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.
last minute cleaning help Arlington Heights ..It seems like fast never quite rates fast enough.No matter... Read More
If you're like me, you occasionally find the ubiquitous mouse... Read More
Tip #1. Do a Google search. Don't be to general... Read More
If you utilize a computer at home or work it... Read More
When you think of a help desk, what do you... Read More
Has This Ever Happened To You? OK.. it's Friday night,... Read More
Although there are many things that can affect the performance... Read More
Are you frustrated with your PC?Is it feeling sluggish or... Read More
IntroductionMac OS X is the most technologically advanced operating system... Read More
There are plenty of articles out there about how to... Read More
So I'll start from the very beginning.One day I was... Read More
Tech support tells me to type 'regedt32' as opposed to... Read More
You don't have to fork out $250 for a super-diggy-whizbang... Read More
You have your television and home theater receiver; you just... Read More
I am going to assume that you are running windows... Read More
Getting a new computer should be an exciting and gratifying... Read More
I met an entrepreneur who hole heartedly disagree with an... Read More
Simone is exasperated. She has to work on her university... Read More
iPod users start to get the picture and it's turning... Read More
Not sure what Windows registry is or how it works?... Read More
CCNA FAQQ. What exams do I have to take to... Read More
JPEG, GIFF/JIFF, BMP, and TIFF are the most commonly used... Read More
Here are some tips on how to use screensavers:First of... Read More
Since the DOS days, batch files have been one of... Read More
ASR (Automated System Recovery) is a feature available on the... Read More
same day cleaning service Wilmette ..Many computer users are worried about their computer's performance. After... Read More
It seems like fast never quite rates fast enough.No matter... Read More
Unless you place your faith in internal search engine software... Read More
Feeling overwhelmed in selecting a new TV? With all the... Read More
If you've been kicking around the idea of building your... Read More
Yes, it's true. You may have inadvertently invited a spy... Read More
I have a love-hate relationship with my computer.In fact, often... Read More
It's free, it comes with Windows and it's used by... Read More
OK, so you caught a computer virus and your system... Read More
For six years, my Samsung PC 13.8 inch SyncMaster conventional... Read More
ASR (Automated System Recovery) is a feature available on the... Read More
JPEG, GIFF/JIFF, BMP, and TIFF are the most commonly used... Read More
1. Before sitting down for coding, you must have formal... Read More
The Internet is an awesome tool, but be careful and... Read More
Using SQL Server 2000 and above versions you can retrieve... Read More
As the Web grows more crowded and just plain "noisy"... Read More
Flow Text Around a GraphicQuestion: I have inserted a photo... Read More
In the first part of this home lab tutorial, CCNA... Read More
While most small businesses really do need to find a... Read More
Passwords have a strange dual nature. The stronger and safer... Read More
You probably heard of the new Firefox browser version 1.0... Read More
If you're like me, you occasionally find the ubiquitous mouse... Read More
Has This Ever Happened To You? OK.. it's Friday night,... Read More
Up until the recent past, those who wanted to take... Read More
So you've got some spyware, ad-ware, or viruses on your... Read More
Personal Technology |