可以在Window的生命周期事件SourceInitialized或比其更晚的事件如Loaded中注册快捷键。关闭Window时(Closed事件)会自动注销快捷键。
// 注册快捷键
protected override void OnSourceInitialized(EventArgs e)
{
base.OnSourceInitialized(e);
var hotKeyModel = new HotKeyModel("Ctrl+Shift+A", true, true, false, false, Keys.A);
this.GlobalHotkeyManager.RegisterGlobalHotKey(hotKeyModel, (model) =>
{
MessageBox.Show($"Hotkey pressed: {model.Name} ({model.Key})\nModifiers: {model.GetModifierKeys()}",
"Global Hotkey Triggered", MessageBoxButton.OK, MessageBoxImage.Information);
});
}// 注销快捷键
GlobalHotkeyManager.UnregisterGlobalHotKey("Ctrl+Shift+A");// 获取整个application成功注册的快捷键
IEnumerable<HotKeyModel> models = GlobalHotkeyManager.GetAllHotkeys();// 获取在指定Window上注册的快捷键
IEnumerable<HotKeyModel> models = GlobalHotkeyManager.GetHotkeysOnWindow(this);- 快捷键事件处理程序
action在创建window的UI 线程上执行，应当妥善处理它可能抛出的异常，避免导致UI线程崩溃。 - 其他进程或当前进程已经注册的快捷键，重复注册会失败。
- 如果多个进程使用相同的快捷键，先启动的先占用，后来者失败。
- 一个进程只能注销本进程已经注册的快捷键，无法注销另外一个进程的快捷键。
- 开发者可以随时注销已经注册的快捷键，也可以不用关心，
快捷键会在窗口关闭时自动注销。 - 一般是在主窗体的OnSourceInitialized注册快捷键，只要主窗体没被关闭，快捷键一直有效。
UserControl有依赖属性IsDescriptionColumnVisible,子控件DataGrid.
public bool IsDescriptionColumnVisible
{
get { return (bool)GetValue(IsDescriptionColumnVisibleProperty); }
set { SetValue(IsDescriptionColumnVisibleProperty, value); }
}DataGrid的Description Column的可见性绑定到依赖属性IsDescriptionColumnVisible,
如，Visibility="{Binding ElementName="userControl", Path=IsDescriptionColumnVisible, Converter={StaticResource Bool2VisibilityConverter}}"
但是会发现并不起作用。打开Visual Studio的Output窗口可以看到错误信息System.Windows.Data Error: 2 : Cannot find governing FrameworkElement or FrameworkContentElement for target element. BindingExpression:Path=IsDescriptionColumnVisible; DataItem=null; target element is 'DataGridTemplateColumn' (HashCode=53540541); target property is 'Visibility' (type 'Visibility')
总之就是DataGridTemplateColumn不在UserControl的可视化树上，导致绑定无效。
使用BindingProxy可以解决问题。在资源中定义BindingProxy，BindingProxy的DataContext与资源宿主的DataContext相同。
<UserControl.Resources>
<xp:BindingProxy x:Key="proxy" Data="{Binding ElementName=self}" />
</UserControl.Resources>
<DataGridTemplateColumn
Header="Description"
MinWidth="{Binding Source={StaticResource proxy}, Path=Data.DescColumnMinWidth}"
MaxWidth="{Binding Source={StaticResource proxy}, Path=Data.DescColumnMaxWidth}"
Visibility="{Binding Source={StaticResource proxy}, Path=Data.IsDescriptionColumnVisible, Converter={StaticResource Bool2VisibilityConverter}}">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<TextBlock Text="{Binding Description}" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
减少冒泡&隧道路由事件订阅次数的同时，还能将事件处理程序从XAML Code Behind 转移到 ViewModel，让代码更符合MVVM规范。
Bad Code
<StackPanel
x:Name="StackPanel"
Margin="0,10,0,0"
ButtonBase.Click="StackPanel_Click">
<Button
MinWidth="150"
Margin="10"
Padding="5"
HorizontalAlignment="Center"
Content="Move forward 10cm"
Tag="10" />
<Button
MinWidth="150"
Margin="10"
Padding="5"
HorizontalAlignment="Center"
Content="Move forward 20cm"
Tag="20" />
<Button
MinWidth="150"
Margin="10"
Padding="5"
HorizontalAlignment="Center"
Content="Move forward 30cm"
Tag="30" />
</StackPanel>更符合MVVM的好代码
<StackPanel x:Name="StackPanel" Margin="0,10,0,0">
<i:Interaction.Triggers>
<xp:RoutedEventTrigger RoutedEvent="{x:Static ButtonBase.ClickEvent}">
<prism:InvokeCommandAction Command="{Binding MoveCommand}" TriggerParameterPath="OriginalSource.Tag" />
