Archives
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Declarative programmation will bloom with ASP.NET 2.0 auto-compilation
You may already know that, but ASP.NET 2.0 introduces a new Code directory (or Application_Code, the name is not final yet) that enables you to just deploy the source files of your libraries, and they will get compiled on-the-fly. What you may not know is that you can extend this by creating your own build providers.When I first learned about the extensibility of the auto-compilation, I immediately thought about how an Object/Relational mapping tool could take advantage of it and generate the DAL transparently on-the-fly from the XML mapping file. It would make it marvelously transparent and easy to use, update and manage. An additional bonus is that any change to the xml file would immediately result in Visual Studio Intellisense picking up the change and displaying the new types. Just perfect.It seems like I'm not the only one who thought about that: here's an article from Fritz Onion that explains exactly how to do this now, with the public beta of ASP.NET 2.0. Check it out, it works now.The possibilities are endless. For example, a business rule engine could use it, or a form generator.Play with it, invent great new applications, and if you find anything limiting you in doing so, just tell us about it. Now is the right time. -
Optimize your images
It is vitally important that we optimize all the images we ship as resources in the framework: these images will potentially be downloaded several times on each of the pages our users build using the controls that use them.
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Die, NumLock, Die!
Why do we still have this stupid NumLock key on modern keyboards? Who still uses it with all of the unlocked keys duplicated about half a centimeter to the left? Hello? Keyboard designers? Please get rid of it now. Everybody hates seeing the cursor go crazy when all they wanted to do was to type a number.Now, the people who design keyboards at Microsoft have recently come up with a new way to torture us: the F Lock key. They've decided that we needed new fixed function keys for common tasks such as save or print. This is all very well and I'm sure that having access to these functions with just one keystroke and without having to know complex ctrl key combinations is very useful to disabled persons. But why did they have to put these on our function keys?? Just add new keys, but don't replace useful keys that we're used to. Of course, the new key meanings are on by default and you need to hit F Lock to restore the old F keys. And naturally, every time you reboot, you have to hit it again.Die, F Lock, die!Actually, why not make these lock keys real switches if you really want to keep them? After all, they're a matter of personal preference that you just want to set once and forget about. So they could be real switches that you can't accidentally hit. That would be so much better, and it would get rid of the stupid problem that wireless keyboards have which is that they can't display the status of these keys for power consumption reasons.Well, in fact, they could also be software settings in the keyboard drivers for all I know.Finally, what's with the PrtScn key? Whenever I want to do a screen copy, I have to figure out some strange combination of F Lock, Ctrl, Alt and Shift to get the right result. And what does SysRq mean? Does any application still react to ScrLk?Last minute: To get your F keys back, try this: http://www.mvps.org/jtsang/flock.html -
The case of the missing data source
If you've used the beta version of ASP.NET 2.0 a little, the Menu and TreeView controls in particular, you may have noticed that the datasources they consume are different from those that GridView or FormView use. But of course, Menu and TreeView have to use hierarchical data sources, whereas other controls use tabular data sources.Tabular data sources that you get out of the box are mainly SqlDataSource and ObjectDataSource. Of course, you can also build your own data source (more on this in later posts). The nice thing is that with ObjectDataSource, you can potentially get data from any data store.Now, for hierarchical data sources, you've got XmlDataSource and you've got SiteMapDataSource, and... and that's it. So if you want to populate a Menu or TreeView from a database, you'll pretty much have to do it from code.Enter CompositeHierarchicalDataSource... This control I've developed on my free time (which is mainly composed of an aggregation of my serious work's compilation time) composes several tabular data sources into one hierarchical data source using relations.Here's a simple page that displays a menu that takes its data from a composition of one ObjectDataSource and two AccessDataSources:
