Andy De George
da363692ff
* Reset branch for WPF changes * Convert BMP to PNG; fix link-out-of-scope err * Add snippets for WPF... 6794 files!!!! * Add missing snippets * update file updated between migration * Fix paths to include * update breadcrumb and toc * fix index links * fix index links * fix index links * fix markdown
4.7 KiB
title, ms.date, dev_langs, helpviewer_keywords, ms.assetid
| title | ms.date | dev_langs | helpviewer_keywords | ms.assetid | |||
|---|---|---|---|---|---|---|---|
| How to: Create a RoutedCommand | 03/30/2017 |
|
|
aaf6979f-69ab-406f-979f-5766daa85fa0 |
How to: Create a RoutedCommand
This example shows how to create a custom xref:System.Windows.Input.RoutedCommand and how to implement the custom command by creating a xref:System.Windows.Input.ExecutedRoutedEventHandler and a xref:System.Windows.Input.CanExecuteRoutedEventHandler and attaching them to a xref:System.Windows.Input.CommandBinding. For more information on commanding, see the Commanding Overview.
Example
The first step in creating a xref:System.Windows.Input.RoutedCommand is defining the command and instantiating it.
[!code-csharpCommandingOverviewSnippets#CommandingOverviewCommandDefinition] [!code-vbCommandingOverviewSnippets#CommandingOverviewCommandDefinition]
In order to use the command in an application, event handlers which define what the command does must be created
[!code-csharpCommandingOverviewSnippets#CommandingOverviewExecuted] [!code-vbCommandingOverviewSnippets#CommandingOverviewExecuted]
[!code-csharpCommandingOverviewSnippets#CommandingOverviewCanExecute] [!code-vbCommandingOverviewSnippets#CommandingOverviewCanExecute]
Next, a xref:System.Windows.Input.CommandBinding is created which associates the command with the event handlers. The xref:System.Windows.Input.CommandBinding is created on a specific object. This object defines the scope of the xref:System.Windows.Input.CommandBinding in the element tree
[!code-xamlCommandingOverviewSnippets#CommandingOverviewWindowCommandBindingXAML]
[!code-csharpCommandingOverviewSnippets#CommandingOverviewCustomCommandBindingCodeBehind] [!code-vbCommandingOverviewSnippets#CommandingOverviewCustomCommandBindingCodeBehind]
The final step is invoking the command. One way to invoke a command is to associate it with a xref:System.Windows.Input.ICommandSource, such as a xref:System.Windows.Controls.Button.
[!code-xamlCommandingOverviewSnippets#CommandingOverviewCustomCommandSourceXAML]
[!code-csharpCommandingOverviewSnippets#CommandingOverviewCustomCommandSourceCodeBehind] [!code-vbCommandingOverviewSnippets#CommandingOverviewCustomCommandSourceCodeBehind]
When the Button is clicked, the xref:System.Windows.Input.RoutedCommand.Execute%2A method on the custom xref:System.Windows.Input.RoutedCommand is called. The xref:System.Windows.Input.RoutedCommand raises the xref:System.Windows.Input.CommandManager.PreviewExecuted and xref:System.Windows.Input.CommandManager.Executed routed events. These events traverse the element tree looking for a xref:System.Windows.Input.CommandBinding for this particular command. If a xref:System.Windows.Input.CommandBinding is found, the xref:System.Windows.Input.ExecutedRoutedEventHandler associated with xref:System.Windows.Input.CommandBinding is called.