.NET Development

Window 7 Launch Event – Ft Lauderdale / Miami

Dave Noderer — Thu, 24 Sep 2009 13:53:08 GMT

I'm at the Windows 7 launch event in Ft. Lauderdale working the community booth with Alex Funkhouser, Kathy Malone and a brief celebrity appearance by Shervin Shakibi,

Here are some pictures I took this morning!

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Book Review - Effective REST Services via .net

Dave Noderer — Mon, 21 Sep 2009 12:25:41 GMT

I just got done reading "Effective REST Services via .NET" by Kenn Scribner and Scott Seely. ISBN-13: 978-0-321-6125-7

I've been hearing a lot about restful services and have absorbed the basics by osmosis but always like to read a book to cement the ideas more clearly.

This book does a good job of that but goes a few steps further.

A few things I particularly liked were:

- Review of http and how the internet works, things I don't pay much attention to any more!

- While presenting "pure" restful services also pointing out practical applications that might divert a bit.

- This book has a very good tutorial on asynchronous programming.

- The examples are good if a bit complicated but do build on each other.

- Senarios and examples cross both windows and web development.

- All in C# but was easy enough to read it looks like C# only books are the future.

It was worth the read and I have a much better understanding of restful services.

Programming Entity Framework – Julie Lerman – O’Reilly Media

Dave Noderer — Sun, 17 May 2009 16:50:56 GMT

Long past due is a review of Julie’s book, Programming Entity Framework, ISBN 978-0-596-52028-1

Julie adopted Entity Framework early on, from before it was even available to most MVP’s. This book is a reflection of that involvement with the product and the product teams over the past few years.

This 23 chapter, 750+ page book covers a lot of ground and provides a great reference book for almost everything entity framework related.

The first few chapters introduce the framework and will give you a good working knowledge of how to use it. A few other chapters like using the framework with stored procedures and the entity data source control are a good place to start.

What was amazing to me was the variety of ways that you can (in some cases have to) query the entities with Entity SQL LINQ and method based queries. I’m hoping this is more related to the early stage of the entity framework and eventually the options required to get at various features would focus on a single methodology.

The base of the entire framework is the entity model and is usable in theory with or without a sql server backing store. The “wizard” type of tools currently drive off of SQL Server which is fine with me because I have always started with the data model. The modeling language does allow you to go further and add both relations and entities which don’t / can’t exist in a purely relational model.

Once you leave the vanilla scenario of matching your entity to the database the workload goes way up and there is a lot of detail in the model and storage parts of the framework you will have to be familiar with and manipulate.

The good news is that this book goes through all of the above scenarios and has something about all of the related subject.

Another nice feature is that all the examples are in both vb and c#.

In this light I highly recommend this book for both an introduction to the Entity Framework and also as a reference book you will use over time as you need additional features.

For more information visit Julie’s website: http://www.thedatafarm.com/main.aspx

No scoping for SQL Server stored procedures…

Dave Noderer — Thu, 07 May 2009 14:28:19 GMT

It’s always nice to learn something new…

Today I learned that variables in SQL Server stored procedures have no scope rules.

Take this example:

--
Declare @Outer int
Set @Outer = 1

While 1 = 1
begin
    Declare @Inner int
    Set @Inner = 2
    break
end
Select @Outer, @Inner

As a developer I expected that a new “instance” of @Inner would be created on each iteration of the loop and that the ending select would actually get an error saying that there was no variable @Inner.

But this is not true, all variables have a scope of the batch in which they are declared, code blocks be damned!

Lesson learned… re-initialized each loop of the procedure and everything works as expected.

Embarrassing as I’ve been writing stored procedures for 15 years…

Ft Lauderdale Online – 1st Meeting

Dave Noderer — Wed, 06 May 2009 07:44:00 GMT

We had the first online version of the Ft Lauderdale developer group meeting tonight.

Eighteen people were online but i was the only one with a web camera… I hope more start getting the video cranked up!

