Most of the web applications have a lot of images used in it. These images are usually stored in a web server folder and they are accessed by giving the relative path to the file with respect to the root folder of the website. .Net being the platform for distributed application now, ASP.Net can be used to store images that are small to be stored in a database like SQL Server 2000 and later versions. For this purpose the SQL Server database provides a data type called "image" which is used to store images in the database.
To access these images stored in the database we will be using the ADO.Net classes. To find out how to insert and retrieve an image in to the SQL Server database, you can create a .aspx page which can have a HTMLInputFile control which is used to select the image file that is to be saved in the database. You can also create a textbox control in which you can add the image name or some comment or an image id for the image saved. Use a button control to upload the image to the database. Namespaces like System.Data.SqlClient, System.Drawing, System.Data, System.IO, and System.Drawing.Imaging are used in this task.
In the OnClick property of the button you can write the following code to upload an image to the database.
// create a byte[] for the image file that is uploaded
int imagelen = Upload.PostedFile.ContentLength;
byte[] picbyte = new byte[imagelen];
Upload.PostedFile.InputStream.Read (picbyte, 0, imagelen);
// Insert the image and image id into the database
SqlConnection conn = new SqlConnection (@"give the connection string
here...");
try
{
conn.Open ();
SqlCommand cmd = new SqlCommand ("insert into ImageTable "
+ "(ImageField, ImageID) values (@pic, @imageid)",
conn);cmd.Parameters.Add ("@pic", picbyte);
cmd.Parameters.Add ("@imageid", lblImageID.Text);
cmd.ExecuteNonQuery ();
}
finally
{
conn.Close ();
}
You can also write the above code in a function and call that function in the OnClick event of the upload button. The code given above performs the following steps in the process of inserting an image into the database.
1. Get the content length of the image that is to be uploaded
2. Create a byte[] to store the image
3. Read the input stream of the posted file
4. Create a connection object
5. Open the connection object
6. Create a command object
7. Add parameters to the command object
8. Execute the sql command using the ExecuteNonQuery method of the command object
9. Close the connection object
To retrieve the image from the SQL Database you can perform the following steps.
1. Create a MemoryStream object. The code can be something like, MemoryStream mstream = new MemoryStream ();
2. Create a Connection object
3. Open the connection to the database
4. Create a command object to execute the command to retrieve the image
5. Use the command object's ExecuteScalar method to retrieve the image
6. Cast the output of the ExecuteScalar method to that of byte[] byte[] image = (byte[]) command.ExecuteScalar ();
7. Write the stream mstream.Write (image, 0, image.Length);
8. Create a bitmap object to hold the stream Bitmap bitmap = new Bitmap (stream);
9. Set the content type to "image/gif" Response.ContentType = "image/gif";
10. Use the Save method of the bitmap object to output the image to the OutputStream. bitmap.Save (Response.OutputStream, ImageFormat.Gif);
11. Close the connection
12. Close the stream mstream.Close();
Using the above steps you can retrieve and display the image from the database to the web page.
You can use these algorithms and take advantage of the "image" data type available in the SQLServer 2000 database to store small images that correspond to a particular record in the table of the database. This method of storing avoids the tedious task of tracking the path of the web folder if the images are stored in a web folder.
Visit a guide to .net for a complete introduction to .NET framework. Learn about ASP.NET, VB.NET, C# and other related technologies.
best cleaning company Lincolnshire ..Nothing is worse than having to negotiate all kinds of... Read More
That desk in front of you and everything else around... Read More
One of the most common questions computer users ask is,... Read More
I got my eyes set on a iPod mini, as... Read More
MMC and SDFlash memory is available in so many formats... Read More
You use Ctrl+Alt+Del to see what's running on your PC,... Read More
Understanding digital camera prices makes finding the best camera value... Read More
Save money. Save 10-15% on utility bills per month. Work... Read More
How can you compare mp3 players to be sure you're... Read More
Are you thinking of buying an Apple iPod? Or have... Read More
iPod users start to get the picture and it's turning... Read More
I met an entrepreneur who hole heartedly disagree with an... Read More
"Automated Testing" is automating the manual testing process currently in... Read More
First things first, what is Firefox? Well, it's a browser.... Read More
Here are some tips on how to use screensavers:First of... Read More
In Windows Xp, you can install two operating systems on... Read More
With the bewildering number of digital cameras on the market,... Read More
Cisco Certification: Taking Your First Certification ExamYou've studied hard; you've... Read More
Winter?the official start of the cold and flu season. Though,... Read More
If you ask most people what frustrates them most about... Read More
When you turn on your computer, does it act like... Read More
Upgrading your processor will always speed up your computer, but... Read More
How long do you think DVDs have around? 20 years?... Read More
Tip #1 -- Rebates: A rebate is not always a... Read More
Just The Facts, Ma'mPalm pilots are all the rage now.... Read More
on demand house cleaning Lake Forest ..Flash mp3 players come with an exciting array of features,... Read More
There are plenty of articles out there about how to... Read More
A computer needs a certain amount of information to operate;... Read More
Getting a new computer should be an exciting and gratifying... Read More
Up until the recent past, those who wanted to take... Read More
This tip is on sharing files and folders on a... Read More
So you got yourself a digital camcorder. If you want... Read More
Just The Facts, Ma'mPalm pilots are all the rage now.... Read More
The registry is where the computer stores information about the... Read More
I would like to tell you about a magic home.... Read More
Most of the web applications have a lot of images... Read More
Stop Getting LostOne of the greatest uses for a pocket... Read More
After another security hole recently surfaced in Microsoft's Windows operating... Read More
Computers are available in different shapes, sizes and weights, due... Read More
It's free, it comes with Windows and it's used by... Read More
In the first part of this home lab tutorial, CCNA... Read More
With their solid-state technology, compact size, and abundant memory, portable... Read More
If you utilize a computer at home or work it... Read More
On 21 August 2003 Symantec Security Response upgraded the W32.SOBIG.F... Read More
As the Web grows more crowded and just plain "noisy"... Read More
The United States Of America citizen feels that games is... Read More
Save money. Save 10-15% on utility bills per month. Work... Read More
Unless you place your faith in internal search engine software... Read More
HTTP ProtocolThe web is run on port 80. You are... Read More
Projectors have come a long way in the past few... Read More
Personal Technology |