangelists from Poland, over Cyprus to the States. They saved my ass in many occasions.

Undo Redo in WPF/C# in an already functional application

I have done some research already as to how I can achieve the title of this question. The app I am working on has been under development for a couple of years or so (slow progress though, you all know how it is in the real world). It is now a requirement for me to put in Undo/Redo multiple level functionality. It's a bit late to say "you should have thought about this before you started" ... well, we did think about it - and we did nothing about it and now here it is. From searching around SO (and external links) I can see that the two most common methods appear to be ...
Command Pattern
Memento Pattern
The command pattern looks like it would be a hell of a lot of work, I can only imagine it throwing up thousands of bugs in the process too so I don't really fancy that one.
The Memento pattern is actually a lot like what I had in my head for this. I was thinking if there was some way to quickly take a snapshot of the object model currently in memory, then I would be able to store it somewhere (maybe also in memory, maybe in a file). It seems like a great idea, the only problem I can see for this, is how it will integrate with what we have already written. You see the app as we have it draws images in a big panel (potentially hundreds) and then allows the user to manipulate them either via the UI or via a custom built properties grid. The entire app is linked up with a big observer pattern. The second anything changes, events are fired and everything that needs to update does. This is nice but I cant help thinking that if a user is entering text into a texfield on the properties grid there will be a bit of delay before the UI catches up (seems as everytime the user presses a key, a new snapshot will be added to the undo list). So my question to you is ....
Do you know of any good alternatives to the Memento pattern that might work.
Do you think the Memento pattern will fit in here or will it slow the app down too much.
If the Memento pattern is the way to go, what is the most efficient way to make a snapshot of the object model (i was thinking serialising it or something)
Should the snapshots be stored in memory or is it possible to put them into files?
If you have got this far, thankyou kindly for reading. Any input you have will be valuable and very much appreciated.

Well , Here is my thought on this problem.
1- You need multi level undo/redo functionality. so you need to store user actions performed which can be stored in a stack.
2- Your second problem how to identify what has been changed by a operation i think through Memento pattern , it is quite a challenge. Memento is all about toring initial object state in your memory.
either , you need to store what is changed by a operation so that you can use this information to undo the opertions.
Command pattern is designed for the Undo/Redo functionality and i would say that its late but its worth while to implement the design which is being used for several years and works for most of the applications.

If performance allows it you could serialize your domain before each action. A few hundred objects is not much if the objects aren't big themselves.
Since your object graph is probably non trivial (i.e. uses inheritance, cycles,...) the integrated XmlSerializer and JsonSerializers are out of question. Json.net supports these, but does some lossy conversions on some types (local DateTimes, numbers,...) so it's bad too.
I think the protobuf serializers need either some form of DTD(.proto file) or decoration of all properties with attributes mapping their name to a number, so it might not be optimal.
BinaryFormatter can serialize most stuff, you just need to decorate all classes with the [Serializable] attribute. But I haven't used it myself, so there might be pitfalls I'm not aware of. Perhaps related to Singletons or events.

The critical things for undo/redo are
knowing what state you need to save and restore
knowing when you need to save the state
Adding undo/redo after the fact is always a painful thing to do - (I know this comment is of no use to you now, but it's always best to design support into the application framework before you start, as it helps people use undo-friendly patterns throughout development).
Possibly the simplest approach will be a memento-based one:
Locate all the data that makes up your "document". Can you unify this data in some way so that it forms a coherent whole? Usually if you can serialise your document structure to a file, the logic you need is in the serialisation system, so that gives you a way in. The down side to using this directly is usually that you will usually have to serialise everything so your undo will be huge and slow. If possible, refactor code so that (a) there is a common serialisation interface used throughout the application (so any and every part of your data can be saved/restored using a generic call), and (b) every sub-system is encapsulated so that modifications to the data have to go through a common interface (rather than lots of people modifying member variables directly, they should all call an API provided by the object to request that it makes changes to itself) and (c) every sub-portion of the data keeps a "version number". Every time an alteration is made (through the interface in (b)) it should increment that version number. This approach means you can now scan your entire document and use the version numbers to find just the parts of it that have changed since you last looked, and then serialise the minimal amount to save and restore the changed state.
Provide a mechanism whereby a single undo step can be recorded. This means allowing multple systems to make changes to the data structure, and then when everything has been updated, triggering an undo recording. Working out when to do this may be tricky, but it can usually be accomplished by scanning your document for changes (see above) in your message loop, when your UI has finished processing each input event.
Beyond that, I'd advise going for a command based approach, because there are many benefits to it besides undo/redo.

You may find the Monitored Undo Framework to be useful. http://muf.codeplex.com/
It uses something similar to the memento pattern, by monitoring for changes as they happen and allows you to put delegates on the undo stack that will reverse / redo the change.
I considered an approach that would serialize / deserialize the document but was concerned about the overhead. Instead, I monitor for changes in the model (or view model) on a property by property bases. Then, as needed, I use the MUF library to "batch" related changes so that they undo / redo as a unit of change.
The fact that you have your UI setup to react to changes in the underlying model is good. It sounds like you could inject the undo / redo logic there and the changes would bubble up to the UI.
I don't think that you'd see much lag or performance degradation. I have a similar application, with a diagram that we render based on the data in the model. We've had good results with this so far.
You can find more info and documentation on the codeplex site at http://muf.codeplex.com/. The library is also available via NuGet, with support for .NET 3.5, 4.0, SL4 and WP7.