The topic was Introduction to MVC and was suppose to be given by Jim Zimmerman out of Tampa but he called at 5:30 (for the 6:30 meeting) reporting that his laptop power brick was toast and he was out of juice. He had tried to get another one but at this point he was dead in the water because his presentation was on the laptop too….

So he gave David Hayden a call who agreed to do the presentation as they are planning to do some of this for the TampaDev.org group too. That group is focused exclusively on MVC, at least for now.

David did a great job of just going through the basics of an mvc app, no power points, just use visual studio and make a project. We dug into the T4 templates a bit and also validation. There were a number of questions that sparked additional discussion.

I used live meeting to record it all to.

A link to the recorded meeting can be found here: https://www311.livemeeting.com/cc/mvp/view?cn=&id=PZ6Z2C&pw= no key is required.

More information, video’s, etc at: http://asp.net

Lots more info at the Tampa Bay Developers MVC group: http://tampadev.org

SQL Server 2008 Filestream and vb.net

Dave Noderer — Wed, 05 Nov 2008 13:37:06 GMT

I’ve become interested in a few aspects of SQL Server 2008. One is the new FILESTREAM datatype.

The basic idea is to have a SQL datatype you can use in queries and searches and is managed by SQL but which does not have any particular size limitation.

There are a number of articles on the multiple steps it takes to setup a database to utilize the new FILESTREAM features. I’m not going to cover that in this article. I highly recommend reading Paul Randal’s white paper on the subject, now published on MSDN: http://msdn.microsoft.com/en-us/library/cc949109.aspx. Both he and Kim Tripp have lots of great SQL server content online at www.sqlskills.com. Paul also has some performance graphs of that will give you an idea of when to use FILESTREAM vs image or text.

Unfortunately there is very little on how to actually utilize the FILESTREAM from a programming standpoint. Most of them show how to utilize Win32 API and the SafeFileHandle, I only found one (I’m sure there are more) that talked about using the managed interface, SQLFileStream. You can find that paper at: http://blogs.microsoft.co.il/blogs/bursteg , this was also all C#, not VB.

So I have created a vb project which illustrates using FILESTREAM… The presentation, visual studio project and sql script can all be found here: http://www.fladotnet.com/downloads/SQL2k8TidBits_20081104.zip

One thing I found is that the old Text, nText and image sql types are being replace by varchar(max) and varbinay(max) which all have a size limitation of 2 gb.

The FIlestream datatype is really just a flagged varbinary(max) column with a tag of FILESTREAM. The sample I've made uses a table declared as follows:

CREATE TABLE FSDemo.dbo.FSDemoTable
(
    [Id] [uniqueidentifier] ROWGUIDCOL NOT NULL UNIQUE,
    [Description] varchar(50) null,
    [JPG] VARBINARY(MAX) FILESTREAM NULL
)

Besides the FILESTREAM tag on the column, each table containing a filestream column must have a uniqueidentifier (guid) column.

After inserting a row (see the 1_3_InsertData.sql script) the program will need two things in order to access the filestream data.

First is the path as defined by sql server. This is a reference to the file (not accessible directly through normal system.io) that contains the data for the row/column selected. A simple query of this for the table above is:

Select JGP.PathName() from FSDemoTable Where ID = @ID

This will give you a path: \\PLOVER2V3\SQL2K8\v1\FSDemo\dbo\FSDemoTable\JPG\0925394D-79D7-41FB-B438-9EA85C0FA232

The trailing 79D7-41FB-B438-9EA85C0FA232 is the @ID above but you won’t find a file by that name.

The second piece of information is the transaction context. To utilize filestream for reading or writing, you need to establish a transaction and then get the transaction context, a 16 byte array back from the db to pass into the SQLFileStream call. You can see this in the 1_4_FSGet.sql script and it looks like this:

select JPG.PathName(), GET_FILESTREAM_TRANSACTION_CONTEXT() from dbo.FSDemoTable WHERE id = @id

Now for code… to write to a file stream the annotated code is below. I’m sure there are many improvements to be made but the idea is to illustrate the steps.

