Entries for Andrew Davey

Asynchronous Programming using LINQ Syntax [Asynchronous Programming using LINQ Syntax]

Andrew Davey — Wed, 16 Jan 2008 10:22:55 GMT

After reading http://blogs.msdn.com/wesdyer/archive/2008/01/11/the-marvels-of-monads.aspx
I created a program that enables creating multiple web requests asynchronously. Even the response streams are read using non-blocking IO!

var requests = new[]
{
    WebRequest.Create("http://www.google.com/"),
    WebRequest.Create("http://www.yahoo.com/"),
    WebRequest.Create("};

var pages =
    from request in requests select
// essentially we are defining the computation here
// it does NOT run here
        from response in request.GetResponseAsync()
        let stream = response.GetResponseStream()
        from html in stream.ReadToEndAsync()
        select new { html, response };

foreach (var page in pages)
{
    page(d => // do this when the page data is ready
    {
        Console.WriteLine(d.response.ResponseUri.ToString());
        Console.WriteLine(d.html.Substring(0, 40));
        Console.WriteLine();
    });
} // for loop kicks off the calls and does NOT block the main thread.

Console.ReadKey();

The code reads like it is synchronous, but it's really not! You get the benefit of easy to read and write code that is also uses non-blocking IO. So it's not using up threads waiting for each request to return.

Check out my blog post for the code that implements the Continuation Monad and provides the methods required to enable the LINQ syntax.
There is no explicit thread at all in my code. It uses the BeginXXX/EndXXX async methods.

I think it's amazing how LINQ can be leveraged to things other than querying data - All thanks to its monadic under-pinings.

in reply to Asynchronous Programming using LINQ Syntax

Boo now running on Java, coding in Eclipse [Boo now running on Java, coding in Eclipse]

Andrew Davey — Sat, 27 Oct 2007 13:22:23 GMT

Links:
http://blogs.codehaus.org/people/bamboo/archives/001623_introducing_boojay.html

http://blogs.codehaus.org/people/bamboo/archives/001629_boojay_does_eclipse.html

Good job Microsoft Dev Div people - You seemed to have ignored Boo enough to mean the developers of it are now heading in the JVM direction!

Whilst I'm all for Boo running on the JVM and .NET, what sucks is that I prefer .NET (BCL and runtime) way more than Java offerings.
The real kicker is that Eclipse integration for Boo means there is now a great IDE for it (sorry but SharpDevelop doesn't cut it).

Boo is a great language. If people want to start playing with it then they will probably go for the nicest experience i.e. Eclipse.
This means they'll be targeting Java. So we will have lost an amazing .NET language to Java!

Sad times. :(

For goodness sake get someone thinking about bringing Boo into the warm and fuzzy world of Visual Studio. PLEASE!

in reply to Boo now running on Java, coding in Eclipse

Mobile Model in MVP web app [Mobile Model in MVP web app]

Andrew Davey — Wed, 17 Oct 2007 18:33:33 GMT

This screencast continues from the work I demonstrated in a previous screencast: Script# to make writing a client-side web app much more seemless than the usual javascript/XML/JSON/web service madness.

I'm developing the ideas shown here in a project at the moment. If there is sufficient interest I may extract a framework to give to the community.

How do people feel about this approach to web development? What kinds of additions/modifications should be made?

p.s. I have a bit of a cold at the moment, so sorry for the croaky voice in the recording!

in reply to Mobile Model in MVP web app

Client-side Model-View-Presenter [Client-side Model-View-Presenter]

Andrew Davey — Fri, 28 Sep 2007 16:14:39 GMT

The model-view-presenter pattern is a very powerful way to manage user interaction. It seems popular to use it on the server-side when creating HTML, but why not use it client-side instead?
Our computers are powerful enough to run fairly complex JavaScript. Why burden the server with having to render the page contents?

In this screencast I use Script# to compile a C# project into JavaScript. This project contains the Model, View and Presenter logic.
The HTML page then uses the generated JavaScript.

There is a simple REST service on the server that returns data which is called by the Model. No HTML generation occurs on the server.

Download the source code. You must have Script# installed as well.

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Functional ADO.NET [Functional ADO.NET]

Andrew Davey — Sun, 02 Sep 2007 16:41:14 GMT

Whilst LINQ is almost here, there is still a place in the world for plain old ADO.NET programming. However, procedural ADO.NET code can often be cumbersome to write. Executing some SQL for a data reader can involve three nested layers of C# using statements.
In this screencast, I present a functional approach to using ADO.NET that wraps most of the boiler-plate code into a Database class.
It makes use of anonymous methods to allow the developer to provide the required code at different points in the ADO.NET code.
The result is a syntactically lightweight way to interact with a database.

