difference Methods GET and POST in HTML forms

The fundamental differences between "GET" and "POST"

The HTML specifications technically define the difference between "GET" and "POST" so that former means that form data is to be encoded (by a browser) into a URL while the latter means that the form data is to appear within a message body. But the specifications also give the usage recommendation that the "GET" method should be used when the form processing is "idempotent", and in those cases only. As a simplification, we might say that "GET" is basically for just getting (retrieving) data whereas "POST" may involve anything, like storing or updating data, or ordering a product, or sending E-mail.

Differences in server-side processing

In principle, processing of a submitted form data depends on whether it is sent with METHOD="GET" or METHOD="POST". Since the data is encoded in different ways, different decoding mechanisms are needed. Thus, generally speaking, changing the METHOD may necessitate a change in the script which processes the submission. For example, when using the CGI interface, the script receives the data in an environment variable when METHOD="GET" is used but in the standard input stream (stdin) when METHOD="POST" is used.

It is, however, possible to construct libraries of subroutines (e.g. Perl functions) which allow one to write scripts in a manner which works both for METHOD="GET" and METHOD="POST". This would be based on distinguishing between the cases within the subroutine code and returning the data to the caller in a uniform manner.

Possible reasons to use "POST" for idempotent queries

For reasons explained above, one should normally use METHOD="POST" if and only if the form submission may cause changes. There are some exceptional situations where one may consider using METHOD="POST" even for pure queries, too:

• If the form data would contain non-ASCII characters, then METHOD="GET" is inapplicable in principle, although it may work in practice (mainly for ISO Latin 1 characters). Thus, for a query where the keywords might contain e.g. accented letters, you have to select among two evils: using METHOD="GET" against the rules which restrict the character reportoire to ASCII within it, or using METHOD="POST" against the rules which says that it should not be used when the processing is idempotent. The latter alternative is probably less dangerous.
• If the form data set is large - say, hundreds of characters - then METHOD="GET" may cause practical problems with implementations which cannot handle that long URLs. Such usage is mentioned in the the HTML 2.0 specification in an informative note as follows:

  Note - The URL encoding may result in very long URIs, which cause some historical HTTP server implementations to exhibit defective behavior. As a result, some HTML forms are written using METHOD=POST even though the form submission has no side-effects.

• You might wish to avoid METHOD="GET" in order to make it less visible to users how the form works, especially in order to make "hidden" fields (INPUT TYPE="HIDDEN") more hidden. Using POST implies that users won't see the form data in the URL shown by the user; but note that this is not a very effective method of hiding, since the user can of course view the source code of your FORM element!

Partial Classes in ASP.NET

Partial class is a new functionality that is included in Visual Studio .Net 2005 and is supported in ASP.Net 2.0. This new functionality helps you to split a single class into multiple partial classes. These partial classes can be in different individual files.

In the previous versions of the Visual Studio .Net IDE, when you create a new ASP.Net webform, the name of the web form is used as a class in the code-behind file. Apart from that, you would have seen lots of code generated by Visual Studio .Net itself. In the latest version of the Visual Studio .Net IDE, the codes that are generated by Visual Studio .Net are in a separate file as a partial class. Hence a user who creates a new webform would see a partial class for that page, when the user uses the code-behind file. This way the code that is seen in the code-behind file is minimal for a particular webform.
The code given below gives the implementation of the partial classes.
'-----File_1.vb
Imports System
Interface IPartialClass
Sub PrintEmployeeName(ByVal sName As String)
Sub PrintEmployeeName()
End Interface
Partial Class MyPartialClass
Private sName As String = "sName Variable - John Peter - From Partial Class."
End Class
'-----File_2.vb
Imports System
Partial Public Class MyPartialClass
Implements IPartialClass
Public Sub PrintEmployeeName(string str)
Response.Write(str)
End Sub
End Class
'-----File_3.vb
Imports System
Partial Public Class MyPartialClass
Public Sub PrintEmployeeName()
Response.Write(sName)
End Sub
End Class
if you are writing your code for partial classes in C#, it is necessary for all the classes to have the ‘partial’ keyword. This is a significant difference between VB.Net and C# in using partial classes
Since we are dealing with different files for a single class, even if you missed out implementing one method of an interface, the intellisense of Visual Studio .Net 2005 will point it out to you, thus enabling you to implement the missed out method of the interface. This is one among the advantage of using a Visual Studio .Net 2005 IDE for ASP.Net 2.0 applications.
This type of splitting the class file is particularly useful if a single class runs to thousands of lines of code with different functionalities across different methods. Productivity of the project team is increased since a single class file is split across the team members and implemented as partial classes.