Question

这是我到目前为止尝试在列表框项目（List）中实现渐变背景，具体取决于数据表对象的int值

我的对象简化形式：

public class Item {
 public string name { get; set; }
 public string address { get; set; }
 public int highlight { get; set; }
}

转换器尝试：

使用此转换器：

public class BusinessTypeToBackgroundConverter : IValueConverter
{
    private static readonly LinearGradientBrush NormalBkg = new LinearGradientBrush
    {
        StartPoint = new Point(0, 0),
        EndPoint = new Point(0, 1),
        GradientStops = new GradientStopCollection
                            {
                                new GradientStop {Color = Util.GetColorFromHex("#4ce6e6e6")},
                                new GradientStop {Color = Util.GetColorFromHex("#ffe6e6e6")}
                            }
    };

    private static readonly LinearGradientBrush HighlightedBkg = new LinearGradientBrush
    {
        StartPoint = new Point(0, 0),
        EndPoint = new Point(0, 1),
        GradientStops = new GradientStopCollection
                                                {
                                                    new GradientStop {Color = Util.GetColorFromHex("#4cffffcc")},
                                                    new GradientStop {Color = Util.GetColorFromHex("#ffffffcc")}
                                                }
    };

    public object Convert(object value, Type targetType,
                    object parameter, CultureInfo culture)
    {
        switch ((int)value)
        {
            case 1:
                return HighlightedBkg;
            case 2:
                return NormalBkg;
            default:
                return NormalBkg;
        }
    }

    public object ConvertBack(object value, Type targetType,
                              object parameter, CultureInfo culture)
    {
        throw new NotImplementedException("BusinessTypeToBackgroundConverter ConvertBack Method Not Implemented");
    }
}

这个项目模板

<ListBox                     
Name="lstResults" 
ItemContainerStyle="{StaticResource ListBoxItemStyle1}">
<ListBox.ItemTemplate>
    <DataTemplate>                           
        <Grid Background="{Binding highlight, Converter={StaticResource myConverter}}">
            <StackPanel>
                <TextBlock Text="{Binding name}" TextWrapping="Wrap" FontSize="24" FontWeight="Bold" Foreground="Black"/>
                <TextBlock Text="{Binding address}" TextWrapping="Wrap" FontSize="24" Foreground="Black" />
            </StackPanel>
        </Grid>
    </DataTemplate>
</ListBox.ItemTemplate>
</ListBox>

尝试后面的代码

为我的Item对象添加了“LinearGradientBrush background”属性

public LinearGradientBrush background
{
    get
    {
        if (highlight == 1) return HighlightedBkg;
        else return NormalBkg;
    }
}

在这两种情况下，只有渐变的开始颜色应用于listItem（网格背景）。所以我最终得到一个纯色的颜色:)

无论如何将背景ti设置为代码中的渐变并且不使用XAML表示法：

<LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
    <GradientStopCollection>
        <GradientStop Color="#ff444444" Offset="0" />
        <GradientStop Color="#ff000000" Offset="1" />
    </GradientStopCollection>
</LinearGradientBrush>

Answer 1

问题是，当您在代码中指定Gradient停靠点时，您没有指定偏移量。

但是我建议你不要避免Xaml的解决方案。首先阅读此博客：A Generic Boolean Value Converter。我还建议您的Hightlight属性应该是bool类型而不是int。

通过在项目中包含博客的转换器代码，您应该可以执行以下操作： -

<Grid x:Name="LayoutRoot">
   <Grid.Resources>
       <local:BoolToBrushConverter x:Key="Highlighter">
            <local:BoolToBrushConverter.TrueValue>
                <LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
                  <GradientStopCollection>
                <GradientStop Color="#4cffffcc" Offset="0" />
                <GradientStop Color="#ffffffcc" Offset="1" />
                  </GradientStopCollection>
                 </LinearGradientBrush>
            </local:BoolToBrushConverter.TrueValue>
            <local:BoolToBrushConverter.FalseValue>
                <LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
                  <GradientStopCollection>
                <GradientStop Color="#4ce6e6e6" Offset="0" />
                <GradientStop Color="#ffe6e6e6" Offset="1" />
                  </GradientStopCollection>
                 </LinearGradientBrush>
            </local:BoolToBrushConverter.FalseValue>
       </local:BoolToBrushConverter>
   </Grid.Resources>

<ListBox                     
Name="lstResults" 
ItemContainerStyle="{StaticResource ListBoxItemStyle1}">
<ListBox.ItemTemplate>
    <DataTemplate>                           
        <Grid Background="{Binding highlight, Converter={StaticResource Highlighter}}">
            <StackPanel>
                <TextBlock Text="{Binding name}" TextWrapping="Wrap" FontSize="24" FontWeight="Bold" Foreground="Black"/>
                <TextBlock Text="{Binding address}" TextWrapping="Wrap" FontSize="24" Foreground="Black" />
            </StackPanel>
        </Grid>
    </DataTemplate>
</ListBox.ItemTemplate>
</ListBox>

这种方法不仅可以让您以更熟悉的Xaml方式保持视觉描述，而且更灵活，更灵活。

Answer 2

您需要将背景绑定更改为Background="{Binding highlight, Converter={StaticResource myConverter}}"

根据ItemSource Databinded Value将ListBox项背景设置为LinearGradientBrush

2 个答案: