Adding Scripting Functionality to .Net Applications

Adding scripting functionality to .NET applications

Oleg Shilo's C# Script solution (at The Code Project) really is a great introduction to providing script abilities in your application.

A different approach would be to consider a language that is specifically built for scripting, such as IronRuby, IronPython, or Lua.

IronPython and IronRuby are both available today.

For a guide to embedding IronPython read
How to embed IronPython script support in your existing app in 10 easy steps.

Lua is a scripting language commonly used in games. There is a Lua compiler for .NET, available from CodePlex -- http://www.codeplex.com/Nua

That codebase is a great read if you want to learn about building a compiler in .NET.

A different angle altogether is to try PowerShell. There are numerous examples of embedding PowerShell into an application -- here's a thorough project on the topic:
Powershell Tunnel

Using C# as a scripting language for a C# application

Specifically for auto-complete, you will need to make use of two systems: a parser, and reflection.

A parser is a pretty straightforward concept, in theory, but I'm sure that it won't be easy to write for a language with as much syntactic sugar and as many context-sensitive keywords as C#.

Since .NET is inherently reflective, and provides a reflection framework, that part shouldn't be incredibly painful, either. Reflection allows you to manipulate the object-oriented elements comprising compiled assemblies--and the assemblies themselves--as objects. A method would be a Method object, for example. You can take a peek at this system by examining the members of the Type class, which provide one basic starting point for reflection. Another useful starting point is Assembly. MSDN, as usual, has a wealth of "official" information in a structured format.

How do I get started designing and implementing a script interface for my .NET application?

[EDIT: As covered at length in the comments in this, assuming you have a significant need to enable internal scripting where you are hosting snippets or functions someone gives you to customise your app, as opposed to a purely external scenario where one is providing a facaade to allow people to dig stuff out of your app on a more rigid predefined basis]

IronRuby and IronPython are very neat and appropriate for this (but as the other answer says, PowerShell may be appropriate if you have a more infrastructure-type thing).

EDIT: Other ideas for enabling internal scripting are

• using Windows Workflow Foundation (exposing activities to it and/or hosting instances of workflows)
• using Spring.NET's Expression Language (which is terse, easy to doc and learn but surprisingly powerful)

EDIT 2 June 2011: IronJS may also be a suitable candidate, there's a Hanselminutes that talks it thru.

Extending C# .NET application - build a custom scripting language or not?

I've heard very good things about IronPython for exactly this type of scenario. I'd certainly risk spending a few hours on a quick proof-of-concept, to see how it pans out.

Michael Foord will happily wax lyrical about the success of IronPython in similar cases (most specifically for him, for spreadsheet savvy users), and his book covers (IIRC) a few pointers about hosting it from .NET.

Adding & Executing small .net scripts in WPF app

Yes it is possible. However, It is not trivial unless you relax the requirements.

Here are several ways in which to accomplish something like this:

Option 1:

You can approach this problem by creating (or finding an existing) pseudo-language based on tokens to describe the actions you need performed.

SharePoint does something similar, as do some frameworks that allow dynamic code to be generated from config files.

Basically, you use XML or any pseudo-language of choice to define the behaviors, parameters, and conditions for your methods. You can even include actual C# code in there if you wish.

You can then generate dynamic assembly on the fly and using reflection invoke the method on your toolbar.

Look at these namespaces for more info:

System.CodeDom.Compiler 
System.Reflection.Emit

The System.Reflection.Emit namespace has an ILGenerator class which you can use to create IL instructions as part of dynamically generated types.

This is probably more involved than it's worth for this small task.

Option 2:

Another approach is to use a plug-in architecture and dynamically load DLL's with your specific toolbar/component related methods (based on some interface so you can execute what you need easily without lots of hard coding, like a Command pattern, and depending on the configuration you load the appropriate assembly and execute it's logic to configure your component.

This is still probably more involved than you want to deal with for the task at hand.

Option 3:

Probably the easiest to implement and I think makes the most sense for a small project.

You can include all of the methods you need in a common assembly and have it referenced all the time. Then use configurations to determine which methods need to be called or executed depending on which components you are loading at run-time. This circumvents the need for complex over-engineering and accomplishes the same task.

The downside of Option 3 is that you must recompile your project any time a new component is added or configured. Since you are not REALLY trying to create a dynamic, extensible application, and just looking to handle some configuration of UI components, this option still makes sense because if you were to define new components that can be configured (a new menu or an additional widget), it stands to reason you'd be recompiling your project at that time anyway.

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