The code used in the project can be downloaded here:
C# 3.0 http://www.aboutcode.net/screencasts/functional-ado.3.zip
C# 2.0 http://www.aboutcode.net/screencasts/functional-ado.2.zip (same as 3.0 but with non-inferred anonymous methods).

in reply to Functional ADO.NET

Tier Splitting C# Class Screencast [Tier Splitting C# Class Screencast]

Andrew Davey — Sat, 25 Aug 2007 16:32:52 GMT

I just uploaded a new screencast demonstrating my C# tier splitting tool.
Check it out here: http://www.aboutcode.net/2007/08/25/Tier+Splitting+C+Screencast.aspx

I don't mean this to be spam, I really want to get some feedback from developers and start a discussion around the topic.
Cheers!

in reply to Tier Splitting C# Class Screencast

.NET Developers in Bristol, UK [.NET Developers in Bristol, UK]

Andrew Davey — Wed, 08 Aug 2007 18:48:00 GMT

I recently moved to Bristol in the UK. I'm keen to know if there are any .NET developer meetings/user groups. Even if there are only a few people who want to meet up for a coffee and talk code for an hour, that would be excellent start!

in reply to .NET Developers in Bristol, UK

C# Syntactic Macros [C# Syntactic Macros]

Andrew Davey — Tue, 31 Jul 2007 12:06:33 GMT

After a late night hacking session, I finally have a working syntactic macro system for C#! It is comprised of a VS custom tool that uses the CSparser. The end result allows me to do this:

using System;
[Macro(AutoClass)]
public interface IModel
{
string FirstName { get; set; }
string Surname { get; set; }
int ID { get; }
event EventHandler FirstNameChanged;
event EventHandler SurnameChanged;
}

The CustomTool property of the IModel.cs file is set to "MacroExpander" and the Build action is set to None. This then generates a new file "under" the source file, called for example "IModel.generated.cs". This generated file contains the original interface (minus the bogus attribute) and a new class called "Model" that provides a stanard implementation of IModel. It includes private fields, a constructor, properties, events and event raising methods. The class is partial so you can still create a file called "Model.cs" alongside the interface and implement any methods. In addition, if you enter implementations of the interface properties/events in Model.cs then the generated class will not contain them. So it is easy to generate the 80% of standard members and custom write the others as required.

The sharp-minded out there will note that "AutoClass" is a parameter passed to the Macro attribute. The expansion process is able to load any IMacro implementation I care to write. The macro implementation is handed the parsed source tree and allowed to modify it as required. After all macros have expanded, the source tree is converted back to CS source text and outputted from the VS custom tool. This generated file is compiled by VS as usual.

I'm going to start using this AutoClass macro to generate most of my Model code (in the Model-View-Presenter architecture). Anywhere else I need code generation at this level I can create more macros easily.

If people are interested in seeing this product released in some way please get in contact. I will perhaps get a screen cast made up to show it in action.

I'll post details on my blog: http://www.aboutcode.net/

in reply to C# Syntactic Macros

channel9.mdsn.com [channel9.mdsn.com]

Andrew Davey — Mon, 16 Jul 2007 18:50:55 GMT

I just mistyped the Channel9 address... the resulting website totally confused me for a minute. I thought Channel9 had undergone some major reworking over the weekend! :)

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PIE - Podcasts from Internet Explorer [PIE - Podcasts from Internet Explorer]

Andrew Davey — Thu, 22 Mar 2007 22:47:04 GMT

[Warning - this is a self promotion zone!]

I have just released the first version of Pie.
Pie (Podcasts from Internet Explorer) gets the podcasts downloaded by Internet Explorer 7's feed engine and displays them in a handy list.
Download it now

Clicking an show will start it playing. You can create a playlist of all podcasts, or just the new ones.
Pie can also be loaded inside Windows Media Player as a plug-in:

I basically wrote this thing in under a day so it's bound to need more work. My blog is http://blogs.warwick.ac.uk/andrewdavey/ where I tend to write about my developments. Please download and try it out. All feedback is appreciated.

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Possible simple solution to phishing [Possible simple solution to phishing]

Andrew Davey — Tue, 29 Aug 2006 08:28:43 GMT

How about when I sign up to a service, in addition to my email, password, etc, I tell them a second password or passphrase? Then when ever they send out an email to me, they include that password in plain text. Since only me and the company know the password it has to have come from them.

