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.
kitchen deep cleaning Deerfield ..Ad Blocking is getting to be a common sport on... Read More
ComputersBusinesses and individuals alike have all grown to rely on... Read More
By using your computer today you can find a lot... Read More
The technological horizon has always got something new to offer,... Read More
One of the most common questions computer users ask is,... Read More
Maybe you always wanted a feature that hasn't been available... Read More
Viruses, software failures, power failures, human errors, hard drive failures... Read More
1. Let your PC boot up completely before opening any... Read More
Flash mp3 players come with an exciting array of features,... Read More
Has This Ever Happened To You? OK.. it's Friday night,... Read More
With the new technology used to transfer information to from... Read More
World War II - Germany decided to attack Poland. Poland... Read More
Your Bible At Your FingertipsIt is fairly easy to find... Read More
OK, so you caught a computer virus and your system... Read More
Not so many years ago, homes across the country watched... Read More
Computers are supposed to speed up our productivity?to help us... Read More
A computer needs a certain amount of information to operate;... Read More
MP3 players are everywhere! It seems that the number of... Read More
I met an entrepreneur who hole heartedly disagree with an... Read More
I have always been interested in computers, but in the... Read More
The following practice, if done regularly, may help you to... Read More
Music lovers have been carrying around radios and other bulky... Read More
About mail-mergingMail-merging is the process of merging variable data and... Read More
If you have a computer for home use or for... Read More
Buying a receiver is one of the most important decisions... Read More
interior house cleaning Highland Park ..Flow Text Around a GraphicQuestion: I have inserted a photo... Read More
Since the DOS days, batch files have been one of... Read More
Here are some tips on how to use screensavers:First of... Read More
Cameras: still known for taking pictures but assumed as digital... Read More
I recently took a good look at what was keeping... Read More
File permissions are one of the strengths that the Unix... Read More
If you don't have an mp3 player, and even if... Read More
IntroductionMac OS X is the most technologically advanced operating system... Read More
I am going to assume that you are running windows... Read More
Tech support tells me to type 'regedt32' as opposed to... Read More
All of us are familiar with the pyramids of Egypt.... Read More
If you have a computer for home use or for... Read More
Are you looking for an MP3 player but am not... Read More
The Internet can be a dangerous place.While you're enjoying the... Read More
This is not your typical lost data story. I was... Read More
One of the most confusing parts of beginning your Cisco... Read More
Are you thinking of buying an Apple iPod? Or have... Read More
The best way to get the gaming computer that you... Read More
I do a holiday letter every year and send them... Read More
The battle is heating up for market share, home movie... Read More
How can you compare mp3 players to be sure you're... Read More
Using SQL Server 2000 and above versions you can retrieve... Read More
Windows Media Player 10 has been full of bugs from... Read More
If you're a computer expert, you'll probably already know about... Read More
Choose Not To ConformPalm pilots and pdas are constantly growing... Read More
Personal Technology |