我有一個multibinding看起來是這樣的:WPF - 延遲Multibinding
<UserControl.Visibility>
<MultiBinding Converter="{StaticResource isMouseOverToVisibiltyConverter}">
<Binding ElementName="otherElement" Path="IsMouseOver" />
<Binding RelativeSource="{RelativeSource Self}" Path="IsMouseOver" />
</MultiBinding>
</UserControl.Visibility>
而且,我希望能夠IsMouseOver去假兩個綁定之間添加延遲,能見度被設置爲崩潰了。
我發現這個DelayBinding實現: http://www.paulstovell.com/wpf-delaybinding
但是,這並不對MultiBinding工作,我一直無法弄清楚如何使一個與MultiBinding工作。
我確實可以選擇在代碼隱藏的事件中對可見性進行更改,這樣做會起作用,但如果有某種方法可以通過綁定系統執行此操作,那將會很不錯。
有沒有辦法給MultiBinding添加延遲?
編輯:雷,爲了讓你的類編譯&運行,我不得不做一些修復。但是,有些東西仍然是錯誤的,因爲更新沒有被傳播。它似乎只更新一次目標屬性。
[ContentProperty("Bindings")]
public class DelayedMultiBindingExtension : MarkupExtension, IMultiValueConverter, INotifyPropertyChanged
{
public Collection<BindingBase> Bindings { get; private set; }
public IMultiValueConverter Converter { get; set; }
public object ConverterParameter { get; set; }
public CultureInfo ConverterCulture { get; set; }
public BindingMode Mode { get; set; }
public UpdateSourceTrigger UpdateSourceTrigger { get; set; }
public object CurrentValue { get { return _delayedValue; } set { _delayedValue = _undelayedValue = value; _timer.Stop(); } }
private object _undelayedValue;
private object _delayedValue;
private DispatcherTimer _timer;
public int ChangeCount { get; private set; } // Public so Binding can bind to it
public DelayedMultiBindingExtension()
{
this.Bindings = new Collection<BindingBase>();
_timer = new DispatcherTimer();
_timer.Tick += _timer_Tick;
_timer.Interval = TimeSpan.FromMilliseconds(500);
}
public override object ProvideValue(IServiceProvider serviceProvider)
{
var valueProvider = serviceProvider.GetService(typeof(IProvideValueTarget)) as IProvideValueTarget;
if (valueProvider != null)
{
var bindingTarget = valueProvider.TargetObject as DependencyObject;
var bindingProperty = valueProvider.TargetProperty as DependencyProperty;
var multi = new MultiBinding { Converter = this, Mode = Mode, UpdateSourceTrigger = UpdateSourceTrigger };
foreach (var binding in Bindings)
multi.Bindings.Add(binding);
multi.Bindings.Add(new Binding("ChangeCount") { Source = this, Mode = BindingMode.OneWay });
var bindingExpression = BindingOperations.SetBinding(bindingTarget, bindingProperty, multi);
return bindingTarget.GetValue(bindingProperty);
}
return null;
}
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
object newValue =
Converter.Convert(
values.Take(values.Length - 1).ToArray(),
targetType,
ConverterParameter,
ConverterCulture ?? culture);
if (!object.Equals(newValue, _undelayedValue))
{
_undelayedValue = newValue;
_timer.Stop();
_timer.Start();
}
return _delayedValue;
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
{
return
Converter.ConvertBack(value, targetTypes, ConverterParameter, ConverterCulture ?? culture)
.Concat(new object[] { ChangeCount }).ToArray();
}
private void _timer_Tick(object sender, EventArgs e)
{
_timer.Stop();
_delayedValue = _undelayedValue;
ChangeCount++;
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs("ChangeCount"));
}
public event PropertyChangedEventHandler PropertyChanged;
}
EDIT2:雖然我不能讓雷的代碼工作中,我將其標記爲答案,因爲它導致了我的一些代碼,做的工作。查看我的答案,下面是我使用的代碼。
這個問題幫助我解決了我的問題,非常感謝! – worldpart 2017-10-17 20:30:59