在WPF中，我正在使用BooleanToVisibilityConverter将一个控件的Visibility属性绑定到一个Boolean。这个方法是可行的，但是如果这个布尔值是true，我希望其中一个控件隐藏，如果它是false，则显示。
如何反转BooleanToVisibilityConverter？
169
- Andy
4
18个回答
3
这是我经常写和使用的代码。它使用一个布尔转换器参数来指示是否反转值，然后使用异或运算进行否定：
[ValueConversion(typeof(bool), typeof(System.Windows.Visibility))]
public class BooleanVisibilityConverter : IValueConverter
{
System.Windows.Visibility _visibilityWhenFalse = System.Windows.Visibility.Collapsed;
/// <summary>
/// Gets or sets the <see cref="System.Windows.Visibility"/> value to use when the value is false. Defaults to collapsed.
/// </summary>
public System.Windows.Visibility VisibilityWhenFalse
{
get { return _visibilityWhenFalse; }
set { _visibilityWhenFalse = value; }
}
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
bool negateValue;
Boolean.TryParse(parameter as string, out negateValue);
bool val = negateValue ^ System.Convert.ToBoolean(value); //Negate the value when negateValue is true using XOR
return val ? System.Windows.Visibility.Visible : _visibilityWhenFalse;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
bool negateValue;
Boolean.TryParse(parameter as string, out negateValue);
if ((System.Windows.Visibility)value == System.Windows.Visibility.Visible)
return true ^ negateValue;
else
return false ^ negateValue;
}
}
以下是XOR运算的真值表供参考：
XOR
x y XOR
---------
0 0 0
0 1 1
1 0 1
1 1 0
- xr280xr
2
你可以使用QuickConverter。
使用QuickConverter，你可以在BindingExpression中编写转换器逻辑。
下面是一个反向的BooleanToVisibility转换器：
您可以通过NuGet添加QuickConverter。 查看设置的文档。 链接：https://quickconverter.codeplex.com/
使用QuickConverter，你可以在BindingExpression中编写转换器逻辑。
下面是一个反向的BooleanToVisibility转换器：
Visibility="{qc:Binding '!$P ? Visibility.Visible : Visibility.Collapsed', P={Binding Example}}"
您可以通过NuGet添加QuickConverter。 查看设置的文档。 链接：https://quickconverter.codeplex.com/
- Felix Keil
2
我本想找到一个更为通用的答案，但未能如愿。我写了一个转换器，希望能帮助其他人。
它基于以下六种不同情况的区分：
- True 2 可见, False 2 隐藏
- True 2 可见, False 2 折叠
- True 2 隐藏, False 2 可见
- True 2 折叠, False 2 可见
- True 2 隐藏, False 2 折叠
- True 2 折叠, False 2 隐藏
以下是我实现的前四种情况：
[ValueConversion(typeof(bool), typeof(Visibility))]
public class BooleanToVisibilityConverter : IValueConverter
{
enum Types
{
/// <summary>
/// True to Visible, False to Collapsed
/// </summary>
t2v_f2c,
/// <summary>
/// True to Visible, False to Hidden
/// </summary>
t2v_f2h,
/// <summary>
/// True to Collapsed, False to Visible
/// </summary>
t2c_f2v,
/// <summary>
/// True to Hidden, False to Visible
/// </summary>
t2h_f2v,
}
public object Convert(object value, Type targetType,
object parameter, CultureInfo culture)
{
var b = (bool)value;
string p = (string)parameter;
var type = (Types)Enum.Parse(typeof(Types), (string)parameter);
switch (type)
{
case Types.t2v_f2c:
return b ? Visibility.Visible : Visibility.Collapsed;
case Types.t2v_f2h:
return b ? Visibility.Visible : Visibility.Hidden;
case Types.t2c_f2v:
return b ? Visibility.Collapsed : Visibility.Visible;
case Types.t2h_f2v:
return b ? Visibility.Hidden : Visibility.Visible;
}
throw new NotImplementedException();
}
public object ConvertBack(object value, Type targetType,
object parameter, CultureInfo culture)
{
var v = (Visibility)value;
string p = (string)parameter;
