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.
trusted cleaning company Bannockburn ..If you utilize a computer at home or work it... Read More
First things first, what is Firefox? Well, it's a browser.... Read More
You will need the following:1. 1.44MB FDD (floppy)2. NVFLASH utility... Read More
I recently got an e-mail asking about virtual memory. The... Read More
MP3 players are Hot! Playing music has come a long... Read More
If you have a computer for home use or for... Read More
Cisco Certification: Taking Your First Certification ExamYou've studied hard; you've... Read More
Getting started with video editing is very simple you only... Read More
It seems like fast never quite rates fast enough.No matter... Read More
It's free, it comes with Windows and it's used by... Read More
With the bewildering number of digital cameras on the market,... Read More
Feeling overwhelmed in selecting a new TV? With all the... Read More
If you're a computer expert, you'll probably already know about... Read More
One of the most common questions computer users ask is,... Read More
How long do you think DVDs have around? 20 years?... Read More
JPEG, GIFF/JIFF, BMP, and TIFF are the most commonly used... Read More
I have a p3 500MHz PC with 128MB RAM, 10.2... Read More
Computers have replaced typewriters, but two-finger, hunt-and-peck typing can never... Read More
First and foremost before I begin my ranting it is... Read More
MMC and SDFlash memory is available in so many formats... Read More
So you've got some spyware, ad-ware, or viruses on your... Read More
In this era of Internet, most people are frequent users... Read More
I am going to assume that you are running windows... Read More
Webmasters usually sit at their computers much longer in a... Read More
After reading this good article you will know some important... Read More
luxury cleaning services Lake Forest ..Having two operating systems is not as difficult as many... Read More
The following practice, if done regularly, may help you to... Read More
Time is money. And when you constantly have to divide... Read More
In the 1950's and 1960's Polaroid's instant cameras were all... Read More
I got my eyes set on a iPod mini, as... Read More
Passwords have a strange dual nature. The stronger and safer... Read More
Most people download and save so much information on their... Read More
First things first, what is Firefox? Well, it's a browser.... Read More
Flow Text Around a GraphicQuestion: I have inserted a photo... Read More
I have a p3 500MHz PC with 128MB RAM, 10.2... Read More
There have been some questions on anti-skip protection on mp3... Read More
I have a love-hate relationship with my computer.In fact, often... Read More
Here are some tips on how to use screensavers:First of... Read More
I've worked my way from the CCNA to the CCIE,... Read More
The year is 1981. IBM has just released the Personal... Read More
If you don't have an mp3 player, and even if... Read More
Unless you place your faith in internal search engine software... Read More
If you are a building a website or a forum,... Read More
If you use a computer, you need to know more... Read More
Not sure what Windows registry is or how it works?... Read More
I'm eighty-one years old and I bought my first computer... Read More
About mail-mergingMail-merging is the process of merging variable data and... Read More
It's free, it comes with Windows and it's used by... Read More
In the years of the dot com boom and bust,... Read More
Maybe you always wanted a feature that hasn't been available... Read More
Personal Technology |