<%@ Page Language="C#" debug="true" %>
<%@ Register Namespace=MyControls.DataSources.CompositeHierarchicalDataSource TagPrefix=my %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>CompositeHierarchicalDataSource</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<my:CompositeHierarchicalDataSource runat=server ID=Composite1 RootViewName="Categories:DefaultView">
<DataSources>
<asp:ObjectDataSource ID="Categories" Runat="server" TypeName="Categories"
SelectMethod="GetCategories" />
<asp:AccessDataSource ID="SubCategories" Runat="server" DataFile="~/data/things.mdb"
SelectCommand="SELECT [Id], [CategoryId], [Name] FROM [SubCategories]"/>
<asp:AccessDataSource ID="Things" Runat="server" DataFile="~/data/things.mdb"
SelectCommand="SELECT [Id], [SubCategoryId], [Name], [Description], [Url] FROM [Things]"/>
</DataSources>
<Relations>
<my:Relation ParentDataSourceId="Categories" ParentView="DefaultView" ParentColumns="value"
ChildDataSourceId="SubCategories" ChildView="DefaultView" ChildColumns="CategoryId"/>
<my:Relation ParentDataSourceId="SubCategories" ParentView="DefaultView" ParentColumns="Id"
ChildDataSourceId="Things" ChildView="DefaultView" ChildColumns="SubCategoryId"/>
</Relations>
</my:CompositeHierarchicalDataSource>
<asp:Menu Runat=Server ID=myMenu DataSourceID=Composite1>
<DataBindings>
<asp:MenuItemBinding DataMember="Categories:DefaultView" TextField="text" ValueField="value" />
<asp:MenuItemBinding DataMember="SubCategories:DefaultView" TextField="Name" ValueField="Id" />
<asp:MenuItemBinding DataMember="Things:DefaultView" TextField="Name" ValueField="Id"
ToolTipField="Description" NavigateUrlField="Url" />
</DataBindings>
</asp:Menu>
</div>
</form>
</body>
</html>The nice thing is that you can in principle use any tabular data source to build your hierarchical data source. In principle only: this is still a proof of concept and is currently limited to SqlDataSources, ObjectDataSources whose views return DataViews, and datasources whose views implement ITabularDataSourceView. Another problem it currently has is that it loads all of the data at one time. It would be nice to have lazy loading for populate on demand TreeView scenarios.It's shared source, so you're free to use and modify the code as you wish. Enjoy!In future posts, I'll explain how it works in details, which should make a nice tutorial on how to develop your own hierarchical data source (hint of other missing data sources: LdapDataSource, FileSystemDataSource).TheGotDotNetCodePlex workspace for this data source can be found here: -
Number geeks!
Robin Debreuil has a great post about how the world would be a better place if we had four fingers like the Simpsons (or virtually any cartoon characters). He doesn't say anything about the yellow color or the rubbery hair, but it would sure look cool too.His article is amazingly well documented and thought through. You can see that this guy has been thinking about building a new numbering system for years. Very impressive. And very geeky too, in a hilarious kind of way.Unfortunately, his proposition for easier arithmetics has even less of a chance to be widely adopted as, say, the US has to adopt the hugely superior metric system or Swatch has to impose its "internet time".So it is a total waste of energy, totally useless, impressively time-consuming and funny at the same time.And thus highly recommended reading.A few things worth noting and objections, though:- I would actually have loved a numeric system where 4233 sounds like "butthole sniff sniff". How boring would the solar system be if we didn't have Uranus?- A complete tutorial with exercises and a diploma at the end would be great (there are exercises at the end of the paper, but that's not enough: I want to learn)- As has been noted in the comments, the balanced ternary system is surprisingly good too. Any chance of mixing the two for a balanced ternary bioctal system? And for a better name than that?- I'll be saying bioctal too from now on instead of hexadecimal- You're completely mad to spend so much time on trying to improve everyone's life whereas you should be working on your SWF/C# project- If we forget about one of our fingers, how easier is it to count on them? Anything you can't do with the decimal system?- Bioctal sounds like a french anti-acne medication, which is ok as geeks keep their acne quite late.