LINQ and blobs

[=?Utf-8?B?SmFtZXMgUGFnZQ==?=]

Hi all another LINQ question!!

to retrieve and display sql varbinary images I currently use the following
code:

Imports System.Data.Sql Client
Imports System.Drawing
Imports System.Drawing. Imaging
Imports System.IO



Partial Class ShowPicture
Inherits System.Web.UI.P age

Protected Sub Page_Load(ByVal sender As Object, ByVal e As
System.EventArg s) Handles Me.Load
Dim PictureID As Integer =
Convert.ToInt32 (Request.QueryS tring("PictureI D"))

'Connect to the database and bring back the image contents & MIME
type for the specified picture
Using myConnection As New
SqlConnection(C onfigurationMan ager.Connection Strings("ImageG alleryConnectio nString").Conne ctionString)

Const SQL As String = "SELECT [MIMEType], [ImageData] FROM
[Pictures] WHERE [PictureID] = @PictureID"
Dim myCommand As New SqlCommand(SQL, myConnection)
myCommand.Param eters.AddWithVa lue("@PictureID ", PictureID)

myConnection.Op en()

Dim myReader As SqlDataReader = myCommand.Execu teReader
If myReader.Read Then
Response.Conten tType = myReader("MIMET ype").ToString( )
Response.Binary Write(myReader( "ImageData" ))


End If
myReader.Close( )
myConnection.Cl ose()
End Using
End Sub


End Class

I'm now trying to use LINQ to replace the sql elements. Can anyone help me
convert the above using LINQ?

[=?Utf-8?B?SmFtZXMgUGFnZQ==?=]

RE: LINQ and blobs

After a bit of digging I've found a solution let me know what you guys think!

Here's the new code - including a method to proportionaly display the
resultant image:

Imports System.Data.Sql Client
Imports System.IO
Imports System.Drawing
Imports System.Drawing. Imaging
Imports System.Data.Lin q


Partial Class showPicture
Inherits System.Web.UI.P age


Protected Sub Page_Load(ByVal sender As Object, ByVal e As
System.EventArg s) Handles Me.Load
Dim imageID As Integer =
Convert.ToInt32 (Request.QueryS tring("PictureI D"))

Dim db As New DataClassesData Context()

Dim query As Binary = (From x In db.pictures Where x.ID = imageID
Select x.image).Single ()

Dim imgContent As Byte() = query.ToArray()
Response.Conten tType = ("image/jpeg")

'set the size of the desired thumbnail in px
Dim thumbWidth As Integer = 200
Dim thumbHeight As Integer = 200

Dim s As New MemoryStream(im gContent)


Dim image1 As New Bitmap(s)

Dim bmpOut As System.Drawing. Bitmap

Try
Dim bmpIn As New Bitmap(s)
Dim bmpFormat As ImageFormat = bmpIn.RawFormat
Dim calcRatio As Decimal
Dim thumbNewWidth As Integer = 0
Dim thumbNewHeight As Integer = 0

If bmpIn.Width bmpIn.Height Then
calcRatio = CDec(thumbWidth ) / bmpIn.Width
thumbNewWidth = thumbWidth
Dim thumbHeightTemp 1 As Decimal = bmpIn.Height * calcRatio
thumbNewHeight = CInt(thumbHeigh tTemp1)
Else
calcRatio = CDec(thumbHeigh t) / bmpIn.Height
thumbNewHeight = thumbHeight
Dim thumbWidthTemp2 As Decimal = bmpIn.Width * calcRatio
thumbNewWidth = CInt(thumbWidth Temp2)
End If

bmpOut = New Bitmap(thumbNew Width, thumbNewHeight)
Dim g As Graphics = Graphics.FromIm age(bmpOut)
g.Interpolation Mode =
System.Drawing. Drawing2D.Inter polationMode.Hi ghQualityBicubi c
g.FillRectangle (Brushes.White, 0, 0, thumbNewWidth,
thumbNewHeight)
g.DrawImage(bmp In, 0, 0, thumbNewWidth, thumbNewHeight)

bmpIn.Dispose()
Catch
Return
End Try

Try
bmpOut.Save(Res ponse.OutputStr eam,
System.Drawing. Imaging.ImageFo rmat.Jpeg)
Catch
Finally
bmpOut.Dispose( )
End Try
End Sub
End Class


This seems to work!

[bruce barker]

Re: LINQ and blobs

why did you switch to linq for this query?

linq much less efficient for a simple query like this. at runtime linq
will read the parse tree generated from the query, then convert it to a
sql string, then call the same code you wrote in the first place.