var type = (Types)Enum.Parse(typeof(Types), (string)parameter);
switch (type)
{
case Types.t2v_f2c:
if (v == Visibility.Visible)
return true;
else if (v == Visibility.Collapsed)
return false;
break;
case Types.t2v_f2h:
if (v == Visibility.Visible)
return true;
else if (v == Visibility.Hidden)
return false;
break;
case Types.t2c_f2v:
if (v == Visibility.Visible)
return false;
else if (v == Visibility.Collapsed)
return true;
break;
case Types.t2h_f2v:
if (v == Visibility.Visible)
return false;
else if (v == Visibility.Hidden)
return true;
break;
}
throw new InvalidOperationException();
}
}
例子：
Visibility="{Binding HasItems, Converter={StaticResource BooleanToVisibilityConverter}, ConverterParameter='t2v_f2c'}"
我认为这些参数很容易记住。希望能对某些人有所帮助。
- rmojab63
1
编写您自己的转换程序。
public class ReverseBooleanToVisibilityConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
// your converter code here
}
}
- Chris
0
将所有东西转换为任何东西（bool，string，enum等）：
public class EverythingConverterValue
{
public object ConditionValue { get; set; }
public object ResultValue { get; set; }
}
public class EverythingConverterList : List<EverythingConverterValue>
{
}
public class EverythingConverter : IValueConverter
{
public EverythingConverterList Conditions { get; set; } = new EverythingConverterList();
public object NullResultValue { get; set; }
public object NullBackValue { get; set; }
public object Convert(object value, Type targetType,
object parameter, CultureInfo culture)
{
return Conditions.Where(x => x.ConditionValue.Equals(value)).Select(x => x.ResultValue).FirstOrDefault() ?? NullResultValue;
}
public object ConvertBack(object value, Type targetType,
object parameter, CultureInfo culture)
{
return Conditions.Where(x => x.ResultValue.Equals(value)).Select(x => x.ConditionValue).FirstOrDefault() ?? NullBackValue;
}
}
XAML示例：
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:conv="clr-namespace:MvvmGo.Converters;assembly=MvvmGo.WindowsWPF"
xmlns:sys="clr-namespace:System;assembly=mscorlib">
<conv:EverythingConverter x:Key="BooleanToVisibilityConverter">
<conv:EverythingConverter.Conditions>
<conv:EverythingConverterValue ResultValue="{x:Static Visibility.Visible}">
<conv:EverythingConverterValue.ConditionValue>
<sys:Boolean>True</sys:Boolean>
</conv:EverythingConverterValue.ConditionValue>
</conv:EverythingConverterValue>
<conv:EverythingConverterValue ResultValue="{x:Static Visibility.Collapsed}">
<conv:EverythingConverterValue.ConditionValue>
<sys:Boolean>False</sys:Boolean>
</conv:EverythingConverterValue.ConditionValue>
</conv:EverythingConverterValue>
</conv:EverythingConverter.Conditions>
</conv:EverythingConverter>
<conv:EverythingConverter x:Key="InvertBooleanToVisibilityConverter">
<conv:EverythingConverter.Conditions>
<conv:EverythingConverterValue ResultValue="{x:Static Visibility.Visible}">
<conv:EverythingConverterValue.ConditionValue>
<sys:Boolean>False</sys:Boolean>
</conv:EverythingConverterValue.ConditionValue>
</conv:EverythingConverterValue>
<conv:EverythingConverterValue ResultValue="{x:Static Visibility.Collapsed}">
<conv:EverythingConverterValue.ConditionValue>
<sys:Boolean>True</sys:Boolean>