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Mobile phone anti-virus [Mobile phone anti-virus]

Andrew Davey — Fri, 25 Aug 2006 12:26:24 GMT

I just received this text message from Orange (my mobile phone operator):

"Protect your phone with our market-leading anti-virus software from F-Secure. It's free to download and free to use for one week. You can then keep it active for £1.50/month ..."

Geez, is this really the future?! :s

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Selling Windows Form Component [Selling Windows Form Component]

Andrew Davey — Sun, 13 Aug 2006 16:08:17 GMT

Over the past years I've created various tools, components and libraries that I use to make my job easier. I have made some of these open source in a bid to get feedback and involve the community to improve them. Most of the feedback is either "thanks for the great code" or "feature X is broken, please fix". So far no-one has sent me any patches or even contributed to documentation. I try to see what I do on these projects as giving something back, since I use a variety other open source projects (like NUnit, Subversion, etc). However, when I look at my bank balance I do ask myself if it's really worth all my effort.

I have created a windows form tree view control that is data bindable to business objects and datasets. It maintains and updates the "current row" index across all binding contexts. It even supports recursive data structures and can be easily customized. I put a lot of time into the code and am wondering if it is worth trying to sell. It's not a huge control library - so I'd only ask about $20, perhaps more to include the source code. Does anyone know of a good 3rd party site that sells controls on behalf of developers? I could host my own, but I doubt I'd get enough traffic to it. Any suggestions are appreciated.

Thanks :)

in reply to Selling Windows Form Component

Simple Continuous Integration Open Source Projects [Simple Continuous Integration Open Source Projects]

Andrew Davey — Sun, 13 Aug 2006 15:31:27 GMT

Has anyone come across an open source project host that makes it easy to work with by providing continuous integration tools - like cruise control? I am currently using SourceForge to host some open source projects. Whilst SF certainly provides many features they are all very disconnected and hard to use correctly (from an admin point of view as well as users'). Even making a file release is over complex. You have to upload your ZIPs to their anonymous FTP, then navigate thru their awful web interface, find your files in a list of other peoples then find the right button to click to update. I feel as if tools like cruise control, nant, nunit, etc could be put to use to automate all the tedious admin work. A common reply to a bug post from open source coders is "fixed in subversion/cvs" - I'm not suprised they can't be bothered uploading binary releases!
"Release early, release often" becomes a bit of joke - most developers don't want the hassle of checking out the code and compiling it from scratch.

I am aware of new sites like http://code.google.com/hosting/ and http://www.codeplex.com/. Google currently have no binary release system in place, but I like their super-simple interface. It's so refreshing after fighting with SourceForge for so long. I've not had a proper look at CodePlex's features. I know it uses Team Foundation Server. What are people experiences using these services from a project owner point of view?

As a single developer running entire open source projects I really don't want to spend hours fighting with over-complicated project management user interfaces. I wish I could just commit my code to subversion and have the server kick off a nightly build and publish the binaries, etc ready for my users the next day.

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Data Binding Business Objects [Data Binding Business Objects]

Andrew Davey — Sat, 05 Aug 2006 22:51:28 GMT

Quick show of hands:
Who is data binding business (domain model) objects directly to their Windows Forms UI? (maybe BindingSource in .NET 2.0)

Do you feel a little left out compared to the people using DataSets? For example: no built-in support for sorting and filtering in DataGrid?

I'm going to put together a video of my BindingListView library tomorrow. I was wondering if people had some specific gripes I can show and fix using my library.

EDIT
Video now online: http://blw.sourceforge.net/demo.html

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Data Bound Tree View [Data Bound Tree View]

Andrew Davey — Fri, 18 Nov 2005 01:27:49 GMT

Hello Everyone,

I had a go at making my first "screen cast" today. It's showing off my new Data Bound TreeView control. Check it out via my blog here: http://blogs.warwick.ac.uk/andrewdavey/entry/screen_cast_1/

(I know I need to work on making the screen capture a bit cleaner. Hopefully the next one will be better). All feedback is appreciated.

Thanks!

in reply to Data Bound Tree View

Document View Library [Document View Library]

Andrew Davey — Wed, 12 Oct 2005 09:43:16 GMT

If anyone anyone misses the old document-view style application in .NET then check out my new library: http://www.equin.co.uk/appfx/docview/

The Document View Library is a set of interfaces and classes that make putting together a document-view architecture really simple. It supports multiple views of documents and is very flexible and extensible. The library is free for non-commercial/private use.

