WPF 标准命令 - 退出在哪里？
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WPF Standard Commands - Where's Exit?
提问by Andrew Shepherd
I'm creating a standard menu in my WPF application.
我正在我的 WPF 应用程序中创建一个标准菜单。
I know that I can create custom commands, but I know there are also a bunch of standard commands to bind to.
我知道我可以创建自定义命令，但我知道还有一堆标准命令要绑定。
For example, to open a file I should bind to ApplicationCommands.Open, to close a file I should bind to ApplicationCommands.Close. There's also a large number of EditCommands, ComponentCommandsor NavigationCommands.
例如，要打开一个文件，我应该绑定到ApplicationCommands.Open，要关闭一个文件，我应该绑定到ApplicationCommands.Close。还有大量的EditCommands、ComponentCommands或NavigationCommands。
There doesn't seem to be an "Exit" command. I would have expected there to be ApplicationCommands.Exit.
似乎没有“退出”命令。我原以为会有ApplicationCommands.Exit。
What should I bind to the "Exit" menu item? To create a custom command for something this generic just seems wrong.
我应该将什么绑定到“退出”菜单项？为这种通用的东西创建自定义命令似乎是错误的。
采纳答案by Thomas Levesque
AFAIK there's no ApplicationCommands.Quit or ApplicationCommands.Exit, so I guess you're gonna have to create it yourself...
AFAIK 没有 ApplicationCommands.Quit 或 ApplicationCommands.Exit，所以我猜你必须自己创建它......
Anyway, if you're using the MVVM pattern, RoutedCommands are not exactly handy, so it's better to use a lightweight alternative like RelayCommandor DelegateCommand.
无论如何，如果您使用的是MVVM 模式，RoutedCommands 并不是很方便，所以最好使用轻量级替代品，如RelayCommand或DelegateCommand。
回答by dthrasher
Unfortunately, there is no predefined ApplicationCommands.Exit. Adding one to WPF was suggested on Microsoft Connect in 2008: http://connect.microsoft.com/VisualStudio/feedback/details/354300/add-predefined-wpf-command-applicationcommands-exit. The item has been marked closed/postponed, however.
不幸的是，没有预定义的 ApplicationCommands.Exit。2008 年在 Microsoft Connect 上建议向 WPF 添加一个：http: //connect.microsoft.com/VisualStudio/feedback/details/354300/add-predefined-wpf-command-applicationcommands-exit。然而，该项目已被标记为关闭/推迟。
Mike Taulty discussed how to create your own Exit commandin an article on his blog.
Mike Taulty在他博客上的一篇文章中讨论了如何创建自己的退出命令。
回答by NoOne
Not that complex actually (but still, M$ sucks for not providing it). Here you go:
实际上并没有那么复杂（但 M$ 仍然很糟糕，因为没有提供它）。干得好：
public static class MyCommands
{
private static readonly ICommand appCloseCmd = new ApplicationCloseCommand();
public static ICommand ApplicationCloseCommand
{
get { return appCloseCmd; }
}
}
//===================================================================================================
public class ApplicationCloseCommand : ICommand
{
public event EventHandler CanExecuteChanged
{
// You may not need a body here at all...
add { CommandManager.RequerySuggested += value; }
remove { CommandManager.RequerySuggested -= value; }
}
public bool CanExecute(object parameter)
{
return Application.Current != null && Application.Current.MainWindow != null;
}
public void Execute(object parameter)
{
Application.Current.MainWindow.Close();
}
}
And the body of the AplicationCloseCommand.CanExecuteChangedevent handler may not be even needed.
AplicationCloseCommand.CanExecuteChanged甚至可能不需要事件处理程序的主体。
You use it like so:
你像这样使用它：
<MenuItem Header="{DynamicResource MenuFileExit}" Command="MyNamespace:MyCommands.ApplicationCloseCommand"/>
Cheers!
干杯!
(You cannot imagine how long it took me to discover this Command stuff myself...)
（你无法想象我花了多长时间自己发现这个命令的东西......）
回答by Peter Duniho
Yes, it would've made a lot of sense for Microsoft to include an ApplicationCommands.Exitcommand in their collection of pre-defined commands. It disappoints me that they didn't. But as the answers to this question demonstrate, not all is lost.
是的，微软ApplicationCommands.Exit在他们的预定义命令集合中包含一个命令是很有意义的。令我失望的是他们没有。但正如这个问题的答案所表明的那样，并不是所有的都丢失了。
There are lots of workarounds possible for the lack of a proper ApplicationCommands.Exitobject. However, I feel most miss the point. Either they implement something in the view model, for something that really is strictly a view behavior (in some cases reaching into the view object graph with e.g. Application.Current.MainWindow!), or they write a bunch of code-behind to do what XAML does very well and much more conveniently.