For this sample, a description of the file (photos) and the actual byte array containing the jpg file are passed to this routine for writing and an array of bytes returned after the read. Once you get the path and context, the sqlfilestream operations are basically normal file IO.

Public Sub WriteFileStream(ByVal Description As String, ByVal SourceBytes As Byte())
    Dim cn As SqlConnection
    Dim tx As SqlTransaction = Nothing
    '
    Try
        '''''''''''''''''''''''''''''''''''''''''''''
        ' Open a connection and start a transaction
        '''''''''''''''''''''''''''''''''''''''''''''
        '
        cn = New SqlConnection(ConnectionStrings("conFSDemo").ToString)
        cn.Open()
        tx = cn.BeginTransaction
        '
        '''''''''''''''''''''''''''''''''''''''''''''
        ' Insert empty blob in the database
        '''''''''''''''''''''''''''''''''''''''''''''
        '
        Dim cmd As New SqlCommand("FSInsert", cn, tx)
        cmd.CommandType = CommandType.StoredProcedure
        cmd.Parameters.Add(New SqlParameter("Description", Description))

        Dim r As SqlDataReader = cmd.ExecuteReader(System.Data.CommandBehavior.SingleRow)
        '
        '''''''''''''''''''''''''''''''''''''''''''''
        ' Read the id and sql path back from the proc
        '
        '''''''''''''''''''''''''''''''''''''''''''''
        '
        r.Read()
        Dim ID As String = r(0).ToString
        Dim path As String = r(1).ToString
        r.Close()
        '
        ''''''''''''''''''''''''''''''''''''''''''''''
        ' Get the transaction token, required for filestream operations should add this from the previous proc…
        ''''''''''''''''''''''''''''''''''''''''''''''
        '
        Dim cmd2 As New SqlCommand("SELECT GET_FILESTREAM_TRANSACTION_CONTEXT()", cn, tx)
        Dim obj As Object = cmd2.ExecuteScalar()
        '
        Dim txCtx As Byte()
        txCtx = CType(obj, Byte())
        '
        '''''''''''''''''''''''''''''''''''''''''''''
        ' Open the special managed "SQLFileStream" and write the bytes
        '''''''''''''''''''''''''''''''''''''''''''''
        Dim fs As New SqlTypes.SqlFileStream(path, txCtx, FileAccess.Write)
        '
        fs.Write(SourceBytes, 0, SourceBytes.Length)
        fs.Close()
        '
        tx.Commit()
        '
    Catch ex As Exception
        '
        tx.Rollback()
        '
    End Try
    '
End Sub

To Read the image the code is:

Public Function ReadFileStream(ByVal ID As Guid) As Byte()
    Dim cn As SqlConnection
    Dim tx As SqlTransaction = Nothing
    Dim txCtx As Byte()
    Dim SQLpath As String
    '
    Try
        '''''''''''''''''''''''''''''''''''''''''''''
        ' Open connection and establish transaction context
        '''''''''''''''''''''''''''''''''''''''''''''
        '
        cn = New SqlConnection(ConnectionStrings("conFSDemo").ToString)
        cn.Open()
        tx = cn.BeginTransaction
        '
        '''''''''''''''''''''''''''''''''''''''''''''
        ' Retrieve Path and transaction context of the filestream
        '''''''''''''''''''''''''''''''''''''''''''''
        '
        Dim cmd As New SqlCommand("FSGet", cn, tx)
        cmd.CommandType = CommandType.StoredProcedure
        cmd.Parameters.AddWithValue("@ID", ID)

        Dim r As SqlDataReader = cmd.ExecuteReader(System.Data.CommandBehavior.SingleRow)
        '
        r.Read()
        SQLpath = r(0).ToString()
        txCtx = r(1)
        r.Close()
        '
        '''''''''''''''''''''''''''''''''''''''''''''
        ' Read the file
        '''''''''''''''''''''''''''''''''''''''''''''
        '
        Dim fs As New SqlTypes.SqlFileStream(SQLpath, txCtx, FileMode.Open, FileOptions.None, 0)
        Dim Buf(fs.Length) As Byte
        '
        fs.Read(Buf, 0, Buf.Length)
        fs.Close()
        '
        tx.Commit()
        '''''''''''''''''''''''''''''''''''''''''''''
        ' Return the bytes
        '''''''''''''''''''''''''''''''''''''''''''''
        '
        Return Buf ' return the bytes
        '
    Catch ex As Exception
        '
        tx.Rollback()
        '
        Return Nothing
        '
    End Try
    '
End Function