It was created using .NET 2.0 so you will need a recent beta to run it. The website contains a download of an example application that uses the library. Any feedback would be greatly appreciated. Thanks!

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Using DirectShow to get audio bytes [Using DirectShow to get audio bytes]

Andrew Davey — Thu, 18 Nov 2004 10:41:50 GMT

Hello C9,

Does anyone know how to use DirectShow to get to the stream of WAV data in an audio file (mp3, wma, etc). I want to write a program that generates TRM fingerprints of music, but first I need to be able to send raw wav info to the TRM web service.

I started wading thru MSDN, but quickly started to sink! Google was not much help either :(

Any pointers would be greatly appreciated.

-Andrew

in reply to Using DirectShow to get audio bytes

Creating C# Express Web Services [Creating C# Express Web Services]

Andrew Davey — Fri, 12 Nov 2004 23:31:49 GMT

Hi Niners,

I have worked out how to make web services using C# Express. If anyone would like to know the details post a comment and I'll write up a blog post...

-Andrew

in reply to Creating C# Express Web Services

Strong named assemblies with C# express [Strong named assemblies with C# express]

Andrew Davey — Sat, 30 Oct 2004 21:18:30 GMT

Does anyone know how to make C# Express sign assemblies? Doing this:

[assembly: AssemblyKeyFile(@"d:\projects\AndrewDavey.snk")]

causes a compile warning:

Warning 2 Use command line option '/keyfile' or appropriate project settings instead of 'AssemblyKeyFile'

There is no project settings tab for "Signing".
Do I really have to build everything from the command line? Not very "express" if you ask me...

<c# express version>
8.0.40607.16 (beta1.040607-1600)

in reply to Strong named assemblies with C# express

I HATE this so much [I HATE this so much]

Andrew Davey — Sun, 17 Oct 2004 14:48:44 GMT

Add a WebBrowser activeX control to a form (VS2003).
Make it Navigate to a page that has frames.

add a code that does this:

IHTMLDocument2 doc = (IHTMLDocument2)axWebBrowser1.Document;

object oI;
int len = (int)doc.frames.length;
for (int i = 0; i < len; i++) {
oI = i;
mshtml.IHTMLWindow2 frame = (mshtml.IHTMLWindow2)
doc.frames.item(ref oI);
MessageBox.Show(frame.name);
}

So it should display the name of each frame in the document - but NO! It throws some stupid System.UnauthorizedAccessException. WTF?!

Any ideas?

Is it some kind of SP2 problem?

in reply to I HATE this so much

I really need help with this [I really need help with this]

Andrew Davey — Sun, 10 Oct 2004 13:06:14 GMT

http://channel9.msdn.com/ShowPost.aspx?PostID=24914#24914

Thanks :)

in reply to I really need help with this

Internet Explorer Plug-in [Internet Explorer Plug-in]

Andrew Davey — Fri, 08 Oct 2004 12:22:13 GMT

Does anyone have any good resources for creating plug-ins for Internet Explorer. I want to write some code that intercepts clicking a hyperlink (for an RSS feed) and invokes a sepearate application.

Any ideas?

- Andrew

in reply to Internet Explorer Plug-in

The Ultimate Aggregator [The Ultimate Aggregator]

Andrew Davey — Tue, 24 Aug 2004 21:07:05 GMT

The range of content being provided via RSS feeds is growing everyday. We now have text, audio, photos and even video being published using this pervasive media. Simple text aggregators are fine for reading a few news feeds and weblogs, but people will want to do more with the available content. A prime example is Adam Curry’s iPodder script to automatically upload MP3s found in RSS feeds to his iPod. RSS provides a single channel for all different forms of content to flow through. So surely it would be good to have a single engine to process and control that flow; an extensible engine that can grow to handle the ever increasing types of content.

I would like to propose the creation of a new content aggregator. The features that it should have include:

Feed parsers to translate different formats into a standard item collection
Feed filters to make browsing large amounts of items easy
Feed processors that perform custom actions such as upload audio to iPods, post weblog entries, etc
Feed presenters that provide custom user interfaces to best suit the type of media in the feeds.

So is anyone out there interested in some sort of open source ultimate aggregator? This could potentially be a big project so I’d love to get feedback and ideas from the rest of the community, either here or at http://www.equin.co.uk/undoprovider.htm
Andrew

in reply to Undo/Redo Framework