WPF dynamic data architecture

So I'm having some level of difficulty with architecting a particular solution with some dynamic data elements....
So I've got two places where I'm storing data -- a database and a pdf (although I only write to the pdf - I never read from it). You can think of the pdf working a lot like a database -- except that the schemas for the table and the pdf are different. Different fields will go into the database and the pdf. Users will be able to edit certain fields -- but not all fields. I'm trying hard to enforce a separation of UI and logic here, but I'm running into difficulties. My logic is essentially having to tell my UI what UI elements to create and what restrictions to enforce on them (required, options, etc) so I feel a bit like I'm making a UI from within my business logic; but I don't really know how else to do this with dynamic data elements. When this is done, I have to write to the database and then print the pdf.
You can essentially think of this question as... "I have a ton of disparate data. I need to do different things with different pieces of data. I can't figure out a way to do this generically without making some coding atrocity." Does anyone have any ideas?

What you're doing is developing an application framework, not an application. You might benefit from looking at other application frameworks (there are a billion of them) to see how others have approached the problem.
I can tell you right now that your project will be successful in direct proportion to how well you've designed the scheme for handling metainformation. Steve McConnell's general rule that data is easier to debug than code is pretty much the guiding beacon for this kind of project.
WPF is really, really well suited for this kind of thing. I've been porting over my own app framework from Windows Forms to WPF and am kind of amazed at how much code I don't have to write.

If I were you, I would look at all the information about fields users need to view/edit, and see what common themes I can see. Looking at your question I would probably create a class/structure that contains the following:
struct FieldInfo
{
string FieldName;
string DisplayName;
string DataType;
bool Required;
delegate Validator;
string OldValue;
}
delegate bool Validator(string input, out string message);
I would return FieldInfo[] from the Business Logic, then in the UI use that array to determine what to show the user. This way, even the validation login is the your business logis (using the delegate) and the UI only has to decide what elements to display for each type. You could even go a step farther and have the FieldInfo struct have an element name telling the UI what element to use for that field (Textbox, DDL, etc)

Keeping your main form class short best practice

I have a main form at present it has a tab control and 3 data grids (DevExpress xtragrid's). Along with the normal buttons combo boxes... I would say 2/3 rds of the methods in the main form are related to customizing the grids or their relevant event handlers to handle data input. This is making the main forms code become larger and larger.
What is an ok sort of code length for a main form?
How should I move around the code if necesary? I am currently thinking about creating a user control for each grid and dumping it's methods in there.

I build a fair number of apps at my shop and try to avoid, as a general rule, to clog up main forms with a bunch of control-specific code. Rather, I'll encapsulate behaviors and state setup into some commonly reusable user controls and stick that stuff in the user controls' files instead.
I don't have a magic number I shoot for in the main form, instead I'll use the 'Why would I put this here?' test. If I can't come up with a good reason as to why I'm thinking of putting the code in the main form, I'll avoid it. Otherwise, as you've mentioned, the main form starts growing and it becomes a real pain to manage everything.
I like to put my glue code (event handler stuff, etc.) separate from the main form itself.
At a minimum, I'll utilize some regions to separate the code out into logically grouped chunks. Granted, many folks hate the #region/#endregion constructs, but I've got the keystrokes pretty much all memorized so it isn't an issue for me. I like to use them simply because it organizes things nicely and collapses down well in VS.
In a nutshell, I don't put anything in the main form unless I convince myself it belongs there. There are a bunch of good patterns out there that, when employed, help to avoid the big heaping pile that otherwise tends to develop. I looked back at one file I had early on in my career and the darn thing was 10K lines long... absolutely ridiculous!
Anyway, that is my two cents.
Have a good one!

As with any class, having more than about 150 lines is a sign that something has gone horribly wrong. The same OO principles apply to classes relating to UI as everywhere else in your application.
The class should have a single responsibility.

A number is hard to come up with. In general, I agree with the previous two posters, it's all about responsibilities.
Ask yourself, what does the code to customize behavior for grid 1 have to do with grid 2?
What is the responsibility of the main form? Recently I have been subscribing to MVP design patterns (MVC is fine as well). In this pattern, you main form is the presenter, or ui layer. It's responsibility should be to present data and accept user input.
Without seeing your code, I can only guesstimate as to what is the best course of action. But I agree with your feelings that each grid and it's customization code should live in a different control. Perhaps the responsibility of the main form should be to merely pass the data to the correct control and pass requests from the control back to the controller/presenter. It is the responsibility of each control to understand the data passed to it, and display it accordingly.
Attached is an example MVP implementation.
http://www.c-sharpcorner.com/UploadFile/rmcochran/PassiveView01262008091652AM/PassiveView.aspx