CaptureUnCaptureMouse捕获鼠标

关注点：
1、 获取 捕获鼠标按钮的名字 的显示

1. 两种方法：一是直接获取GotMouseCapture路由事件中确定事件引发者e.source的名字
2. 二是新建一个IInputElement，获取鼠标捕获的元素Mouse.Captured；得到按钮的引用即可

// GotMouseCapture event handler
// MouseEventArgs.source is the element that has mouse capture
private void ButtonGotMouseCapture(object sender, MouseEventArgs e)
{var source = e.Source as Button;if (source != null){// Update the Label that displays the sample results.lblHasMouseCapture.Content = source.Name;}// Another way to get the element with Mouse Capture// is to use the static Mouse.Captured property.else{// Mouse.Capture returns an IInputElement.IInputElement captureElement;captureElement = Mouse.Captured;// Update the Label that displays the element with mouse capture.lblHasMouseCapture.Content = captureElement.ToString();}
}

2、 点击Capture Mouse按钮时，使RaidoButton指示的鼠标 执行 被鼠标捕获状态。此时鼠标变大？？就像鼠标放于按钮上状态。。。答：根据按钮上鼠标捕获定义，意味着捕获鼠标就是默认鼠标在按钮上拖移状态。

private void OnCaptureMouseRequest(object sender, RoutedEventArgs e)
{Mouse.Capture(_elementToCapture);
}private IInputElement _elementToCapture;private void OnRadioButtonSelected(object sender, RoutedEventArgs e)
{var source = e.Source as RadioButton;if (source != null){switch (source.Content.ToString()){case "1":_elementToCapture = Button1;break;case "2":_elementToCapture = Button2;break;case "3":_elementToCapture = Button3;break;case "4":_elementToCapture = Button4;break;}}
}

CommandSourceControlUsingSystemTime使用系统时间做比较值的命令源控件

1、实现效果

1. 滑块的滚动、点击的增减值设置
2. 同步显示当前时间秒数
3. 执行命令绑定方法，及判断命令查询状态

2、关键词

1. CommandBinding
2. Slider.DecreaseSmall.Execute
3. Timer.Elasped

3、静态组织
window的命令绑定设置:

1. Command绑定到window的一个静态自定义路由命令
2. 命令附加执行方法Executed，自定义方法附加到此句柄
3. 命令能否执行CanExecute,附加判断方法，返回bool

<!-- Command Binding for the Custom Command -->
<Window.CommandBindings><CommandBinding Command="{x:Static local:MainWindow.CustomCommand}"Executed="CustomCommandExecuted"CanExecute="CustomCommandCanExecute" />
</Window.CommandBindings>

完整滑块状态设置：

<Border BorderBrush="DarkBlue"BorderThickness="1"Height="75"Width="425"><StackPanel Orientation="Horizontal"><Button Command="Slider.DecreaseSmall"CommandTarget="{Binding ElementName=secondSlider}"Height="25"Width="25"Content="-"/><Label VerticalAlignment="Center">0</Label><Slider Name="secondSlider"Minimum="0"Maximum="60"Value="15"TickFrequency="5"Height="50"Width="275" TickPlacement="BottomRight"LargeChange="5"SmallChange="5" AutoToolTipPlacement="BottomRight" AutoToolTipPrecision="0"MouseWheel="OnSliderMouseWheel"MouseUp="OnSliderMouseUp" /><Label VerticalAlignment="Center">60</Label><Button Command="Slider.IncreaseSmall"CommandTarget="{Binding ElementName=secondSlider}"Height="25"Width="25"Content="+"/></StackPanel>
</Border>

4、动态流程
设置计时器：显示随时间秒数更新的时间数字

1. 新建计时器类Timer,引发时间间隔事件Elapsed
2. 设置时间间隔及激活计时器
3. 线程调度执行同步委托
4. Label显示现在时间秒数，同时强制更新注册命令状态

// System Timer setup.
var timer = new Timer();
timer.Elapsed += timer_Elapsed;
timer.Interval = 1000;
timer.Enabled = true;// System.Timers.Timer.Elapsed handler
// Places the delegate onto the UI Thread's Dispatcher
private void timer_Elapsed(object sender, ElapsedEventArgs e)
{// Place delegate on the Dispatcher.Dispatcher.Invoke(DispatcherPriority.Normal,new TimerDispatcherDelegate(TimerWorkItem));
}// Method to place onto the UI thread's dispatcher.
// Updates the current second display and calls
// InvalidateRequerySuggested on the CommandManager to force the
// Command to raise the CanExecuteChanged event.
private void TimerWorkItem()
{// Update current second display.lblSeconds.Content = DateTime.Now.Second;// Forcing the CommandManager to raie the RequerySuggested event.CommandManager.InvalidateRequerySuggested();
}

判断命令能否执行：

// CanExecute Event Handler.
//
// True if the current seconds are greater than the target value that is
// set on the Slider, which is defined in the XMAL file.
private void CustomCommandCanExecute(object sender, CanExecuteRoutedEventArgs e)
{if (secondSlider != null){e.CanExecute = DateTime.Now.Second > secondSlider.Value;}else{e.CanExecute = false;}
}

滑块中轮滚动事件，引起滑块值增减固定值

1. 获取滑块引用
2. 判断滚动方向值，增减滑块值Slider.DecreaseSmall.Execute

private void OnSliderMouseWheel(object sender, MouseWheelEventArgs e)
{var source = e.Source as Slider;if (source != null){if (e.Delta > 0){// Execute the Slider DecreaseSmall RoutedCommand.// The slider.value propety is passed as the command parameter.Slider.DecreaseSmall.Execute(source.Value, source);}else{// Execute the Slider IncreaseSmall RoutedCommand.// The slider.value propety is passed as the command parameter.Slider.IncreaseSmall.Execute(source.Value, source);}}
}

ps：此示例的e.Prameter为空，不显示秒数。