Recently, I developed an E-Commerce site, a mobile phone shopping mall, where pages and its contents are created dynamically when the customer selects his/ her preferred mobile phone. The image of the phone and logo of the phone vendor are stored in the database as BLOB. I wanted to read this BLOB and display it on customer request. I created a sample application, for reading the BLOB and displaying it, to demonstrate this.
I use the pubs database for this example, which is created when SQL Server is installed. I populate the publication IDs from the pub_info table to a dropdown list, and when the selection is done, the appropriate logo will be displayed.
Using the code
Create a separate aspx file to hold the image. An aspx file for holding the image? Are you kidding? Wait, look what is happening. Create a method in the code-behind file of the aspx page to read a BLOB value.
CreateImage(string id) is the method that reads the BLOB. The
string id parameter gets the image ID that the user selects from the drop down list. To read the BLOB value, use the
ExecuteScalar() method of the
ExecuteScalar() returns an
object, so we should cast it and store in a
byte array like this.
byte _buf = (byte) _cmd.ExecuteScalar();
Then, stream it back to the HTTP response. The complete code is shown below:
void CreateImage(string id)
SqlConnection _con = new SqlConnection(
SqlCommand _cmd = _con.CreateCommand();
_cmd.CommandText = "select logo from" +
" pub_info where pub_id='" +
id + "'";
byte _buf = (byte)_cmd.ExecuteScalar();
Response.ContentType = "image/gif";
private void Page_Load(object sender, System.EventArgs e)
The page retrieves the image ID using a query string. Now, I'm going to display the image. In order to display the image, use a
HtmlServerControl where you want. Set its
src property like this.
<img src='<%# "imgs.aspx?id=" + drpIds.SelectedValue %>'>
To evaluate this magical data binding formula, we should call:
in the drop down list's
That's all. Run the application and enjoy it.
I’ve started my career in 2001 with Microsoft .net ver 1.0. I’m a MCSD for .net.
Currently, I’m working for Sri Lanka’s largest apparel exporter as a Software Engineer. All projects in .net, MS Sql Server, Biztalk Server, WCF and WPF. And also, I’m developing components to the ERP. In addition to that, I’ve involved to create architecture of ERP integration.