由于缺少合适的ApplicationCommands.Exit对象，有很多可能的解决方法。但是，我觉得最没有抓住重点。他们要么在视图模型中实现一些东西，对于一些真正严格来说是视图行为的东西（在某些情况下，使用例如Application.Current.MainWindow！）方便多了。
IMHO, the simplest approach is just to declare a RoutedUICommandresource for the window, attach that to a command binding, and to a menu item, to hook all the parts up. For example:
恕我直言，最简单的方法是RoutedUICommand为窗口声明一个资源，将其附加到命令绑定和菜单项，将所有部分连接起来。例如：
<Window x:Class="ConwaysGameOfLife.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Window.Resources>
<RoutedUICommand x:Key="fileExitCommand" Text="File E_xit">
<RoutedUICommand.InputGestures>
<KeyGesture >Alt+F4</KeyGesture>
</RoutedUICommand.InputGestures>
</RoutedUICommand>
</Window.Resources>
<Window.CommandBindings>
<CommandBinding Command="{StaticResource fileExitCommand}" Executed="fileExitCommand_Executed"/>
</Window.CommandBindings>
<DockPanel>
<Menu DockPanel.Dock="Top">
<MenuItem Header="_File">
<!-- other menu items go here -->
<Separator/>
<MenuItem Command="{StaticResource fileExitCommand}"/>
</MenuItem>
</Menu>
<!-- the main client area UI goes here -->
</DockPanel>
</Window>
The Executedevent handler for the command binding is trivial:
Executed命令绑定的事件处理程序很简单：
private void fileExitCommand_Executed(object sender, ExecutedRoutedEventArgs e)
{
Close();
}
Assuming, of course, your program implementation follows the usual semantics of closing the main window to exit the program.
当然，假设您的程序实现遵循关闭主窗口以退出程序的常用语义。
In this way, all of the UI-specific elements go right into the RoutedUICommandobject, which can be configured correctly and conveniently right in the XAML rather than having to declare a new C# class to implement the command and/or mess around with the input bindings from code-behind. The MenuItemobject already knows what to do with a RoutedUICommandin terms of display, so going this route provides a nice decoupling of the command's properties from the rest of the UI. It also provides a convenient way to provide a secondary key gesture, in case you'd prefer something other than the default Alt+F4(e.g. Ctrl+W).
通过这种方式，所有特定于 UI 的元素都直接进入RoutedUICommand对象，可以在 XAML 中正确且方便地对其进行配置，而不必声明新的 C# 类来实现命令和/或处理输入绑定从代码隐藏。该MenuItem物体已经知道如何与做RoutedUICommand在显示器方面，所以去这条路线提供了一个很好的从UI的其他命令的属性去耦。它还提供了一种方便的方式来提供辅助键手势，以防您更喜欢默认值以外的其他内容Alt+F4（例如Ctrl+W）。
You can even put the RoutedUICommanddeclaration in the App.xaml file, for reuse among multiple windows in your program, should they exist. Again, decoupling the UI-specific aspects, which are declared in the resource, from the consumers that are found throughout the program.
您甚至可以将RoutedUICommand声明放在 App.xaml 文件中，以便在程序中的多个窗口之间重用，如果它们存在的话。同样，将资源中声明的特定于 UI 的方面与整个程序中发现的使用者分离。
I find this approach much more generalizable and easily implemented than the other options which I've seen presented (here and elsewhere).
我发现这种方法比我看到的其他选项（这里和其他地方）更易于推广和易于实现。
回答by Alex
private void MenuItem_Click(object sender, RoutedEventArgs e)
{
Application.Current.Shutdown();
}
回答by Maxence
Pretty simple to do:
做起来很简单：
using System.Windows.Input;
namespace YourApp
{
static class ApplicationCommands
{
public static RoutedCommand Quit { get; }
static ApplicationCommands()
{
var inputGestures = new InputGestureCollection();
inputGestures.Add(new KeyGesture(Key.Q, ModifierKeys.Control));
Quit = new RoutedUICommand("Quit", "Quit", typeof(ApplicationCommands),
inputGestures);
}
}
}
Use it in your XAML like this:
在您的 XAML 中使用它，如下所示：
<Window.CommandBindings>
<CommandBinding Command="local:ApplicationCommands.Quit"
Executed="QuitCommandOnExecuted"/>
</Window.CommandBindings>
[..]
<MenuItem Command="local:ApplicationCommands.Quit" />
Code-behind:
代码隐藏：
void QuitCommandOnExecuted(object sender, ExecutedRoutedEventArgs e)
{
Application.Current.Shutdown();
}
回答by karl.r
You can modify the Text property of a command before you bind it in a window. This will change the text of the command everywhere it appears in your ui.
您可以在将命令绑定到窗口之前修改它的 Text 属性。这将更改出现在 ui 中的所有命令文本。
EDIT: Do this to Close in the Window or App ctor
编辑：执行此操作以在窗口或应用程序中关闭