</xp:RoutedEventTrigger>
</i:Interaction.Triggers>
<Button
MinWidth="150"
Margin="10"
Padding="5"
HorizontalAlignment="Center"
Content="Move forward 10cm"
Tag="10" />
<Button
MinWidth="150"
Margin="10"
Padding="5"
HorizontalAlignment="Center"
Content="Move forward 20cm"
Tag="20" />
<Button
MinWidth="150"
Margin="10"
Padding="5"
HorizontalAlignment="Center"
Content="Move forward 30cm"
Tag="30" />
</StackPanel>| Property | Description |
|---|---|
| MethodName | 指定要调用的方法名称 |
| Parameters | 指定方法的实参 |
| TargetObject | 方法所属的实例。默认值是CallMethodAction关联的WPF元素。 |
| PassTriggerArgsToMethod | 是否传递Trigger传递给CallMethodAction的Invoke(object args)的参数args作为Method的实参 |
| TriggerArgsConverter | 对Trigger传递的参数args进行转换（PassTriggerArgsToMethod等于True时生效） |
| TriggerArgsConverterParameter | 指定TriggerArgsConverter的object Convert(object value, Type targetType, object parameter, CultureInfo culture)的parameter实参（PassTriggerArgsToMethod等于True时生效） |
-
方法的形参可以是Parameters指定的实参的基类
如后续代码中，ViewModel的OnSubmit()的firstName的类型是object，但是Parameters传递的实参是string，但是程序运行正常。
还有void ShowMouseDownTime(MouseEventArgs e)，View传递到ViewModel的实参类型是MouseButtonEventArgs，程序依然正常运行。
-
Parameters指定实参的顺序和数量必须匹配方法的签名
-
方法签名必须是public的实例方法且无返回void
View
<StackPanel Orientation="Horizontal">
<!-- 提交姓名表单 （两个参数）-->
<StackPanel
Margin="5"
HorizontalAlignment="Center"
VerticalAlignment="Center">
<StackPanel VerticalAlignment="Center" Orientation="Horizontal">
<TextBlock Margin="0,0,20,0" Text="First Name:" />
<TextBox Name="FirstNameTxt" Width="200" />
</StackPanel>
<StackPanel
Margin="5"
VerticalAlignment="Center"
Orientation="Horizontal">
<TextBlock Margin="0,0,16,0" Text="Last Name:" />
<TextBox Name="LastNameTxt" Width="200" />
</StackPanel>
<Button Width="100" Content="Submit">
<i:Interaction.Triggers>
<i:EventTrigger EventName="Click">
<xp:CallMethodAction MethodName="OnSubmit" TargetObject="{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=DataContext}">
<xp:Parameter Value="{Binding ElementName=FirstNameTxt, Path=Text}" />
<xp:Parameter Value="{Binding ElementName=LastNameTxt, Path=Text}" />
</xp:CallMethodAction>
</i:EventTrigger>
</i:Interaction.Triggers>
</Button>
</StackPanel>
<!-- 关闭窗体 （无参） -->
<Button
Margin="30,0,0,0"
Padding="5"
VerticalAlignment="Center"
Content="Close Window">
<i:Interaction.Triggers>
<i:EventTrigger EventName="Click">
<xp:CallMethodAction MethodName="Close" TargetObject="{Binding RelativeSource={RelativeSource AncestorType=Window}}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</Button>
<!-- 显示鼠标信息 （传递事件原始参数）-->
<TextBlock
Margin="50,0,0,0"
VerticalAlignment="Center"
Text="Show Mouse Down Time">
<i:Interaction.Triggers>
<i:EventTrigger EventName="MouseDown">
<xp:CallMethodAction
MethodName="ShowMouseDownTime"
PassTriggerArgsToMethod="True"
TargetObject="{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=DataContext}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBlock>
</StackPanel>
ViewModel
internal class MainWindowViewModel
{
public void OnSubmit(object firstName,string lastName)
{
MessageBox.Show($"Hello {firstName} {lastName}!");
}
public void ShowMouseDownTime(MouseEventArgs e)
{
MessageBox.Show($"Mouse down at {e.Timestamp} ms");
}
}The library allows to create IValueConverter, IMultiValueConverter, DataTemplateSelector, and ValidationRule objects with the most convenient syntax available, ideally, using the lambda expressions.
