crystal reports 2011 qr code Figure 2-2. The CreateSessionVars page on its first rendering in Visual C#

Printer ECC200 in Visual C# Figure 2-2. The CreateSessionVars page on its first rendering

Figure 2-2. The CreateSessionVars page on its first rendering
Make Data Matrix ECC200 In Visual C#
Using Barcode generation for .NET framework Control to generate, create DataMatrix image in .NET framework applications.
www.OnBarcode.com
Recognize Data Matrix ECC200 In C#.NET
Using Barcode scanner for .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
CHAPTER 2 THE ASP.NET REQUEST PIPELINE
Data Matrix ECC200 Drawer In Visual C#.NET
Using Barcode creation for VS .NET Control to generate, create DataMatrix image in .NET applications.
www.OnBarcode.com
Barcode Creator In C#.NET
Using Barcode printer for .NET Control to generate, create Barcode image in .NET applications.
www.OnBarcode.com
Here is the markup from CreateSessionVars.aspx. <%@ Page language="c#" CodeFile="CreateSessionVars.aspx.cs" Inherits="CreateSessionVars" %> <HTML> <HEAD> <title>CreateSessionVars</title> </HEAD> <body> <form id="Form1" method="post" runat="server"> How many variables <asp:TextBox Runat=server id=txtCount text=0 /> <asp:CompareValidator runat=server ControlToValidate=txtCount Operator=DataTypeCheck Type=Integer ErrorMessage='Must be an integer' Display=Dynamic /> <br><br> <asp:Button Runat=server ID=btnSubmit Text='Create them' /><br><br> <asp:Label Runat=server ID=lblOutput /> </form> </body> </HTML> And here are the Button Click and PreRender events from the code-behind of CreateSessionVars.aspx.cs. private void btnSubmit_Click(object sender, System.EventArgs e) { int Count = int.Parse(txtCount.Text) + Session.Keys.Count; for (int i = Session.Keys.Count; i < Count; i++) { Session[string.Format("sessionvar{0}",i)] = i; } } private void CreateSessionVars_PreRender(object sender, EventArgs e) { lblOutput.Text = string.Format( "Session count at start of request: {0}<br>" + "Session count at end of request: {1}<br>", this.SessionVarCount, Session.Keys.Count); } Since the preprocessor passes the session variable count into the Page property each time the page is requested, here s how the page renders after a 1 is posted back to the server (see Figure 2-3).
Linear Barcode Encoder In C#.NET
Using Barcode generator for .NET framework Control to generate, create 1D Barcode image in .NET applications.
www.OnBarcode.com
Code 39 Full ASCII Drawer In C#.NET
Using Barcode generator for .NET Control to generate, create Code 3/9 image in Visual Studio .NET applications.
www.OnBarcode.com
CHAPTER 2 THE ASP.NET REQUEST PIPELINE
Code 128 Code Set C Encoder In C#.NET
Using Barcode maker for .NET Control to generate, create Code 128 Code Set A image in Visual Studio .NET applications.
www.OnBarcode.com
Generating UCC - 12 In C#
Using Barcode generation for VS .NET Control to generate, create GTIN - 12 image in .NET applications.
www.OnBarcode.com
Figure 2-3. The CreateSessionVars page on its second rendering And then, after the first postback, here s the same page after a 3 is posted back (see Figure 2-4).
ECC200 Generation In None
Using Barcode creator for Office Excel Control to generate, create DataMatrix image in Excel applications.
www.OnBarcode.com
Data Matrix 2d Barcode Maker In C#
Using Barcode creator for VS .NET Control to generate, create Data Matrix 2d barcode image in .NET framework applications.
www.OnBarcode.com
Figure 2-4. The CreateSessionVars page on its third rendering By trapping the AcquireRequestState while preprocessing the page, you can keep track of how many Session variables are created during the lifetime of the request, regardless of where they re created. In this simple example you re only creating them in the Button Click event trap, but this pattern works even if you re creating or destroying Session variables in other preprocessors. The next event is PreRequestHandlerExecute. As you ll see in just a bit, any piece of code can process requests that come into the ASP .NET Framework by implementing the IHttpHandler interface. The main task in implementing this interface is to provide code
Draw EAN-13 In None
Using Barcode generation for Online Control to generate, create European Article Number 13 image in Online applications.
