vb net code 128 checksum Controller basics in .NET

Generation Code 128 Code Set A in .NET Controller basics

Controller basics
Code128 Maker In .NET
Using Barcode maker for ASP.NET Control to generate, create USS Code 128 image in ASP.NET applications.
www.OnBarcode.com
Creating Barcode In VS .NET
Using Barcode printer for ASP.NET Control to generate, create Barcode image in ASP.NET applications.
www.OnBarcode.com
Listing 4.5 shows that the success path is determined by the call to the ModelState.IsValid property B. The model binder translates the form post data into the UserInput object and also populates the ModelState object with metadata about the data type validation of the object. When all of the validation passes, the IsValid property is true. In this case, the UpdateUserFromInput method is called. The UpdateUserFromInput method updates the User object from the input model. Once the update occurs, a success message is put into TempData. TempData allows transient data to be passed between two consecutive requests to the web server. After the user has been redirected to the next action, the contents of TempData will be available to display to the user. The last line of code in the success path C returns a RedirectToRouteResult in order to redirect the user back to the Index action. This approach keeps the action simple and concise.
1D Generator In .NET
Using Barcode creator for ASP.NET Control to generate, create 1D Barcode image in ASP.NET applications.
www.OnBarcode.com
USS Code 128 Printer In VS .NET
Using Barcode drawer for ASP.NET Control to generate, create USS Code 128 image in ASP.NET applications.
www.OnBarcode.com
NOTE
Painting UCC-128 In Visual Studio .NET
Using Barcode printer for ASP.NET Control to generate, create EAN / UCC - 14 image in ASP.NET applications.
www.OnBarcode.com
Code39 Maker In .NET Framework
Using Barcode generation for ASP.NET Control to generate, create Code 39 Full ASCII image in ASP.NET applications.
www.OnBarcode.com
In this book, we focus on complex, long-lasting web applications. In keeping with that, we don t make compromises to optimize the speed of writing the application. Software engineering is full of trade-offs, and software construction techniques are no exception. If you need a small web application, you can probably get away with putting all the logic in the controller action, but realize that you re trading off long-term maintainability for short-term coding speed. If the application will have a long life, this is a bad trade-off. The examples in this book are factored for long life and easy maintenance.
PDF417 Encoder In .NET
Using Barcode creation for ASP.NET Control to generate, create PDF 417 image in ASP.NET applications.
www.OnBarcode.com
Print USPS Intelligent Mail In VS .NET
Using Barcode creator for ASP.NET Control to generate, create Intelligent Mail image in ASP.NET applications.
www.OnBarcode.com
Using the Post-Redirect-Get pattern
Code 128 Code Set A Maker In VS .NET
Using Barcode printer for .NET framework Control to generate, create Code 128A image in .NET framework applications.
www.OnBarcode.com
Recognize USS Code 128 In .NET Framework
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
The code in listing 4.5 demonstrates a pattern called Post-Redirect-Get (PRG), first published in 2003 by Michael Jouravlev. You saw this briefly in chapter 1. The pattern is used to prevent some common problems that occur after a user has posted a form to a web server. If a view is rendered directly from a form post, the user may attempt to refresh the browser or bookmark the page, which can cause double form submissions or other erroneous behavior. By redirecting after a form post to a URL that uses a GET request, the problem is eliminated. This makes the user experience consistent and deterministic. This pattern is often recommended when handling form posts. The screenshots in figures 4.2 and 4.3 demonstrate a form used to collect user input for an edit action. The success path of the action redirects to the Index page, and the page pulls the success message from TempData. The ASP.NET MVC Framework provides the components, like TempData and the RedirectToAction method, to support the PRG pattern.
Paint EAN13 In VS .NET
Using Barcode creation for Reporting Service Control to generate, create GTIN - 13 image in Reporting Service applications.
www.OnBarcode.com
Create Barcode In Java
Using Barcode generation for BIRT reports Control to generate, create Barcode image in Eclipse BIRT applications.
www.OnBarcode.com
Accepting input
Recognizing Data Matrix ECC200 In Visual C#.NET
Using Barcode decoder for VS .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
QR Code ISO/IEC18004 Drawer In None
Using Barcode encoder for Online Control to generate, create QR-Code image in Online applications.
www.OnBarcode.com
The user edit view
Decode Code-39 In Visual C#.NET
Using Barcode scanner for .NET framework Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Making Data Matrix 2d Barcode In Visual Studio .NET
Using Barcode printer for .NET Control to generate, create DataMatrix image in VS .NET applications.
www.OnBarcode.com
The redirected action showing a message from TempData
2D Generator In VB.NET
Using Barcode generation for VS .NET Control to generate, create 2D Barcode image in .NET framework applications.
www.OnBarcode.com
Painting Barcode In None
Using Barcode encoder for Microsoft Word Control to generate, create Barcode image in Office Word applications.
www.OnBarcode.com
Controller basics
Encode PDF417 In C#.NET
Using Barcode generation for .NET Control to generate, create PDF 417 image in Visual Studio .NET applications.
www.OnBarcode.com
ANSI/AIM Code 39 Scanner In Visual Basic .NET
Using Barcode recognizer for .NET framework Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Handling the failure processing of the action input Continuing the example of the Edit action, we ll now look at the alternate path that s followed when the call to ModelState.IsValid returns false. If the Username field is left blank when the form is posted to our controller, the automatic validation will fail because the Username property on the UserInput object is decorated with a RequiredAttribute (as shown in listing 4.6). In this case, the model binding infrastructure will automatically add an error message to the ModelState collection, which will cause the IsValid property to return false.
Listing 4.6 The alternate path Defines required property
public class UserInput { [Required] public string Username { get; set; } public string FirstName { get; set; } public string LastName { get; set; } } [HttpPost] public ActionResult Edit(UserInput input) { if (ModelState.IsValid) { ... } Returns input return View(input); }
model to view
Listing 4.6 shows that when the IsValid property returns false (indicating that there s at least one validation error), the UserInput instance is passed to the View method so that the error message can be rendered on the screen, as shown in figure 4.4.
Copyright © OnBarcode.com . All rights reserved.