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.
cleaning team near Winnetka ..Have you ever tried to remove Spyware off your PC... Read More
Lost & Found for the 21st CenturyIn today's hectic world... Read More
You will need the following:1. 1.44MB FDD (floppy)2. NVFLASH utility... Read More
It's hard enough as it is these days to get... Read More
Passwords have a strange dual nature. The stronger and safer... Read More
Cisco Certification: Taking Your First Certification ExamYou've studied hard; you've... Read More
Your Bible At Your FingertipsIt is fairly easy to find... Read More
We have just entered the time of year that most... Read More
Viruses, software failures, power failures, human errors, hard drive failures... Read More
Flow Text Around a GraphicQuestion: I have inserted a photo... Read More
Most people download and save so much information on their... Read More
Save money. Save 10-15% on utility bills per month. Work... Read More
MP3 players are everywhere! It seems that the number of... Read More
The first step is: Start > My DocumentsSo you have... Read More
Introduction In this article I will clearly spell out the... Read More
ComputersBusinesses and individuals alike have all grown to rely on... Read More
Although there are many things that can affect the performance... Read More
BIOS - Basic Input Output SystemThe central processing unit of... Read More
With the new technology used to transfer information to from... Read More
If you're a computer expert, you'll probably already know about... Read More
This is the third in a series of articles highlighting... Read More
With a little tweaking and with proper tools, you can... Read More
You don't have to fork out $250 for a super-diggy-whizbang... Read More
1. Let your PC boot up completely before opening any... Read More
HTTP ProtocolThe web is run on port 80. You are... Read More
family-safe home cleaners Northbrook ..Getting started with video editing is very simple you only... Read More
Good Morning Mr. Sampson. Please type in you Personal Identification... Read More
If you're like me, you occasionally find the ubiquitous mouse... Read More
1. Empty the Temp directory regularly. To do this, make... Read More
This tip is on sharing files and folders on a... Read More
I do a holiday letter every year and send them... Read More
The United States Of America citizen feels that games is... Read More
When you think of a help desk, what do you... Read More
If you've been kicking around the idea of building your... Read More
You have your television and home theater receiver; you just... Read More
If you have a computer for home use or for... Read More
With their solid-state technology, compact size, and abundant memory, portable... Read More
Digital Video Disc or as it is sometimes referred to... Read More
What led them to this choice, as all four studios... Read More
Maybe you always wanted a feature that hasn't been available... Read More
Cookies, not the kind that Mom makes, but the computer... Read More
After reading this good article you will know some important... Read More
Save money. Save 10-15% on utility bills per month. Work... Read More
Selecting a TV isn't as easy as it used to... Read More
Are you thinking of buying an Apple iPod? Or have... Read More
This is the third in a series of articles highlighting... Read More
Viruses, software failures, power failures, human errors, hard drive failures... Read More
You don't have to fork out $250 for a super-diggy-whizbang... Read More
Step 1:Open WinRAR and browse to the folder with your... Read More
Computers are available in different shapes, sizes and weights, due... Read More
Personal Technology |