WP7:根据另一个文本块的值更改文本块前景色 [英] WP7: Change Textblock Foreground color based on another Textblock's value

问题描述

假设我有这个 XAML:

Say I have this XAML:

<TextBlock Name="t1" Text="{Binding team1}" Foreground="White"  FontSize="32"   />
<ListBox Name="lbBooks" Width="441" Height="490" >
    <ListBox.ItemTemplate>
        <DataTemplate x:Name="d1" >
        <StackPanel Name="spMain">      
            <StackPanel Orientation="Horizontal" >                          
            <HyperlinkButton Content="{Binding BookName}" Margin="5" Width="230" TargetName="_blank" NavigateUri="{Binding BookWebsite}"/>

            <StackPanel Orientation="Vertical" HorizontalAlignment="Right" Margin="0,0,0,0" >
                <TextBlock Name="b1" Text="{Binding BookLine1}" Margin="5" Width="160" HorizontalAlignment="Right"></TextBlock>
                <TextBlock Name="b1U" Text="{Binding BookLine2}" Margin="5" Width="160" Foreground="Wheat" HorizontalAlignment="Right"></TextBlock>
                <TextBlock Name="b3" Text="{Binding BookLine3}" Margin="5" Width="160" DataContext="{Binding team1,Converter={StaticResource tbConverter}, ElementName=b3, Mode=TwoWay}"   HorizontalAlignment="Right"></TextBlock>
            </StackPanel>
        </StackPanel>       
        </StackPanel>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

我想根据 TextBlock "t1" 的值更改名为 "b3" 的 TextBlock 的前景色.我知道我需要实现一种如下所示的转换器:

I want to change the foreground color of the TextBlock named "b3" depending on the value of TextBlock "t1". I know I need to implement a converter kind of like the one below:

public class TBConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            //do I need to check against the Textblock t1 value in here?
            if (value != null && t1.Text == "Text that triggers change" ) 
            {
             //need code to change Textblock foreground color  
            }
            return null;
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    } 

那么，(1) 我需要在转换器中更改 Textblock b3 的前景色的代码是什么?(2)，我是否在 Textblockb3"的数据上下文中正确调用了转换器?谢谢！

So,(1) what is the code I need in the converter to change the foreground color of the Textblock b3? And (2), am I calling the converter correctly in the datacontext of Textblock "b3"? Thank you!

推荐答案

如果你的 textblock b1 已经绑定了一个变量(这里是 team1)，你也可以使用 Converter 绑定 t3 的 Foreground 到它:

If your textblock b1 is already binded to a variable (here team1), you can also bind Foreground of t3 to it with a Converter:

Foreground="{Binding team1, Converter={StaticResource YourConverter}}"

并且在您的转换器中，tema1 的值将作为值(对象)传递:

and in your converter the value of tema1 will be passed as the value (oject):

public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)              
{                  
   var team1 = valus as YourType
   if(team1 == xxx)
   {
     return newColorBrush;

   }else{

     return defaultColorBrush; //maybe from your styles etc...

   }

}    

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