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Use Camera as Barcode Reader

Posted By: Syed Shakeer Hussain     Posted Date: July 20, 2010    Points: 2   Category :Others
some important links



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Performance Tuning on DirectShow Camera Application

Windows CE 6.0 supports DirectShow® components to develop a rich camera application. A minimum requirement of the camera application is to show preview, capturing the still images which is stored as a compressed file (JPG) format, capturing/multiplexing the video with or without audio i.e. stored as a compressed file (WMV) format.

Windows CE 6.0 provides sample applications for showing preview, capturing still and video using DirectShow® components. However these sample applications doesn't cover all the aspects to develop a commercial application. A commercial camera application at least satisfies the following performance criteria.

Free BarCode Software

Bar Code Specifications

There are more than 300 different types of barcodes, all with their own specifications. You will find detailed specifications of many popular bar code symbologies and where you can order the official specifications here at BarCode-1.

Barcode-1 Specification Sources Page list the most popular barcodes. It has links to technical information and is a good place to start.
The UPC/EAN Barcode Page lists the details of UPC barcode, and EAN barcode, the type used in grocery stores.
UCC128, EAN128 and GS1-128 Page lists the details for this important standard for marking shipping cartons.
The Code 39 Barcode Page has the details for Code 39 barcode, the most popular barcode used in industrial application.
The Code 128 Barcode Page has the details for Code 128 barcode, a barcode that can encode the entire ASCII character set.
The Interleaved 2 of 5 (I 2 of 5) Barcode Page has the details of this popular barcode.
The NW-7 Barcode Page has the details about this popular barcode in Japan.
The Plessey Code Barcode Page has the details for the historically important barcode.
The 2D Barcode Page lists the most popular two dimensional barcodes. It has links to technical information and is a good place to start if you a looking for 2D barcode information.

The Free Barcode Creator produces barcode images one at a time, and allows easy saving to a file or

The Free Barcode Creator produces barcode images one at a time, and allows easy saving to a file or pasting into an application. 2D versions are also available:

reader.getordinal("column_may_not_exist") how to catch the exception?



would any body please help me to catch the exception if the column doesnot exist as my table columns are not static.

sometimes its throwing me indexoutofrange exception as the column doesnot exist

thanks for the help guys

Concurrent Affairs: Reader/Writer Locks and the ResourceLock Library


If multiple threads concurrently execute code that writes to or modifies a resource, then obviously the resource must be protected with a thread synchronization lock to ensure that the resource doesn't get corrupted.

Jeffrey Richter

MSDN Magazine June 2006

Editor's Note: Reader E-mail


Here at MSDN Magazine, we get a lot of mail from readers. As you can imagine, much of it involves fulsome praise for our content, our eye-catching covers, or the handsome photo that now graces this page.

Joshua Trupin

MSDN Magazine June 2005

Linq2Sql error: "Invalid attempt to call Read when reader is closed."


I've read up on this error from other posts and on other sites, but haven't found a solid resolution to the issue yet. My setup is as follows:

I have a RepositoryBase class that fields certain db calls that all repositories need to perform. In one such call, "GetSecurityGroup", it works most of the time, but will seemingly at random throw an exception with the error "Invalid attempt to call Read when reader is closed." All other Repository classes inherit from this one, and they all use the same DataContext object, which I understand isn't thread safe. Since there could be multiple calls to the DataContext object on the same page, perhaps one is using the DataContext when the next tries to do so. I'm not sure. What can I do to ensure this doesn't happen?

Capturing video remote from specific camera

Hi, I like to capture video with this camera http://www.sparkfun.com/commerce/product_info.php?products_id=8773 it has a rca output wich should be converted to a bytearray to send over a serial interface like ZigBee and back to show it on a eg laptop. I've got two questions: 1. How can I convert a rca signal to a bytearray? 2. How can I convert a bytearray back to a rca signal? Rca is the yellow plug for your video! Any help would be appreciated! Roel

How to stop blurring of barcode images

I have a custom DLL that has a function that takes a string and returns a raster image(PNG) of a Code 128 barcode. That works fine, no problem. The barcode rendered does *not* use a font, it physically renders rectangles with precise pixel widths to generate the barcode. This is necessary because the laser expects a discrete stop of a "bar" and beginning of a "space". -- Image properties->Size is set to "Original Size" So I look at the report viewer, and I see barcodes. Cool. HOWEVER ... when I zoom in at about 400% I start to see blurring at the edges of the bars. It also prints this way. This is unacceptable. So then, within report viewer, (this is the same report!) I export the report to PDF. No blurring, not at 500%, not at 2000% not at any zoom level. In the PDF, there is a sharp, precise, quantum drop from black to white with *no* blurring whatsoever. On pixel is 0x000000 and the next is 0xFFFFFF. The PDF also prints this way. This is correct behavior. I cannot have the user export the report to PDF before printing it. This is a production shop, and I can't have folks taking twice as long to do a task. MY QUESTION: How do I instruct, how do I force SSRS to simply render the image as I have presented it and not tinker with it? This is a bit annoying. If my function returns a 200x50 image, SSRS may trust that that is what is t

How do I determine null with ADO reader?

