Identity Interface I should know better

Microsoft XAML Toolkit and XamlDom released

Today the XAML team announced the availability of the Microsoft XAML Toolkit
http://code.msdn.microsoft.com/XAML

It has been taken down due to signing issues, but will be back soon.

This will allow many things

A Dom representation of the Xaml control tree.
Use Linq against the XamlDom, similar to XLinq for XDocument
It is going to be very useful for tools like XAML Designers or Static Analysis.
We can also do some XamlDom functional construction.

PLinq Performance Tip

When using PLinq
Memory Allocations can be the bottleneck.

Anonomous types/reference types are allocated on the heap and will have to be garbage collected.
The garbage collector was designed with low latency/fast UI thread design considerations.
Try to use value types.
Or in the app.config add

<gcserver enabled="true"/>

This enables server mode garbage collection.
Typically workstation mode gc is the fastest, but when we deal with parellism and garbage collection across multiple processors server garbage collection can reap significant performance improvements.

Microsoft Codename Dallas

Yesterday at the PDC Microsoft continued with their one screen one OS initiative and introduced Windows App Fabric, and Codename Dallas.

Dallas is something of an information repository that you can go to, to find the data you would like to use.
Once you found the data, you can browse the data.
Connect to it using Excel.
Slice and dice it with Excel.
or Generate your own proxy class to process the data in code.

Stay tuned, I plan on getting in on the CTP and developing something cool with the technology.

Sql Server Compact – Access to the database file is not allowed.

Lately I have been playing with some small client apps, just kicking the tires on a few of the new microsoft technologies.

For the underlying database I chose Sql Server Compact Edition. Since I am using Linq to Entities, stored procedure support is not necessary.

I wrote a few tests against the database and found that the database was not being deployed along with the tests.  Here is app config entry |DataDirectory|\DataLayer\PhotoStore.sdf. 

I copied that from the Common Library, when the test was ran the entry parsed into  TestResults\Jon_JON-PC 2008-10-20 18_57_13\Out\DataLayer\PhotoStore.sdf

The first error was the obvious file not found error.

My first instinct was just to try and copy it to a common directory. I received the exception below.

System.Data.EntityException: The underlying provider failed on Open. --->  System.Data.SqlServerCe.SqlCeException: Access to the database file is not allowed. [ File name = C:\Users\Jon\Documents\PhotoStore.sdf ].

Resolutions

1. Turning off UAC.

2. Point the tests app.config to the database file in the corresponding app directory.

3. Run Visual Studio as administrator.

4. Create a build task to deploy the database in the test directory (TestResults\Jon_JON-PC 2008-10-20 18_57_13\Out)

I think the reason this is happening is because of the LUA model of security. When I copy the data file into  directory like Users/JonShern/Documents by default the test process is running as a least privileged user, so it not able to write to this file.  Admittedely my understanding of the inner working of security are lacking, seems like it just ends up to be the guess and test method of problem solving:(

I think 1,2 and 3 seem a little hackish to me. But man to write a build task for a little app is just overkill.

Here is a code sample that someone is using for deployments.

SecurityIdentifier sid = new SecurityIdentifier( WellKnownSidType.BuiltinUsersSid , null );

FileSecurity dbSec = File.GetAccessControl( dbFile );

dbSec.AddAccessRule( new FileSystemAccessRule( sid , FileSystemRights.Write, AccessControlType.Allow ) );

File.SetAccessControl( dbFile , dbSec );

References

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1892312&SiteID=1

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=3455426&SiteID=1