Tech or Treat! Write an article about your scariest tech disaster to win gadgets!Learn more

x
?
Solved

Transferring Image DataType between Two Databases

Posted on 2006-10-30
6
Medium Priority
?
262 Views
Last Modified: 2010-04-16
I am writing a comms application that transfers data from a main PC application to a mobile device (using SQL Mobile) and the only datatype I'm having trouble transferring is Image.

I'm using the ExecuteReader method of the SqlCommand object, and then using GetValues() of the DataReader to populate an array with the database values.

i.e.

reader.GetValues(argArray);

The argArray now contains the value of an image field from the main PC app, but I am unsure of how to convert this value back to a suitable format to use in a SQL Statement for the mobile database.

Essentially, I'm looking for a way to convert a value (of type Object) into a format that conforms to the SQL Server IMAGE datatype.

Can anyone help me with this?
0
Comment
Question by:AMLabels
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 3
6 Comments
 
LVL 48

Expert Comment

by:AlexFM
ID: 17832705
http://www.codeproject.com/cs/database/albumviewer.asp

This sample shows how to convert image file to SQL database field, and how to read image from database and save to file. You can remove file handling and use read and write code fragments for your task.
0
 

Author Comment

by:AMLabels
ID: 17832812
Without using the FileStreams, how can I convert the Object instance to a byte[]?

This code raises an InvalidCastException on the second line:

Object obj = argsArray[index];
byte[] img = (byte[])obj;

Thanks.
0
 
LVL 48

Accepted Solution

by:
AlexFM earned 1500 total points
ID: 17832844
This is code fragment from the function which reads image from database:

        string strCmd = String.Format("SELECT photo FROM Photos WHERE id = {0}",
                                      item.Id);
        SqlCommand cmd = new SqlCommand(strCmd, sqlConn);
                       
        // Set the description
        lblDesc.Text = item.Desc;

        // Get bytes return from stored proc
        byte[] b = (byte[])cmd.ExecuteScalar();

Now you can call function InsertImage which requires byte[] parameter. Pass b to it, and image is copied from one database to another.
0
Concerto's Cloud Advisory Services

Want to avoid the missteps to gaining all the benefits of the cloud? Learn more about the different assessment options from our Cloud Advisory team.

 

Author Comment

by:AMLabels
ID: 17833874
This works, except that the SQL parameter for images must be formatted as Hex, not base 2.

Does the .NET Framework provide the functionality to convert a byte array into a Hex string?
0
 

Author Comment

by:AMLabels
ID: 17833959
Whoops, made a mistake there. I meant to say the format of the image in SQL Statements needs to be Hex and not Base 10.
0
 
LVL 48

Expert Comment

by:AlexFM
ID: 17833973
How does CodeProject sample work without this conversion?
There is poorly documented XmlConvert.ToBinHexString method which possibly does this. I understand that such conversion is required for XML files, but why does SQL need this? Please check again, I think this should work directly.
0

Featured Post

VIDEO: THE CONCERTO CLOUD FOR HEALTHCARE

Modern healthcare requires a modern cloud. View this brief video to understand how the Concerto Cloud for Healthcare can help your organization.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Entity Framework is a powerful tool to help you interact with the DataBase but still doesn't help much when we have a Stored Procedure that returns more than one resultset. The solution takes some of out-of-the-box thinking; read on!
Exception Handling is in the core of any application that is able to dignify its name. In this article, I'll guide you through the process of writing a DRY (Don't Repeat Yourself) Exception Handling mechanism, using Aspect Oriented Programming.
Add bar graphs to Access queries using Unicode block characters. Graphs appear on every record in the color you want. Give life to numbers. Hopes this gives you ideas on visualizing your data in new ways ~ Create a calculated field in a query: …
Please read the paragraph below before following the instructions in the video — there are important caveats in the paragraph that I did not mention in the video. If your PaperPort 12 or PaperPort 14 is failing to start, or crashing, or hanging, …

647 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question