【发布时间】：2015-02-05 10:03:04
【问题描述】：
我在 WPF 中的 KeyBinding 中的绑定有问题。我正在使用带有 MVVM 模式的 WPF 开发 .net 3.5 项目。每当输入一些字母时，我都必须发出命令。不幸的是，Command 和 CommandParameter 在这个 .net 版本中不是依赖属性，我无法绑定到它们。因此，我编写了附加属性以从我的视图模型中分配命令和命令参数。但是绑定到它们不起作用，当我将绑定更改为文本（在命令参数中）时，CommandBindingParameterChanged 会上升，但当绑定到参数时它不会上升。我厌倦了设置窗口的名称并将其传递给绑定，但它也不起作用。但是当我将相同的命令分配给按钮时，它工作正常。这是我的代码 sn-p：
附加属性：
public class Helper
{
public static readonly DependencyProperty CommandBindingProperty = DependencyProperty.RegisterAttached("CommandBinding", typeof(ICommand), typeof(Helper), new FrameworkPropertyMetadata(default(ICommand), FrameworkPropertyMetadataOptions.None, CommandChanged));
public static ICommand GetCommandBinding(DependencyObject o)
{
return (ICommand)o.GetValue(CommandBindingProperty);
}
public static void SetCommandBinding(DependencyObject o, ICommand value)
{
o.SetValue(CommandBindingProperty, value);
}
private static void CommandChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var input = d as InputBinding;
input.Command = (ICommand)e.NewValue;
}
public static readonly DependencyProperty CommandBindingParameterProperty = DependencyProperty.RegisterAttached("CommandBindingParameter", typeof(object), typeof(Helper), new PropertyMetadata(CommandParameterChanged));
private static void CommandParameterChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var input = d as InputBinding;
if (input != null)
input.CommandParameter = e.NewValue;
}
public static object GetCommandBindingParameter(DependencyObject o)
{
return o.GetValue(CommandBindingParameterProperty);
}
public static void SetCommandBindingParameter(DependencyObject o, object value)
{
o.SetValue(CommandBindingParameterProperty, value);
}
}
视图模型
public class MainWindowViewModel : ViewModelBase
{
private string _text;
public string Text
{
get { return _text; }
set
{
_text = value;
RaisePropertyChanged("Text");
}
}
private bool _parameter;
public bool Parameter
{
get { return _parameter; }
set
{
_parameter = value;
RaisePropertyChanged("Parameter");
}
}
public MainWindowViewModel()
{
Parameter = true;
}
private RelayCommand<bool> _someCommand;
public ICommand SomeCommand
{
get { return _someCommand ?? (_someCommand = new RelayCommand<bool>(Execute, CanExecute)); }
}
private bool CanExecute(bool arg)
{
return arg;
}
private void Execute(bool obj)
{
//do something
}
}
XAML：
<Window x:Class="Test.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525"
xmlns:local="clr-namespace:Test"
Name="Window"
DataContext="{Binding Main, Source={StaticResource Locator}}"
>
<Grid>
<StackPanel>
<TextBox Text="{Binding Text}">
<TextBox.InputBindings>
<KeyBinding Key="A" local:Helper.CommandBinding="{Binding DataContext.SomeCommand, ElementName=Window}" local:Helper.CommandBindingParameter="{Binding DataContext.Parameter, ElementName=Window}"/>
</TextBox.InputBindings>
</TextBox>
<Button Content="SomeButton" Command="{Binding SomeCommand}" CommandParameter="{Binding Parameter}"/>
</StackPanel>
</Grid>
【问题讨论】：
标签： wpf mvvm wpf-controls dependency-properties