I am using ADO reader to read rows in a table with matching values in two columns.  But when the reader has rows and one of the columns in a row is null instead of a long number, I get an error when I attempt to access the value.  In C# language, I have a statement that says "if (reader["Example"] != null) ExampleID = (long)reader["Example"];".  Unfortunately, the "if" statement does not detect the null value in the column and it attempts to store null in the "ExampleID" long variable and an error states "Specified cast is not valid.  When casting from a number, the value must be a number less than infinity."  What should I do to prevent accessing a null value?   Maurice

Sending 2D Barcode via SMS

Can any one suggest me the approach to send 2D barcodes via SMS. Am developing a sample application which generated text as 2D barcode. I want to send this as SMS to mobile phones. I dont have any idea to proceed. Is there any API avalible. Please suggest. Regards, Megarekaa.

Data Reader Destination issue

Hi, I'm new to BI, I created a package to test the data reader destination the dtsx is executing well every thing is green but what after that. The question is how to use this Data reader destination? As I know as a .net programmer there  is a class named data reader that could be used to retieve data in connected mode programmatically using a  connection and a command objects, but in the case of data reader destination how to use it. Or am I confusing the data reader that I kno in the ADO .Net with this one used in BIDS  Should I add a script task after the data reader destination or should I consume this data reader within my proper separate code with a dll or an exe that I create as a .Net project ? For instance, two properties are remaquables for me those are locted within the custom proeprties  datareader and  usercomponentdatatype   The complexity resides in the simplicity

Dotnet Library For RFID and BarCode Devices

I have an time and attendance application that takes Employee Id for Employee Attendance.Using such dotnet library i want to read the data(Codes) from rfid codes or bar codes from employee card.so that i may use that data for further processing of my time and attendance application .

Twitter reader

Dear all,I have writing software Twitter reader by C# and reading from this link http://twitter.com/statuses/friends_timeline.xml , in the first time my soft run very good but since Twitter to change system to authentication account then my soft not work.Code twitter reader I used:        client = new WebClient(); client.Credentials = new NetworkCredential(user, pass); stream = client.OpenRead(APILink); reader = new StreamReader(stream); xml_read = new XmlTextReader(reader); xml_Doc = new XmlDocument(); xml_Doc.Load(xml_read); Please help me this problem.Thanks a lot,My email: kieungocdung@hotmail.com

Log Reader Error: The process could not execute 'sp_repldone/sp_replcounters'

I have transactional replication going between servers A and B. SQL Server 2005 64 bit A is Publisher B is Distributor and Subscriber Now I am getting the following Log reader Agent Error Msg The process could not execute 'sp_repldone/sp_replcounters' on 'A'. (Source: MSSQL_REPL, Error number: MSSQL_REPL20011) Get help: http://help/MSSQL_REPL20011 Only one Log Reader Agent or log-related procedure (sp_repldone, sp_replcmds, and sp_replshowcmds) can connect to a database at a time. If you executed a log-related procedure, drop the connection over which the procedure was executed or execute sp_replflush over that connection before starting the Log Reader Agent or executing another log-related procedure. (Source: MSSQLServer, Error number: 18752) Get help: http://help/18752 The process could not set the last distributed transaction. (Source: MSSQL_REPL, Error number: MSSQL_REPL22017) Get help: http://help/MSSQL_REPL22017 The process could not execute 'sp_repldone/sp_replcounters' on 'A'. (Source: MSSQL_REPL, Error number: MSSQL_REPL22037) Get help: http://help/MSSQL_REPL22037 Can anybody help me in solving this issue? I read that we have to delete the existing publication and subscription.  Is there any way to solve this problem without deleting the existing subscription and publication Any help would be appreciated Thanks

Creating Barcode Image

Hello Guys.Posted a question earlier but i havent recieved a reply. i wanted to create a barcode using vbscript or javascripting. Dont know if this makes a difference which one i use  The barcode will be linked to information stored in my access database. The barcode will be displayed on a webpage, so for this i'm using Dreamweaver CS4. I have to 2 barcode fonts available and DLL file they are:FRE3OF9X.TTFi2of5txt.ttfBarcode.dll (not sure i need this)I prefer to use the interleaved 2of5 font. I have no experience of coding in general Vbscript or asp.net. From this situation how would i go about creating a barcode image.All feedback welcome. Thank you very much...
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