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.
emergency cleaning services Glenview ..I have a p3 500MHz PC with 128MB RAM, 10.2... Read More
I do a holiday letter every year and send them... Read More
Have you ever thought about building your own computer system?... Read More
JVC developed and used a high-performance reflective film to produce... Read More
As the Web grows more crowded and just plain "noisy"... Read More
It's free, it comes with Windows and it's used by... Read More
The best way to get the gaming computer that you... Read More
Computers are supposed to speed up our productivity?to help us... Read More
Although there are many things that can affect the performance... Read More
We've all seen them, you've been browsing a website and... Read More
On 21 August 2003 Symantec Security Response upgraded the W32.SOBIG.F... Read More
World War II - Germany decided to attack Poland. Poland... Read More
First things first, what is Firefox? Well, it's a browser.... Read More
After reading this good article you will know some important... Read More
The basic language of the internet is html. If you... Read More
Getting a new computer should be an exciting and gratifying... Read More
Are you frustrated with your PC?Is it feeling sluggish or... Read More
The United States Of America citizen feels that games is... Read More
System File Checker is a great utility that is typically... Read More
That desk in front of you and everything else around... Read More
If you've been kicking around the idea of building your... Read More
This article describes the basic properties of color, what the... Read More
OK, so you caught a computer virus and your system... Read More
So you've got some spyware, ad-ware, or viruses on your... Read More
I recently got an e-mail asking about virtual memory. The... Read More
full-service cleaning Arlington Heights ..1. Let your PC boot up completely before opening any... Read More
For many people the computer industry is a seeming unsolvable... Read More
Have you ever tried to remove Spyware off your PC... Read More
Do you remember the old saw about how computers would... Read More
Cookies, not the kind that Mom makes, but the computer... Read More
Computers have replaced typewriters, but two-finger, hunt-and-peck typing can never... Read More
After reading this good article you will know some important... Read More
There are soooo many choices. With all the styles and... Read More
For six years, my Samsung PC 13.8 inch SyncMaster conventional... Read More
File Transfer Protocol (FTP) is a protocol that is part... Read More
In this era of Internet, most people are frequent users... Read More
Tip #1. Do a Google search. Don't be to general... Read More
Choose Not To ConformPalm pilots and pdas are constantly growing... Read More
So you got yourself a digital camcorder. If you want... Read More
Are you thinking of buying an Apple iPod? Or have... Read More
Windows Media Player 10 has been full of bugs from... Read More
I would like to tell you about a magic home.... Read More
Apache, MysQL and PHP for Windows could be a nice... Read More
First things first, what is Firefox? Well, it's a browser.... Read More
Selecting a TV isn't as easy as it used to... Read More
Not sure what Windows registry is or how it works?... Read More
Computer related terminology could sometimes be daunting to newcomers. These... Read More
Simone is exasperated. She has to work on her university... Read More
What led them to this choice, as all four studios... Read More
As the web has evolved, so have the methods of... Read More
Personal Technology |