Provides a standard set of media related commands.
Assembly: PresentationCore (in PresentationCore.dll)
Thetype exposes the following members.
|BoostBass||Gets the value that represents the Boost Base command.|
|ChannelDown||Gets the value that represents the Channel Down command.|
|ChannelUp||Gets the value that represents the Channel Up command.|
|DecreaseBass||Gets the value that represents the Decrease Bass command.|
|DecreaseMicrophoneVolume||Gets the value that represents the Decrease Microphone Volume command.|
|DecreaseTreble||Gets the value that represents the Decrease Treble command.|
|DecreaseVolume||Gets the value that represents the Decrease Volume command.|
|FastForward||Gets the value that represents the Fast Forward command.|
|IncreaseBass||Gets the value that represents the Increase Bass command.|
|IncreaseMicrophoneVolume||Gets the value that represents the Increase Microphone Volume command.|
|IncreaseTreble||Gets the value that represents the Increase Treble command.|
|IncreaseVolume||Gets the value that represents the Increase Volume command.|
|MuteMicrophoneVolume||Gets the value that represents the Mute Microphone Volume command.|
|MuteVolume||Gets the value that represents the Mute Volume command.|
|NextTrack||Gets the value that represents the Next Track command.|
|Pause||Gets the value that represents the Pause command.|
|Play||Gets the value that represents the Play command.|
|PreviousTrack||Gets the value that represents the Previous Track command.|
|Record||Gets the value that represents the Record command.|
|Rewind||Gets the value that represents the Rewind command.|
|Select||Gets the value that represents the Select command.|
|Stop||Gets the value that represents the Stop command.|
|ToggleMicrophoneOnOff||Gets the value that represents the Toggle Microphone On Off command.|
|TogglePlayPause||Gets the value that represents the Toggle Play Pause command.|
The commands in the class and commands in the other command library classes, such as ComponentCommands and ApplicationCommands, are intended to represent a set of common commands that application programmers encounter frequently. The commands only represent the instance of the RoutedCommand and not the implementation logic for the command. The implementation logic is bound to the command via a CommandBindings. For example, if the Play command is executed on a control (the command target), the logic which performs the Play command may not be provided by the command target, so the application writer will be responsible for writing the logic that determines how the command target will handle the command.
Many controls do provide implementation logic for many of the commands in the command library. For example, the TextBox class provides logic for the Paste command, Cut command, Copy command, Undo command, and Redo command.
For more information on commands and commanding see the Commanding Overview.
The following example shows how to hook up a RoutedCommand to a Control which has built in support for the command. For a complete sample which hooks up commands to multiple sources, see the Create a Custom RoutedCommand Sample sample.
Windows Presentation Foundation (WPF) provides a library of common commands which application programmers encounter regularly. The classes which comprise the command library are: ApplicationCommands, ComponentCommands, NavigationCommands, , and EditingCommands.
The static RoutedCommand objects which make up these classes do not supply command logic. The logic for the command is associated with the command with a CommandBinding. Some controls have built in CommandBindings for some commands. This mechanism allows the semantics of a command to stay the same, while the actual implementation is can change. A TextBox, for example, handles the Paste command differently than a control designed to support images, but the basic idea of what it means to paste something stays the same. The command logic cannot be supplied by the command, but rather must be supplied by the control or the application.
Many controls in WPF do have built in support for some of the commands in the command library. TextBox, for example, supports many of the application edit commands such as Paste, Copy, Cut, Redo, and Undo. The application developer does not have to do anything special to get these commands to work with these controls. If the TextBox is the command target when the command is executed, it will handle the command using the CommandBinding that is built into the control.
The following shows how to use a MenuItem as the command source for the Paste command, where a TextBox is the target of the command. All the logic that defines how the TextBox performs the paste is built into the TextBox control.
A MenuItem is created and it's Command property is set to the Paste command. The CommandTarget is not explicitly set to the TextBox object. When the CommandTarget is not set, the target for the command is the element which has keyboard focus. If the element which has keyboard focus does not support the Paste command or cannot currently execute the paste command (the clipboard is empty, for example) then the MenuItem would be grayed out.
<Window x:Class="SDKSamples.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MenuItemCommandTask" > <DockPanel> <Menu DockPanel.Dock="Top"> <MenuItem Command="ApplicationCommands.Paste" Width="75" /> </Menu> <TextBox BorderBrush="Black" BorderThickness="2" Margin="25" TextWrapping="Wrap"> The MenuItem will not be enabled until this TextBox gets keyboard focus </TextBox> </DockPanel> </Window>
|How to: Hook Up a Command to a Control with No Command Support||The following example shows how to hook up a RoutedCommand to a Control which does not have built in support for the command. For a complete sample which hooks up commands to multiple sources, see the Create a Custom RoutedCommand Sample sample.|