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.
same day cleaning service Des Plaines ..Tip #1. Do a Google search. Don't be to general... Read More
Most of the web applications have a lot of images... Read More
I have a p3 500MHz PC with 128MB RAM, 10.2... Read More
Digital Video Disc or as it is sometimes referred to... Read More
MP3 players are everywhere! It seems that the number of... Read More
As the web has evolved, so have the methods of... Read More
Feeling overwhelmed in selecting a new TV? With all the... Read More
CCNA FAQQ. What exams do I have to take to... Read More
The technological horizon has always got something new to offer,... Read More
Your first step in removing dangerous infections from your computer... Read More
Microsoft Business Solutions is on the way to popularize it's... Read More
Spyware is the software that collects information about your online... Read More
Feeling overwhelmed in selecting a new TV? With all the... Read More
You will need the following:1. 1.44MB FDD (floppy)2. NVFLASH utility... Read More
Maintaining your computer is extremely important ? especially if you... Read More
All over the world, people carry with them walkmans and... Read More
Using SQL Server 2000 and above versions you can retrieve... Read More
ComputersBusinesses and individuals alike have all grown to rely on... Read More
Not so many years ago, homes across the country watched... Read More
Music lovers have been carrying around radios and other bulky... Read More
One of the most confusing parts of beginning your Cisco... Read More
Everywhere you look today people are listening to personal audio... Read More
As the Web grows more crowded and just plain "noisy"... Read More
What is a Refurbished Computer?Refurbished Computers. Remanufactured Computers. Reconditioned Computers.... Read More
Cisco Certification: Taking Your First Certification ExamYou've studied hard; you've... Read More
home cleaning services Mundelein ..It's free, it comes with Windows and it's used by... Read More
In the 1950's and 1960's Polaroid's instant cameras were all... Read More
Are you looking for an MP3 player but am not... Read More
Microsoft Certifications are one of the most widely acclaimed, pursued,... Read More
Yes, it's true. You may have inadvertently invited a spy... Read More
Each of the items in the checklist below is part... Read More
I would like to tell you about a magic home.... Read More
1. Before sitting down for coding, you must have formal... Read More
There are many sources of heat that can raise the... Read More
Many computer users are worried about their computer's performance. After... Read More
In Windows Xp, you can install two operating systems on... Read More
Millions have enjoyed recorded music since 1877 when Thomas Edison... Read More
If you don't have an mp3 player, and even if... Read More
Do you remember the old saw about how computers would... Read More
There are plenty of articles out there about how to... Read More
Although there are many things that can affect the performance... Read More
Selecting a TV isn't as easy as it used to... Read More
Having two operating systems is not as difficult as many... Read More
Webmasters usually sit at their computers much longer in a... Read More
MP3 players are Hot! Playing music has come a long... Read More
1. Empty the Temp directory regularly. To do this, make... Read More
Feeling overwhelmed in selecting a new TV? With all the... Read More
Your Bible At Your FingertipsIt is fairly easy to find... Read More
The Internet can be a dangerous place.While you're enjoying the... Read More
Tech support tells me to type 'regedt32' as opposed to... Read More
Personal Technology |