ASP.NET: Revolution, not innovation

Figure A

The first three web server-side controls are quite intuitive: tag control (label), text box, and a submission letter. The last control, is different. A verification control checks the status of another control and prevents this form from being submitted when the target control is not in the correct state. In the Greter program, the RequiredFieldValidator control is used to verify that a data has been entered in the text box control. It doesn't care about the value of this data. In the initial state, the RequiredFieldValidator control is invisible. If the text box is empty when you are clicked, you will not generate a click message, and the RequiredFieldValidator control will display the properties of the errorMessage property, as shown in Figure B. For high versions of browsers, the RequiredFieldValidator control generates JavaScript to verify data on the client. For low version of browsers, you need to verify on the server side. ASP.NET also provides several verification controls in addition to the RequiredFieldValidator control. Figure B

Greterlogic class

GreeterLogic inherits from class system.web.ui.page. It declares several protected data domains to save references to controls created in the Greter.aspx file. Greterlogic defines two ways. OnInit method overloads the method to add a M_Button_Click method to the M_Button clicked event. The m_button_click method handles the click event generated by the M_Button web server-side control. This click event triggers a data transmission process to the server side. On the server side, ASP.NET restarts this page and then recover the status of the web server control. Now the value of the text box can be obtained by accessing the textboxText property. Figure C shows the response message generated by m_button_click.

Figure C

Configure the Greter program

To configure a Greter application, you can follow the steps below:

Create a directory for an application.

Create a bin subdirectory in the application's directory.

Place GREETER.ASPX in the application directory.

Use the command CSC / T: library /out:greter.dll Greeter.aspx.cs to compile Greter.aspx.cs into a library file and put Greter.dll in the BIN subdirectory of the application.

Create a IIS virtual directory pointing to the application directory.

.ASPX class

The ASP.NET application is processed by IIS ISAPI filter ASPNET_ISAPI.DLL. When you first access, the ISAPI filter generates a .NET class from Greter.aspx under the ASP namespace and compile it into a binary library file. IIS automatically searches for the BIN subdirectory of the application to find the GreterLogic base class. Figure D shows the inheritance relationship of the generated class. The generated binaries will be placed in a directory where the temporary ASP.NET file generated according to the virtual directory of the application. For example, if Greter's virtual directory is named by Introaspnet, Greter.aspx may generate a binary of Effla-HH.DLL and placed in C: /Winnt/Microsoft.Net/framework/v1.0.3328// Temporary ASP.NET FILES / INTROASPNET / B5D8B0AF / 51648AB7 in such a directory.

If Greter.aspx is modified, the ISAPI filter automatically regenerates binary files when the next page is accessed.

Figure D

ASP.NET is real-oriented

So what does all this mean? ASP.NET provides a true object-oriented programming model. WebForms can be created completely independent of the page logic, and combine it by inheritance. There will be no more inclusions of HTML and VBScript. The logic of the page is implemented using a full-featured .NET language, forces C #, Visual Basic.NET, or JScript.net. Further, the implementation process of page logic can use all the .NET base class libraries freely. The web server control encapsulates the difference between different web browsers and allows you to design the web page from a higher level. Everything will be compiled into a Microsoft Intermediate Language (MSIL) and can be converted into machine code synchronously at runtime. The performance loss that does not have existed in the interpretative page. If this is still not called a revolution, I really need a new dictionary :-). Listing A: Greter.aspx