基于布尔值的 ListView 项目可见性

Posted 2023-02-21

【中文标题】基于布尔值的 ListView 项目可见性

【英文标题】：ListView item visibility based on boolean

【发布时间】：2017-06-23 10:59:59

【问题描述】：

我正在尝试根据输入文本过滤 ListView 项目，并且由于选择被删除，我正在尝试根据布尔值将可见性设置为不可见（我希望这不会删除项目的选择）

我使用了一些较早的帖子来创建此代码，但我无法弄清楚它为什么不起作用：

 <ListView x:Name="osebe_listView" Margin="0,0,40,0"  SelectionMode="Multiple"  SelectionChanged="osebe_listView_SelectionChanged" BorderThickness="0" ScrollViewer.HorizontalScrollBarVisibility="Hidden">

            <ListView.Resources>

                <Style TargetType="x:Type ListViewItem">
                    <Style.Triggers>
                        <DataTrigger Binding="Binding visible" Value="False">
                            <Setter Property="Visibility" Value="Hidden"/>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
                <Style TargetType="x:Type GridViewColumnHeader">
                    <Setter Property="Background" Value="#1AFFFFFF" />
                    <Setter Property="BorderThickness" Value="0"/>
                </Style>
                <Style TargetType="x:Type ColumnDefinition">
                    <Setter Property="Width" Value="10"/>
                </Style>

            </ListView.Resources>

            <ListView.View>
                <GridView>
                    <GridViewColumn Header="Naziv podjetja" DisplayMemberBinding="Binding nazivPodjetja"/>
                    <GridViewColumn Header="Ime" DisplayMemberBinding="Binding ime" Width="25"/>
                    <GridViewColumn Header="Priimek" DisplayMemberBinding="Binding priimek" Width="Binding ActualWidth, ElementName=helperField"/>
                    <GridViewColumn Header="Naslov" DisplayMemberBinding="Binding naslov" Width="Binding ActualWidth, ElementName=helperField"/>
                    <GridViewColumn Header="Pošta" DisplayMemberBinding="Binding posta" Width="Binding ActualWidth, ElementName=helperField"/>
                    <GridViewColumn Header="Mobilna številka" DisplayMemberBinding="Binding mobilnaSt" Width="Binding ActualWidth, ElementName=helperField"/>
                    <GridViewColumn Header="Stacionarna številka" DisplayMemberBinding="Binding stacionarnaSt" Width="Binding ActualWidth, ElementName=helperField"/>
                    <GridViewColumn Header="E-naslov" DisplayMemberBinding="Binding eMail" Width="Binding ActualWidth, ElementName=helperField"/>
                    <GridViewColumn Header="Skupina" DisplayMemberBinding="Binding skupina" Width="Binding ActualWidth, ElementName=helperField"/>
                </GridView>
            </ListView.View>
        </ListView>

文本过滤方法（效果很好）：

  private void isci_tb_TextChanged(object sender, TextChangedEventArgs e)
    
        try
        
            if (isci_tb.Text == "search") return;
            string s = isci_tb.Text;
            if (isci_tb.Text == "")
            
                foreach (Oseba o in seznamOseb)
                
                    //osebe_listView.Items.Add(o);
                    o.visible = true;
                
            
            //else
            //
          //  osebe_listView.Items.Clear();
                foreach (Oseba o in seznamOseb)
                
                    if(! (contejns(o.ime, s) || contejns(o.priimek, s) || contejns(o.mobilnaSt.ToString(), s) || contejns(o.posta, s) || contejns(o.nazivPodjetja, s) || contejns(o.stacionarnaSt.ToString(), s) || contejns(o.naslov, s) || contejns(o.eMail, s)))
                    
                    o.visible = false;
                    
                
            //
        
        catch  
    

我找到了code here

请注意，我没有使用任何数据绑定。我错过了什么？

【问题讨论】：

Oseba 类是否实现了 INotifyPropertyChanged 接口？

在他使用<Setter Property="Visibility" Value="Collapsed"/>的链接中，在您的代码中找不到。 o.visible 什么也没做，我猜..

它没有。我该如何实施？我认为这样设置属性就足够了，因为我在那篇文章中没有找到任何额外的代码

【参考方案1】：

确保Oseba 类实现INotifyPropertyChanged 接口并在visible 属性的设置器中引发PropertyChanged 事件：

public class Oseba : INotifyPropertyChanged

    private bool _isVisible;
    public bool visible
    
        get  return _isVisible; 
        set  _isVisible = value; NotifyPropertyChanged("visible"); 
    

    public event PropertyChangedEventHandler PropertyChanged;
    protected void NotifyPropertyChanged(string propertyName)
    
        if (PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    

这是动态触发ListViewItem 样式的数据触发器所必需的。

您还应该使用DataTrigger 将ListView 的ItemContainerStyle 属性设置为您的自定义样式：

<ListView x:Name="osebe_listView" Margin="0,0,40,0"  SelectionMode="Multiple"  SelectionChanged="osebe_listView_SelectionChanged" BorderThickness="0" ScrollViewer.HorizontalScrollBarVisibility="Hidden">
    <ListView.ItemContainerStyle>
        <Style TargetType="x:Type ListViewItem">
            <Style.Triggers>
                <DataTrigger Binding="Binding visible" Value="False">
                    <Setter Property="Visibility" Value="Hidden"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </ListView.ItemContainerStyle>
    <ListView.Resources>
        <Style TargetType="x:Type GridViewColumnHeader">
            <Setter Property="Background" Value="#1AFFFFFF" />
            <Setter Property="BorderThickness" Value="0"/>
        </Style>
        <Style TargetType="x:Type ColumnDefinition">
            <Setter Property="Width" Value="10"/>
        </Style>
    </ListView.Resources>

    <ListView.View>
        <GridView>
            <GridViewColumn Header="Naziv podjetja" DisplayMemberBinding="Binding nazivPodjetja"/>
            <GridViewColumn Header="Ime" DisplayMemberBinding="Binding ime" Width="25"/>
            <GridViewColumn Header="Priimek" DisplayMemberBinding="Binding priimek" Width="Binding ActualWidth, ElementName=helperField"/>
            <GridViewColumn Header="Naslov" DisplayMemberBinding="Binding naslov" Width="Binding ActualWidth, ElementName=helperField"/>
            <GridViewColumn Header="Pošta" DisplayMemberBinding="Binding posta" Width="Binding ActualWidth, ElementName=helperField"/>
            <GridViewColumn Header="Mobilna številka" DisplayMemberBinding="Binding mobilnaSt" Width="Binding ActualWidth, ElementName=helperField"/>
            <GridViewColumn Header="Stacionarna številka" DisplayMemberBinding="Binding stacionarnaSt" Width="Binding ActualWidth, ElementName=helperField"/>
            <GridViewColumn Header="E-naslov" DisplayMemberBinding="Binding eMail" Width="Binding ActualWidth, ElementName=helperField"/>
            <GridViewColumn Header="Skupina" DisplayMemberBinding="Binding skupina" Width="Binding ActualWidth, ElementName=helperField"/>
        </GridView>
    </ListView.View>
</ListView>

【讨论】：

成功了，非常感谢！它也不会像我希望的那样删除选择。为什么需要这个接口？据我了解，该属性会触发事件或类似事件？对不起，我知识贫乏，我才一年 C# :)

在绑定客户端和数据源之间的绑定中需要更改通知，如 MSDN 上的文档所述：msdn.microsoft.com/en-us/library/…

好的会调查的。我做到了，我猜，一旦我达到代表的门槛，它就会显示出来。 :)