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.
premium house cleaning Wilmette ..By using your computer today you can find a lot... Read More
Viruses, software failures, power failures, human errors, hard drive failures... Read More
Upgrading your processor will always speed up your computer, but... Read More
I have always been interested in computers, but in the... Read More
Step 1:Open WinRAR and browse to the folder with your... Read More
HTTP ProtocolThe web is run on port 80. You are... Read More
IntroductionMac OS X is the most technologically advanced operating system... Read More
Time is money. And when you constantly have to divide... Read More
Cookies, not the kind that Mom makes, but the computer... Read More
Stop Getting LostOne of the greatest uses for a pocket... Read More
Saving Lives With A Pocket PCFree medical downloads can be... Read More
BIOS - Basic Input Output SystemThe central processing unit of... Read More
The Cisco Certified Network Associate (CCNA) Certification is meant for... Read More
One of the most confusing parts of beginning your Cisco... Read More
When I first started studying for my CCNP, some of... Read More
Google, in their march to stay ahead of the pack... Read More
"Automated Testing" is automating the manual testing process currently in... Read More
You probably heard of the new Firefox browser version 1.0... Read More
After another security hole recently surfaced in Microsoft's Windows operating... Read More
Want to save money while promoting your web-based business? Of... Read More
Are you thinking of buying an Apple iPod? Or have... Read More
For six years, my Samsung PC 13.8 inch SyncMaster conventional... Read More
So you've got some spyware, ad-ware, or viruses on your... Read More
Microsoft Business Solutions is on the way to popularize it's... Read More
Computers are supposed to speed up our productivity?to help us... Read More
personalized cleaning services Deerfield ..Viruses, software failures, power failures, human errors, hard drive failures... Read More
IntroductionMac OS X is the most technologically advanced operating system... Read More
Enhanced Definition Television ? also known as EDTV ? is... Read More
Using SQL Server 2000 and above versions you can retrieve... Read More
Feeling overwhelmed in selecting a new TV? With all the... Read More
HTTP ProtocolThe web is run on port 80. You are... Read More
Below you will find some useful information and comments about... Read More
The technological horizon has always got something new to offer,... Read More
What is a Refurbished Computer?Refurbished Computers. Remanufactured Computers. Reconditioned Computers.... Read More
The following practice, if done regularly, may help you to... Read More
First things first, what is Firefox? Well, it's a browser.... Read More
Wouldn't you be shocked to find that your personal sensitive... Read More
I got my eyes set on a iPod mini, as... Read More
Not so many years ago, homes across the country watched... Read More
After reading this good article you will know some important... Read More
Plenty! When we made the decision to be our own... Read More
When studying for your Cisco CCNA, CCNP, or CCIE exam,... Read More
Google, in their march to stay ahead of the pack... Read More
Computers are everywhere, and vary in specification, brands, sizes, shaped,... Read More
Buying Your PCBuying a PC that's right for you and... Read More
Save money. Save 10-15% on utility bills per month. Work... Read More
Cameras: still known for taking pictures but assumed as digital... Read More
Your Bible At Your FingertipsIt is fairly easy to find... Read More
Good Morning Mr. Sampson. Please type in you Personal Identification... Read More
I have a p3 500MHz PC with 128MB RAM, 10.2... Read More
Personal Technology |