www.OnBarcode.com
Draw Barcode In None
Using Barcode creator for Online Control to generate, create Barcode image in Online applications.
www.OnBarcode.com
CHAPTER 2 THE ASP.NET REQUEST PIPELINE
UPCA Reader In Visual C#.NET
Using Barcode recognizer for VS .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Recognizing UCC - 12 In Visual C#.NET
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
for the ProcessRequest method. This is the last preprocessing event that fires before the ProcessRequest method is called on the handler. It s your last chance to do any pre-processing, before the code from your Page object starts executing. Almost everything is available to you from this event. The context has been long established, so the Request, Response, Cache, and Cookies are all available. Session state has been restored and is available. Plus, the context handler has been created and the HttpContext.Handler property has exposed an instance of it. In the case of Page processing, the only thing not available at this point are the values ViewState restores, as those don t move from the Post variables to the protected instance variables until the page is initialized. So you couldn t, for example, check the value of a textbox on a well-known Page type that had the textbox declared as public. You could, of course, still retrieve this value from the Post using Request.Form. (We ll examine more of ViewState in 4.) You re able to replace the handler at this point with one of your choosing: private void Global_PreRequestHandlerExecute (object sender, EventArgs e) { this.Context.Handler = new Dummy(); } This actually swaps out the handler just before ProcessRequest is called on it. The Dummy type in this example has to use the Page or another type that implements IHttpHandler as its base class, or explicitly provide an implementation of the IHttpHandler interface. In ASP .NET 2.0 you can also do this in the PostMapRequestHandler event. There are a lot of things you can break by doing this, but with careful planning, dynamically choosing a handler at runtime can be a powerful means to provide context- or user-specific handling of requests that are completely in your control. Another example is to create instances of User Controls depending on user preferences or authorizations, cast the handler into a known page type that exposes those User Controls as properties, and dynamically create instances of the appropriate controls and assign them to the properties. Keep in mind that this all occurs before any Page specific code is ever executed. The exception, of course, is the constructor, which has to be fired when the handler is first instantiated. Move initialization code from your constructor to the Page Init method override, and you can avoid issues that might otherwise arise. At this point the HttpApplication code calls ProcessRequest on the handler. We ll talk about custom handlers shortly. The Page handler has a well-known life cycle. Init is called. The Load event is fired. Control-specific events are fired, the Pre-Render event fires, and then the Unload event fires. (We examine this life cycle very closely in 3.) After the Page handler executes and renders, processing returns to the HttpApplication pipeline. The next event in this pipeline is PostRequestHandlerExecute. You can use PreRequestHandlerExecute and PostRequestHandlerExecute in pairs to box in the lifetime of a resource over the lifetime of the Page object. When communicating with the Page object, remember to use interfaces to avoid tight couplings between specific instances of Page objects and your more general pre- and post-processing code. As you ll see in the next section, the processors can be used not only across pages in a single application, but also, by implementing HttpModules, they can be reused across applications. Avoiding tight couplings between these processors and Page objects will make it easier to reuse them as your project grows to encompass more than one IIS application.
2D Barcode Encoder In VS .NET
Using Barcode generator for ASP.NET Control to generate, create 2D image in ASP.NET applications.
www.OnBarcode.com
Reading QR Code In C#
Using Barcode recognizer for .NET framework Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Reading Barcode In .NET
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Make Barcode In VS .NET
Using Barcode printer for .NET framework Control to generate, create Barcode image in VS .NET applications.
www.OnBarcode.com
Barcode Encoder In Visual Basic .NET
Using Barcode creator for .NET Control to generate, create Barcode image in VS .NET applications.
www.OnBarcode.com
UPCA Creation In Java
Using Barcode generator for Eclipse BIRT Control to generate, create UPC-A Supplement 2 image in BIRT reports applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.