</conv:EverythingConverterValue.ConditionValue>
</conv:EverythingConverterValue>
</conv:EverythingConverter.Conditions>
</conv:EverythingConverter>
<conv:EverythingConverter x:Key="MarriedConverter" NullResultValue="Single">
<conv:EverythingConverter.Conditions>
<conv:EverythingConverterValue ResultValue="Married">
<conv:EverythingConverterValue.ConditionValue>
<sys:Boolean>True</sys:Boolean>
</conv:EverythingConverterValue.ConditionValue>
</conv:EverythingConverterValue>
<conv:EverythingConverterValue ResultValue="Single">
<conv:EverythingConverterValue.ConditionValue>
<sys:Boolean>False</sys:Boolean>
</conv:EverythingConverterValue.ConditionValue>
</conv:EverythingConverterValue>
</conv:EverythingConverter.Conditions>
<conv:EverythingConverter.NullBackValue>
<sys:Boolean>False</sys:Boolean>
</conv:EverythingConverter.NullBackValue>
</conv:EverythingConverter>
- Ali Yousefi
0
一个简单的单向版本，可以像这样使用：
可以这样实现：
Visibility="{Binding IsHidden, Converter={x:Static Ui:Converters.BooleanToVisibility}, ConverterParameter=true}
可以这样实现：
public class BooleanToVisibilityConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
var invert = false;
if (parameter != null)
{
invert = Boolean.Parse(parameter.ToString());
}
var booleanValue = (bool) value;
return ((booleanValue && !invert) || (!booleanValue && invert))
? Visibility.Visible : Visibility.Collapsed;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
- Gregor Slavec
0
如Zamir在评论中指出，如果您绑定到视图模型，迄今为止最简单的方法是创建另一个属性来绑定并反转布尔值，就像这样；
这是有条件的，前提是要绑定到底层模型。
注意：如果您的模型已经绑定，请不要忘记在源属性更改时触发反转属性的PropertyChanged事件。
public class YourViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private bool _showThing = false;
public bool ShowThing
{
get => _showThing;
protected set
{
// flag that THiS property has changed
_showThing = value;
NotifyPropertyChanged();
// don't forget to notify the inverse has changed too
NotifyPropertyChanged(nameof(HideThing));
}
}
public bool HideThing => !ShowThing;
protected void NotifyPropertyChanged([CallerMemberName] string propertyName = null)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
这是有条件的，前提是要绑定到底层模型。
注意：如果您的模型已经绑定，请不要忘记在源属性更改时触发反转属性的PropertyChanged事件。
- DiskJunky
-2
我知道这已经过时了，但是你不需要重新实现任何东西。
我的做法是像这样否定属性的值：
<!-- XAML code -->
<StackPanel Name="x" Visibility="{Binding Path=Specials, ElementName=MyWindow, Converter={StaticResource BooleanToVisibilityConverter}}"></StackPanel>
<StackPanel Name="y" Visibility="{Binding Path=NotSpecials, ElementName=MyWindow, Converter={StaticResource BooleanToVisibilityConverter}}"></StackPanel>
....
//Code behind
public bool Specials
{
get { return (bool) GetValue(SpecialsProperty); }
set
{
NotSpecials= !value;
SetValue(SpecialsProperty, value);
}
}
public bool NotSpecials
{
get { return (bool) GetValue(NotSpecialsProperty); }
set { SetValue(NotSpecialsProperty, value); }
}
它完美地运行了！
我有什么遗漏吗？
- OscarRyz
1
7你认为这是一个更简单的解决方案，对于单个属性来说可能是这样（但对于多个属性来说不可重用，必须为每个属性实现它）。然而我认为这不是实现的正确位置，因为它与视图模型/代码后台无关，而与视图有关。 - Mike Fuchs
网页内容由stack overflow 提供, 点击上面的可以查看英文原文，
原文链接
原文链接
public bool ShowMyControl { get { return !theValue; } }在WPF中 Visibility="{Binding MyModel.ShowMyControl, Converter={StaticResource BooleanToVisibilityConverter}}" - Zamir