C# 使用或代替AND的MultiDataTrigger
我正在尝试在我的C# 使用或代替AND的MultiDataTrigger,c#,wpf,xaml,button,visibility,C#,Wpf,Xaml,Button,Visibility,我正在尝试在我的按钮上设置多个数据触发器。我做了一些研究,发现MultiDataTrigger允许您这样做。如果CCTVPath==string.Empty或PermissionsFlag==false,我希望将我的按钮的可见性属性设置为false。这就是我目前所拥有的 <Button Grid.Column="3" x:Name="cctvFeedButton" Content="Live Feed" Width="100" FontSize="16" Horizonta
按钮上设置多个数据触发器
。我做了一些研究,发现MultiDataTrigger
允许您这样做。如果CCTVPath==string.Empty
或PermissionsFlag==false,我希望将我的按钮的可见性
属性设置为false。这就是我目前所拥有的
<Button Grid.Column="3" x:Name="cctvFeedButton" Content="Live Feed"
Width="100" FontSize="16" HorizontalAlignment="Right" Margin="5" Click="OnCCTVButtonClick">
<Button.Style>
<Style TargetType="Button">
<Style.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding CCTVPath}" Value=""/>
<Condition Binding="{Binding PermissionsFlag}" Value="False"/>
</MultiDataTrigger.Conditions>
<Setter Property="Visibility" Value="Hidden"/>
</MultiDataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>
正如您所看到的那样,PermissionsFlag
肯定是假的,并且肯定是空的CCTVPath
,但是按钮从来没有隐藏过。我做错了什么
更新:
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
private bool _permissionsFlag;
public bool Flag
{
get { return _permissionsFlag; }
set
{
_permissionsFlag = value;
OnPropertyChanged("PermissionsFlag");
}
}
private void OnPageLoaded(object sender, RoutedEventArgs e)
{
Flag = false;
CCTVImageCollection = GetImages();
imageListBox.ItemsSource = CCTVImageCollection;
DataContext = this;
}
在我的XAML中:
<Button.Style>
<Style TargetType="Button">
<Style.Triggers>
<DataTrigger Binding="{Binding PermissionsFlag}" Value="False">
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
将条件转换为两个独立的数据触发器
<Style.Triggers>
<DataTrigger Binding="{Binding CCTVPath}" Value="">
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>
<DataTrigger Binding="{Binding PermissionsFlag}" Value="False">
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>
</Style.Triggers>
窗口xaml:
<Window x:Class="WpfDemos.Views.Window3"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window3" Height="300" Width="300">
<StackPanel>
<CheckBox Name="chkPermissionsFlag"
Content="PermissionsFlag"
IsChecked="{Binding Path=PermissionsFlag, UpdateSourceTrigger=PropertyChanged}"/>
<TextBox Text="{Binding Path=CCTVPath, UpdateSourceTrigger=PropertyChanged}"/>
<Button x:Name="cctvFeedButton" Content="Live Feed"
Width="100" FontSize="16" HorizontalAlignment="Right" Margin="5">
<Button.Style>
<Style TargetType="Button">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=CCTVPath}" Value="">
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>
<DataTrigger Binding="{Binding Path=PermissionsFlag}" Value="False">
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>
</StackPanel>
</Window>
另一种解决方案是将单个数据触发器与多绑定一起使用。您可以通过定义一个“特殊情况”IMultiValueConverter使其工作,该IMultiValueConverter假定对象数组中有2项,如果第一项为空字符串或第二项为false,则返回true。但是,您可能永远不会在代码中的任何其他地方使用该转换器。因此,如果您愿意在前面做更多的工作,您可以定义3个简单/可重用的转换器
1) [IMultiValueConverter]“或Converter”,看起来像这样:
public class BooleanOrConverter : IMultiValueConverter {
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture) {
return values.OfType<bool>().Any(b => b);
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture) {
throw new NotImplementedException();
}
}
<Button x:Name="cctvFeedButton" Content="Live Feed"
Width="100" FontSize="16" HorizontalAlignment="Right" Margin="5">
<Button.Style>
<Style TargetType="Button">
<Style.Triggers>
<DataTrigger Value="True">
<DataTrigger.Binding>
<MultiBinding Converter="{StaticResource OrConverter}">
<Binding Path="PermissionFlag" Converter="{StaticResource NotConverter}"/>
<Binding Path="CCTVPath" Converter="{StaticResource IsNullOrEmptyConverter}"/>
</MultiBinding>
</DataTrigger.Binding>
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>
3) 和[IValueConverter]“NotConverter:”
public class BooleanNotConverter : IValueConverter {
public object Convert(object value, Type targetType, object parameter, CultureInfo culture) {
return !(bool)value;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) {
throw new NotImplementedException();
}
}
然后,在xaml中,DataTrigger的定义如下:
public class BooleanOrConverter : IMultiValueConverter {
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture) {
return values.OfType<bool>().Any(b => b);
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture) {
throw new NotImplementedException();
}
}
<Button x:Name="cctvFeedButton" Content="Live Feed"
Width="100" FontSize="16" HorizontalAlignment="Right" Margin="5">
<Button.Style>
<Style TargetType="Button">
<Style.Triggers>
<DataTrigger Value="True">
<DataTrigger.Binding>
<MultiBinding Converter="{StaticResource OrConverter}">
<Binding Path="PermissionFlag" Converter="{StaticResource NotConverter}"/>
<Binding Path="CCTVPath" Converter="{StaticResource IsNullOrEmptyConverter}"/>
</MultiBinding>
</DataTrigger.Binding>
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>
为了可读性,我更喜欢这个解决方案,而不是使用两个单独的DataTrigger;它更好地表达了您正在定义的行为-它是“或”逻辑:一组由2个条件组成的单一条件,应该隐藏按钮。谢谢您的时间。当我这样做时,即使当PermissionsFlag==false
按钮仍会显示时,我希望无论CCTVPath的值是多少,它都会被隐藏。我希望出现一些错误,就像我删除了CCTVPath
数据触发器一样,然后它再次不起我想要的作用。我可以在其中添加一个方法来实现这一点,还是需要一个全新的类来引发事件?你手头有好的例子吗?在页面的onload
方法中,我使用DataContext=this代码>PermissionsFlag
仅在页面内使用public bool PermissionsFlag{get;set;}
应OnPropertyChanged(“PermissionsFlag”)代码>更改属性(“\u permissionsFlag”)代码>?这是否也意味着我需要更改
我已经更新了我的问题,你能看到代码有什么问题吗?(它仍然没有隐藏按钮
)
<Button x:Name="cctvFeedButton" Content="Live Feed"
Width="100" FontSize="16" HorizontalAlignment="Right" Margin="5">
<Button.Style>
<Style TargetType="Button">
<Style.Triggers>
<DataTrigger Value="True">
<DataTrigger.Binding>
<MultiBinding Converter="{StaticResource OrConverter}">
<Binding Path="PermissionFlag" Converter="{StaticResource NotConverter}"/>
<Binding Path="CCTVPath" Converter="{StaticResource IsNullOrEmptyConverter}"/>
</MultiBinding>
</DataTrigger.Binding>
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>