本章在WPF使用Thumb实现拖动和改变控件大小-1的基础上做修改
Selected属性
控件应该是被选中之后再显示ResizeThumb
public bool Selected
{
get { return (bool)GetValue(SelectedProperty); }
set { SetValue(SelectedProperty, value); }
}
// Using a DependencyProperty as the backing store for SelectedProperty. This enables animation, styling, binding, etc...
public static readonly DependencyProperty SelectedProperty =
DependencyProperty.Register("Selected", typeof(bool), typeof(MoveResizeItem), new PropertyMetadata(false));Selected为依赖属性，因为在WPF中必须是依赖属性才能作为绑定源。
<ContentControl.Resources>
<cvt:BoolVisualConvertion x:Key="BOOL_VISUAL_CVT"/>
</ContentControl.Resources>
<Grid Visibility="{Binding Selected, Converter={StaticResource BOOL_VISUAL_CVT}}">
...
</Grid>用Grid将8个ReszeThumb包裹，否则Selected的绑定要写8次...
转换器BoolVisualConvertion定义如下：
namespace MoveResizeItem.Converter
{
internal class BoolVisualConvertion : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
bool? b = value as bool?;
if (b == null)
{
return Visibility.Hidden;
}
return b == true ? Visibility.Visible : Visibility.Hidden;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
Visibility? v = value as Visibility?;
v = v == null ? Visibility.Hidden : Visibility.Visible;
return v;
}
}
}