First define your converters as static fields (or properties) in UserControl class:
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
public static readonly IValueConverter VisibleIfTrue = ValueConverter.Create<bool, Visibility>(
e => e.Value ? Visibility.Visible : Visibility.Collapsed);
}You're done! Just reference the converters with the x:Static expressions from your XAML files:
<Button Visibility="{Binding model.IsAvailable, Converter={x:Static local:MainWindow.VisibleIfTrue}}" />Features
- strongly-typed converters
- resource declaration not needed, just use the
x:Staticexpressions - separate class for each converter not needed anymore
- no redundant declarations: if you do not need the
ConvertBackmethod, don't define it; otherwise, just put the second lambda expression - full support for the remaining parameters of the
ConvertandConvertBackmethods: thecultureand theparameter(also strongly-typed) are accessible as well - if the conversion fails due to unexpected value types the optional error strategy can be specified
public static readonly IMultiValueConverter PipeLineFlowRate = MultiValueConverter.Create<object[], double>(
e =>
{
double flowRate = 0.0;
bool isValve1Open = System.Convert.ToBoolean(e.Values[0]);
if (isValve1Open)
{
flowRate += 1.0;
}
bool isValve2Open = System.Convert.ToBoolean(e.Values[1]);
if (isValve2Open)
{
flowRate += 1.0;
}
return flowRate;
});The library also allows to create DataTemplateSelector objects in the same convenient way as value converters. In order to define a selector simply write a static field (or property) similar to this snippet:
internal static class TemplateSelector
{
public static DataTemplateSelector AlternatingText =
LambdaConverters.TemplateSelector.Create<int>(
e => e.Item % 2 == 0
? (DataTemplate) ((FrameworkElement) e.Container)?.FindResource("BlackWhite")
: (DataTemplate) ((FrameworkElement) e.Container)?.FindResource("WhiteBlack"));
}Use your Lambda DataTemplateSelectors by referencing it with the x:Static markup extention (assuming that s is the namespace definition for the TemplateSelector class):
<UserControl.Resources>
<DataTemplate x:Key="BlackWhite">
<TextBlock Text="{Binding}" Foreground="Black" Background="White" />
</DataTemplate>
<DataTemplate x:Key="WhiteBlack">
<TextBlock Text="{Binding}" Foreground="White" Background="Black" />
</DataTemplate>
</UserControl.Resources>
<DockPanel>
<ListBox ItemsSource="{Binding IntNumbers}"
ItemTemplateSelector="{x:Static s:TemplateSelector.AlternatingText}">
</ListBox>
</DockPanel>Tada! All even numbers from IntNumbers are displayed with black font and white background and the odd numbers get the inverse font and background colors.
Features
- strongly-typed Selectors
- resource declaration not needed, just use the
x:Staticexpressions - separate class for each selector not needed anymore
- full support for the remaining parameter
container. For example, if you need to grab aDataTemplatefrom where the selector is use (see the example above).
Furthermore, you'll get Lambda ValidationRules on top. By now you know "the drill". First, define a ValidationRuleobject like this:
public static class Rule
{
public static ValidationRule IsNumericString =
LambdaConverters.Validator.Create<string>(
e => e.Value.All(char.IsDigit)
? ValidationResult.ValidResult
: new ValidationResult(false, "Text has non-digit characters!"));
}And then reference your new rule in vour View (assuming that r is the namespace definition for the Rule class):
<TextBox>
<TextBox.Text>
<Binding Path="Text" UpdateSourceTrigger="PropertyChanged">
<Binding.ValidationRules>
<x:Static Member="r:Rule.IsNumericString"/>
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>Now, you made sure that only strings which consists of digits are passed to your ViewModel.
Features
- strongly-typed rules
- resource declaration not needed, just use the
x:Staticexpressions - separate class for each rule not needed anymore
- full support for the remaining parameter
culture