EVENTS REFERENCED IN CODE in Visual Basic .NET

Printer QR Code 2d barcode in Visual Basic .NET EVENTS REFERENCED IN CODE

EVENTS REFERENCED IN CODE
QR Code 2d Barcode Creation In VB.NET
Using Barcode encoder for .NET framework Control to generate, create QR Code JIS X 0510 image in Visual Studio .NET applications.
www.OnBarcode.com
Reading QR Code In Visual Basic .NET
Using Barcode decoder for VS .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
To attach an event handler from code, you follow the same approach you would for any normal CLR event: create a new event handler and add it to the event using the += syntax. So, if we have the same button as earlier and give it a name that can be referenced from the code-behind:
Generating 1D Barcode In VB.NET
Using Barcode creator for VS .NET Control to generate, create Linear 1D Barcode image in .NET framework applications.
www.OnBarcode.com
Code 128B Generator In Visual Basic .NET
Using Barcode creation for .NET framework Control to generate, create Code-128 image in .NET framework applications.
www.OnBarcode.com
<Button x:Name="MyButton" />
Making Code 3 Of 9 In Visual Basic .NET
Using Barcode encoder for Visual Studio .NET Control to generate, create Code 3 of 9 image in VS .NET applications.
www.OnBarcode.com
Denso QR Bar Code Generator In VB.NET
Using Barcode printer for VS .NET Control to generate, create QR Code JIS X 0510 image in Visual Studio .NET applications.
www.OnBarcode.com
Download from Wow! eBook <www.wowebook.com>
Print UPC-A Supplement 2 In Visual Basic .NET
Using Barcode maker for .NET framework Control to generate, create GTIN - 12 image in Visual Studio .NET applications.
www.OnBarcode.com
Code 11 Printer In VB.NET
Using Barcode creator for .NET Control to generate, create USD - 8 image in VS .NET applications.
www.OnBarcode.com
Core XAML
Paint QR Code In None
Using Barcode drawer for Font Control to generate, create QR Code ISO/IEC18004 image in Font applications.
www.OnBarcode.com
Printing QR Code ISO/IEC18004 In C#
Using Barcode encoder for .NET framework Control to generate, create QR Code JIS X 0510 image in .NET applications.
www.OnBarcode.com
We can then wire up the event handler in the constructor. Do this after the InitializeComponent call so that MyButton is valid:
Generating UPCA In Visual C#
Using Barcode creator for .NET Control to generate, create GS1 - 12 image in .NET applications.
www.OnBarcode.com
Matrix 2D Barcode Generator In VS .NET
Using Barcode creator for VS .NET Control to generate, create Matrix Barcode image in Visual Studio .NET applications.
www.OnBarcode.com
public MainPage() { InitializeComponent(); MyButton.Click += new RoutedEventHandler(MyButton_Click); } private void MyButton_Click(object sender, RoutedEventArgs e) { MessageBox.Show("Click event"); }
Draw QR Code 2d Barcode In VS .NET
Using Barcode maker for ASP.NET Control to generate, create QR-Code image in ASP.NET applications.
www.OnBarcode.com
Print UPC - 13 In Objective-C
Using Barcode generation for iPad Control to generate, create EAN13 image in iPad applications.
www.OnBarcode.com
Both approaches are equally valid. The approach you use will depend primarily on your personal style. My preferred approach when not using commands is to wire up events in the code-behind, in the constructor as shown. Silverlight 4 added the ability to use commands as a way to clean up event handling and wire-up code. Rather than specify an event handler, you can specify one or more command properties in XAML.
Encode UPC-A Supplement 2 In Java
Using Barcode encoder for Java Control to generate, create UPC-A Supplement 5 image in Java applications.
www.OnBarcode.com
Paint Barcode In .NET Framework
Using Barcode creator for VS .NET Control to generate, create Barcode image in Visual Studio .NET applications.
www.OnBarcode.com
Commands
Making Code 3/9 In Visual Studio .NET
Using Barcode maker for Reporting Service Control to generate, create Code 3 of 9 image in Reporting Service applications.
www.OnBarcode.com
Recognize PDF417 In .NET
Using Barcode decoder for .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
One of the more architecturally significant additions to Silverlight 4 was the addition of WPF-style commands. Commands allow you to remove the event handler middleman from your code-behind when you want something other than the code-behind to handle the action. For example, if you follow the ViewModel pattern, you probably want the button clicks to be handled by the view model and not the code-behind. Typical event handler code to forward the event might look like this:
Barcode Generator In Objective-C
Using Barcode drawer for iPhone Control to generate, create Barcode image in iPhone applications.
www.OnBarcode.com
Create Barcode In None
Using Barcode generation for Online Control to generate, create Barcode image in Online applications.
www.OnBarcode.com
private void Save_Click(object sender, RoutedEventArgs e) { _viewModel.Save(); }
That s extra goo that you don t necessarily want in your view. It complicates unit testing and makes the code-behind an essential ingredient. It also requires separate viewmodel properties to set the IsEnabled property on the Save button. It s not terrible, but it s not great. The command code that eliminates the code-behind goo might look like this:
// no code in code-behind required :)
I love the code I don t have to write. It s all handled in the markup and the view model, so you don t need any forwarding code at all. The controls in the view bind to a command that exists somewhere in the binding path. Assuming you have the page s data context set to the view model, the markup to bind to the exposed view-model command looks like this:
<Button x:Name="SaveButton" Height="25"
Download from Wow! eBook <www.wowebook.com>
XAML basics
Width="75" Content="Save" Command="{Binding SaveCommand}" />
The related bits of the view model might look something like this, assuming you ve implemented an EmployeeSaveCommand that implements ICommand:
private EmployeeSaveCommand _saveCommand; public ICommand SaveCommand { get { return _saveCommand; } }
In this way, you avoid having your code-behind stand in the way of separating your view from your view model. Commands also provide other capabilities such as automatically disabling the associated controls if the command can t be run at that time via an implicit binding of the ICommand.CanExecute method with IsEnabled property of the Button. Commands are supported on any control that inherits from ButtonBase as well as on the Hyperlink control (not to be confused with HyperlinkButton, which inherits from ButtonBase). We ll create our own commands in chapter 16 when we discuss how to build applications using the ViewModel pattern. Another interesting bit of attached functionality you may see in the markup is a behavior.
Behaviors
Behaviors are bits of designer-friendly packaged interactivity introduced in Silverlight 3, originally tied to Expression Blend to make it easy to drag functionality directly onto the design surface and associate it with controls. Behaviors included capabilities such as physics, sound, automatic shadows, drag and drop, and even nonvisual behaviors such as one that s used to wire up the window-close events to a view model in WPF. The appeal was much broader than just Blend users, though, so the functionality was released for all Silverlight and WPF developers to enjoy. The SDK includes a number of default behaviors as well as a ton of community-created behaviors for both Silverlight and WPF on the Expression Figure 2.2 The default behaviors in Expression Blend include items from utilitarian, to sound community site. Figure 2.2 shows the playing, to complex interactions such as mouse Behaviors section of the Assets panel in drag and drop. Additional behaviors may be found Expression Blend, listing the eight on the Microsoft Expression Community Gallery included behaviors. at http://gallery.expression.microsoft.com.
Copyright © OnBarcode.com . All rights reserved.