Software SDR - the RXTX+Xtall v6.3 kit

Dave Noderer — Mon, 25 Aug 2008 00:14:13 GMT

I've started construction of a HF (High Frequency vs UHF/VHF ham bands) radio that will cover ~ 1.8 to 30 mhz. it is a kit put together by Tony Parks and supported by a very active community: http://groups.yahoo.com/group/softrock40

I tell you, either my eyes have gone downhill (for sure) or those surface mount components got much smaller in the 20 years since I last worked in a lab every day.

This would be especially hard without community driven detailed construction notes: http://golddredgervideo.com/wb5rvz/RXTX_V6_3/index.htm

I'll make comments here and post pictures as I go!

Pictures at: http://geekswithblogs.net/dnoderer/gallery/8589.aspx

I'm almost at a stage where I can point some software at this thing but a while before I will be able to do much with it.

Dave makes Computer World

Dave Noderer — Fri, 16 May 2008 18:03:10 GMT

http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=9085698&pageNumber=1

South Florida Code Camp 2008 - 2/2/2008

Dave Noderer — Thu, 24 Jan 2008 20:39:41 GMT

FREE - 4th Annual South Florida Code Camp - Register Now - Spaces are going fast!

To attend this free, all day .NET Developer mini-conference register at: http://www.clicktoattend.com/?id=122048 ! The Code Camp will be held on Saturday 2/2/2008 and include breakfast, lunch, giveaways, valuable raffle items and of course lots of great content!

The sessions are now listed on the agenda page. A big thanks to all the speakers that have stepped forward and volunteered to come speak at their own expense. We have already scheduled 70 of 72 sessions. There will be something for everyone... from the person who is new to .net to advanced architecture and software process sessions. For the second year we will have an all Spanish track. Dedicated tracks include "Into to .NET", "Silverlight" and "Agile / CI". Sessions include Ajax, MVC, Visual Studio 2008, Powershell, Windows Workflow and .NET reflection.

Find more information at http://codecamp08.fladotnet.com . We have many sessions lined up. The track chairs will get them organized and on the website agenda over the next couple of weeks.

Install Fest at Devry on 12/11/2007

Dave Noderer — Wed, 12 Dec 2007 12:53:11 GMT

WOW!! That was fun!

The room was packed with 50 people and their machines loading Visual Studio 2008 while Joe Healy (www.devfish.net) talked about various Visual Studio Features.

People started arriving at 5PM with Ed Hil from DeVry checking identiies and dna samples. Up to 6:30 PM only the 1st 50 on the list who showed up with a machine got a copy. During this time we kept a list of people as they arrived and the order they arrived in. At 6:30 we opened it up and had just enough copies for everyone!

As each person finished, we took their picture with their completed install screen which Joe will post on his website.

But... this was no ordinary presentation.. the room was "buzzing" all night as people are talking about the installs and other topics too. A few people had problems and were awared the mechanical "bug" by Joe as a prize but most were able to finish. One person had a big server box and 24" monitor! Another had an older system which unfortunately did not have a DVS player.

A few of the DVD's were bad but everyone shared and more importantly got the code for the boxed version.

Everyone got a Visual Studio 2008 T-shirt and thanks to Sherlock Technologies (www.sherstaff.com) and Mike Wasserman, we had pizza and soda.

A big big thanks to Joe Healy, our Microsoft Developer Evangalist for making this possible... Hey now we know how to fill the room each month, give everyone $600 of free software!

See photos through Joe Healy's blog: http://www.devfish.net/FullBlogItemView.aspx?BlogId=473