Question

我想将一个Image添加到ListBox Item。

我有2张图片。一个是UpArrow，第二个是DownArrow

我可以使用ItemTemplate指定初始图像说UpArrow并向其添加图像

但是点击排序按钮，我想更改图像。新图像已设置但未在UI上更改。

我的窗口代码如下

<Window x:Class="WpfApplication1.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:WpfApplication1"
Title="Window1" Height="Auto" Width="Auto" Loaded="Window_Loaded">
<Window.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="Dictionary1.xaml"/>
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Window.Resources>
<Grid Height="Auto" Width="Auto">
    <Grid.RowDefinitions>
        <RowDefinition></RowDefinition>
        <RowDefinition></RowDefinition>
    </Grid.RowDefinitions>
    <ListBox x:Name="lstBox" ItemsSource="{Binding ListIconDataCollection}" Grid.Row="0" Height="200" Width="200">
        <ListBox.ItemTemplate>
            <DataTemplate DataType="{x:Type local:ListIconData}">
                <Grid Width="Auto" Height="Auto" Background="Transparent" >
                    <Grid.RowDefinitions>
                        <RowDefinition></RowDefinition>
                    </Grid.RowDefinitions>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="150"></ColumnDefinition>
                        <ColumnDefinition Width="Auto"></ColumnDefinition>
                    </Grid.ColumnDefinitions>
                    <TextBlock Grid.Row="0" Grid.Column="0" HorizontalAlignment="Stretch" Text="{Binding DisplayText}"/>
                    <Image  Grid.Row="0" Grid.Column="1" Source="{Binding Path=ImageSource}" Width="20" HorizontalAlignment="Right"/>
                </Grid>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>
    <Button Name="btnSort" Grid.Row="1" Height="40" Margin="0,15,0,0" Content="Sort" Click="btnSort_Click"></Button>

</Grid>

我的表单代码位于

之下

private void Window_Loaded(object sender, RoutedEventArgs e)
    {

        lstDataToSet.Add(new ListIconData { DisplayText = "Milind", ItemSortDirection = SortDirection.None, ImageSource = (ImageSource)FindResource("ImgUp") });
        lstDataToSet.Add(new ListIconData { DisplayText = "Patil", ItemSortDirection = SortDirection.None });

        lstBox.ItemsSource = ListIconDataCollection;
    }

这是执行的表单代码，但图片在UI上没有变化

private void btnSort_Click(object sender, RoutedEventArgs e)
    {
        ListIconData objSelectedItem = (ListIconData)lstBox.SelectedItem;
        if (objSelectedItem.ItemSortDirection==SortDirection.None)
        {
            objSelectedItem.ImageSource = null;
            objSelectedItem.ImageSource = (ImageSource)FindResource("ImgDown");

        }

    }

这是Dictionary1资源文件代码

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ImageSource x:Key="ImgUp">icons/Up.ico</ImageSource>
<ImageSource x:Key="ImgDown">icons/Down.ico</ImageSource>

以下是ListIconDataClass。这是我绑定到ListBox的列表

public class ListIconData
{
    public string DisplayText { get; set; }
    public SortDirection ItemSortDirection { get; set; }
    public ImageSource ImageSource { get; set; }
}

}

Answer 1

正如nikeee13建议您应该发送有关模型类中的更改的通知

public class ListIconData : INotifyPropertyChanged
{
    #region INotifyPropertyChanged implementation

    public event PropertyChangedEventHandler PropertyChanged;

    protected void OnPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }
    #endregion

    public string DisplayText { get; set; }
    public SortDirection ItemSortDirection { get; set; }

    private ImageSource imgSource;
    public ImageSource ImageSource { 
        get{return imgSource;} 
        set{
              if(imgSource == null || !imgSource.Equals(value))
              {
                 imgSource = value;
                 OnPropertyChanged("ImageSource");
              }
           } 
    }
}

Answer 2

private void btnSort_Click(object sender, RoutedEventArgs e)
    {
        **lstBox.BeginInit();**
        ListIconData objSelectedItem = (ListIconData)lstBox.SelectedItem;
        if (objSelectedItem.ItemSortDirection==SortDirection.None)
        {
            objSelectedItem.ImageSource = null;
            objSelectedItem.ImageSource = (ImageSource)FindResource("ImgDown");
        }
        **lstBox.EndInit();**

    }

请找到我添加的粗体中的代码行，以使其正常工作谢谢大家的帮助

WPF ListBox ItemTemplate图像

2 个答案: