June 2008 - Mike Taulty's Blog

Following on from this last post , if I start to edit the data in the grid and change some value then the property value will change in the underlying class but nothing else will happen. That is, the NorthwindEntities class which is managing my data for me client-side ( which is derived from DataServiceContext ) isn't going to be aware of those modifications. Why not? If we have a look at a property on a generated class such as this one for the CompanyName on the Customers class; public string CompanyName { get { return this ._CompanyName; } set { this .OnCompanyNameChanging( value ); this ._CompanyName = value ; this .OnCompanyNameChanged(); } } Now, OnCompanyNameChanging and OnCompanyNameChanged are partial methods with no implementation by default so nothing's going to happen when something like the DataGrid changes a value such as CompanyName. Similarly, the generated entity classes such as Customers do not implement INotifyPropertyChanged which means that changes in the data will not be reflected in the UI...

Someone asked me today how you'd go about ensuring that timestamp columns in your database tables show up in your Entity Framework EDMX file with a Concurrency=Fixed attribute on them. That is - it's very likely that the timestamps are there on the table to enforce concurrency so why not default their Concurrency value to "Fixed" ? It's a good question but it's not something that the tooling does as far as I'm aware so I tried to have together some LINQ to XML code that would make an attempt at it. I don't claim that this is correct at all but it might be a starting point for this and similar, related pre-processing that you want to do on an EDMX file. static void Main( string [] args) { XElement edmxFile = XElement.Load(args[0]); XNamespace edmxNs = XNamespace.Get( "http://schemas.microsoft.com/ado/2007/06/edmx" ); XNamespace ssdlNs = XNamespace.Get( "http://schemas.microsoft.com/ado/2006/04/edm/ssdl" ); XNamespace mapNs = XNamespace.Get( "urn:schemas-microsoft-com:windows:storage:mapping:CS" ); XNamespace csdlNs...

One of the things that I've been meaning to experiment with around the MultiScaleImage control in Silverlight 2 Beta 2 was the ability of the control to request its image tiles from an alternate source. That is, in Silverlight 2 Beta 2 you can create your own type to provide tiled images; public class MyTileSource : MultiScaleTileSource { public MyTileSource( int imageWidth, int imageHeight, int tileSize) : base (imageWidth, imageHeight, tileSize, tileSize, 0) { this .tileSize = tileSize; this .imageWidth = imageWidth; this .imageHeight = imageHeight; } and then you can set this as the Source of a MultiScaleImage control as in; msi.Source = new MyTileSource( int .Parse(txtImageWidth.Text), int .Parse(txtImageHeight.Text), int .Parse(txtTileSize.Text)); and then the MultiScaleImage control will call your code when it wants to load up tiles. Now...in Silverlight 2 Beta 2 there's not so much that you can do around drawing bitmapped images. Joe Stegman has a sample here that does do dynamic image generation but he...

If you work for Microsoft in the UK then please click here and hit send from a recognisable email account. I'm curious as to how many people within the UK company read my blog. Thanks :-) Updated on 19th June to change the title and say that the current response rate is 22 people .

Something that I came across today - if you're trying to surface a LINQ to SQL data source via the latest build of ADO.NET Data Services and you're running datasvcutil.exe on the metadata of the service then you might find yourself with a whole bunch of errors. Here's a sample of what I was getting this morning; error 7001: Schema specified is not valid. Errors: $metadata(0,0) : error 0005: The 'Namespace' attribute is invalid - The value '' is invalid according to its datatype ' http://schemas.microsoft.com/ado/2006/04/ edm:TNamespaceName' - The Pattern constraint failed. For me, I resolved this by just making sure that I revisited my DBML diagram for LINQ to SQL in Visual Studio and set the "Entity Namespace" property for code generation. That is, click on the white-space of the diagram; to make sure that you have the diagram rather than a particular entity set selected. Then hit F4 for the properties; and give yourself a namespace and all the errors seem to go away reasonably quickly :-)

Silverlight 2 Beta 2 is available - see http://www.silverlight.net for details on how to download it and for the list of breaking changes between Beta 1 and Beta 2. Here's where to get the runtime and the tooling ( SDK and Visual Studio ) Here's where to get Expression Blend 2.5 June CTP ( you're going to like this one if you've been hoping for template editing :-) ) Here's where to get the Deep Zoom Composer , or follow this link . You'll find that if you view your Silverlight Beta 1 applications with Silverlight Beta 2 then they won't display - you'll need to update those applications in order to work with Beta 2 and that is going to include rebuilding/reworking the code and changing the hosting page to request Beta 2. Mike and I made a bunch of videos for Silverlight Beta 1 and an application to display them. We've now updated those videos for Beta 2 and also ported the viewing application. I've removed the original player and the videos that it was displaying but the URL for the application remains the same...

I watched the TechEd (US Developers) Keynote just yesterday. Tech·Ed NA Developers Keynote delivered by Bill Gates and you can see more on the TechEd Online site including a changing set of videos at the bottom of the page such as these ones which popped up when I visited the site; Which kind of freaked me out as I wasn't expecting to be greeted by my own ugly mug when hunting down resources from TechEd US ( that video is from TechEd Europe, you wouldn't believe how hard it is for someone like me to get to a conference like TechEd US ). During the keynote I started to get a little bit panicky. There's a lot of new stuff coming on top of all the new stuff that's already coming :-) I get a bit edgy when I know there's lots of new things around that I should probably know about but don't yet know about. Some of the things mentioned were a little less new than others but still pretty exciting. There was mention of Silverlight 2 Beta 2 of course and also some talk about the improvements to WPF in .NET Framework V3...