-- bruce (sqlwork.com)




James Page wrote:

After a bit of digging I've found a solution let me know what you guys think!
>
Here's the new code - including a method to proportionaly display the
resultant image:
>
Imports System.Data.Sql Client
Imports System.IO
Imports System.Drawing
Imports System.Drawing. Imaging
Imports System.Data.Lin q
>
>
Partial Class showPicture
Inherits System.Web.UI.P age
>
>
Protected Sub Page_Load(ByVal sender As Object, ByVal e As
System.EventArg s) Handles Me.Load
Dim imageID As Integer =
Convert.ToInt32 (Request.QueryS tring("PictureI D"))
>
Dim db As New DataClassesData Context()
>
Dim query As Binary = (From x In db.pictures Where x.ID = imageID
Select x.image).Single ()
>
Dim imgContent As Byte() = query.ToArray()
Response.Conten tType = ("image/jpeg")
>
'set the size of the desired thumbnail in px
Dim thumbWidth As Integer = 200
Dim thumbHeight As Integer = 200
>
Dim s As New MemoryStream(im gContent)
>
>
Dim image1 As New Bitmap(s)
>
Dim bmpOut As System.Drawing. Bitmap
>
Try
Dim bmpIn As New Bitmap(s)
Dim bmpFormat As ImageFormat = bmpIn.RawFormat
Dim calcRatio As Decimal
Dim thumbNewWidth As Integer = 0
Dim thumbNewHeight As Integer = 0
>
If bmpIn.Width bmpIn.Height Then
calcRatio = CDec(thumbWidth ) / bmpIn.Width
thumbNewWidth = thumbWidth
Dim thumbHeightTemp 1 As Decimal = bmpIn.Height * calcRatio
thumbNewHeight = CInt(thumbHeigh tTemp1)
Else
calcRatio = CDec(thumbHeigh t) / bmpIn.Height
thumbNewHeight = thumbHeight
Dim thumbWidthTemp2 As Decimal = bmpIn.Width * calcRatio
thumbNewWidth = CInt(thumbWidth Temp2)
End If
>
bmpOut = New Bitmap(thumbNew Width, thumbNewHeight)
Dim g As Graphics = Graphics.FromIm age(bmpOut)
g.Interpolation Mode =
System.Drawing. Drawing2D.Inter polationMode.Hi ghQualityBicubi c
g.FillRectangle (Brushes.White, 0, 0, thumbNewWidth,
thumbNewHeight)
g.DrawImage(bmp In, 0, 0, thumbNewWidth, thumbNewHeight)
>
bmpIn.Dispose()
Catch
Return
End Try
>
Try
bmpOut.Save(Res ponse.OutputStr eam,
System.Drawing. Imaging.ImageFo rmat.Jpeg)
Catch
Finally
bmpOut.Dispose( )
End Try
End Sub
End Class
>
>
This seems to work!

[=?Utf-8?B?SmFtZXMgUGFnZQ==?=]

Re: LINQ and blobs

Bruce -

Thanks for your reply - I'm trying to standardise a particular website to
utilise LINQ and call everything from classes in the app_code folder. I know
some queries are better using SQL but this particular web app has become
unwieldly and because of a major upgrade it seemed like a good idea!! At the
present code is all over the place and many controls were poorly designed -
not to mention increasing my rather poor knowledge of LINQ in the first place.

[rstrahl]

Re: LINQ and blobs

The quick answer is that blobs translate into byte[], so if you import your
image field you should end up with a byte[] property on your entity.

+++ Rick ---

--

Rick Strahl
West Wind Technologies

https://www.west-wind.com/weblog

"James Page" <JamesPage@disc ussions.microso ft.comwrote in message
news:B243BE27-E880-49B1-A744-680097F57B80@mi crosoft.com...

Hi all another LINQ question!!
>
to retrieve and display sql varbinary images I currently use the following
code:
>
Imports System.Data.Sql Client
Imports System.Drawing
Imports System.Drawing. Imaging
Imports System.IO
>
>
>
Partial Class ShowPicture
Inherits System.Web.UI.P age
>
Protected Sub Page_Load(ByVal sender As Object, ByVal e As
System.EventArg s) Handles Me.Load
Dim PictureID As Integer =
Convert.ToInt32 (Request.QueryS tring("PictureI D"))
>
'Connect to the database and bring back the image contents & MIME
type for the specified picture
Using myConnection As New
SqlConnection(C onfigurationMan ager.Connection Strings("ImageG alleryConnectio nString").Conne ctionString)
>
Const SQL As String = "SELECT [MIMEType], [ImageData] FROM
[Pictures] WHERE [PictureID] = @PictureID"
Dim myCommand As New SqlCommand(SQL, myConnection)
myCommand.Param eters.AddWithVa lue("@PictureID ", PictureID)
>
myConnection.Op en()
>
Dim myReader As SqlDataReader = myCommand.Execu teReader
If myReader.Read Then
Response.Conten tType = myReader("MIMET ype").ToString( )
Response.Binary Write(myReader( "ImageData" ))
>
>
End If
myReader.Close( )
myConnection.Cl ose()
End Using
End Sub
>
>
End Class
>
I'm now trying to use LINQ to replace the sql elements. Can anyone help me
convert the above using LINQ?