WPF:绑定到ComboBox SelectedItem [英] WPF: Binding to ComboBox SelectedItem

问题描述

我有一个带有基于XML数据的ComboBox的UserControl:

I have a UserControl with ComboBox that based on XML data:

<Root>
<Node Background="Yellow" Foreground="Cyan" Image="1.ico" Property="aaaa" Value="28" />
<Node Background="SlateBlue" Foreground="Black" Image="2.ico" Property="bbbb" Value="2.5" />
<Node Background="Teal" Foreground="Green" Image="3.ico" Property="cccc" Value="4.0" />
<Node Background="Yellow" Foreground="Red" Image="4.ico" Property="dddd" Value="0" /></Root>

这是UserControl XAML:

Here is the UserControl XAML:

<UserControl x:Class="xxxxxxxx.MyComboBox"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         x:Name="myComboBoxControl">
<UserControl.Resources>
    <DataTemplate x:Key="dataTemplateNode">
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto" MinWidth="20"/>
                <ColumnDefinition Width="*"/>
                <ColumnDefinition Width="Auto" MinWidth="20"/>
            </Grid.ColumnDefinitions>
            <Border Background="{Binding XPath=@Background}" Grid.Column="0">
                <Image Source="{Binding XPath=@Image}" 
                       Width="16" 
                       Height="16" 
                       Margin="3" />
            </Border>
            <Border Background="{Binding XPath=@Background}" Grid.Column="1">
                <TextBlock Foreground="{Binding XPath=@Foreground}" 
                           Margin="3"
                           Text="{Binding XPath=@Property}" />
            </Border>
            <Border Background="{Binding XPath=@Background}" Grid.Column="2">
                <TextBlock Foreground="{Binding XPath=@Foreground}" 
                           Margin="3" 
                           FontWeight="Bold"
                           Text="{Binding XPath=@Value}" />
            </Border>
        </Grid>
    </DataTemplate>

    <XmlDataProvider x:Key="xmlNodeList" 
                     Source="/data/Combo.xml" 
                     XPath="/Root/Node"/>
</UserControl.Resources>

<ComboBox Name="myComboBox" 
          ItemsSource="{Binding Source={StaticResource xmlNodeList}}" 
          ItemTemplate="{StaticResource dataTemplateNode}"
          HorizontalContentAlignment="Stretch" /></UserControl>

在MainForm.xaml中，我有一个文本框，我想绑定到我的UserControl SelectedItem.

In the MainForm.xaml I have a TextBox that I want to bind to the my UserControl SelectedItem.

<StackPanel Orientation="Horizontal">
<local:MyComboBox1 x:Name="comboBoxST" />
<TextBox x:Name="textBoxST"/></StackPanel>

如果您能指导我该怎么做，我会很高兴.

I will glad if you will guid me how to do that.

提前谢谢！

推荐答案

此处的窍门是，当您必须绑定到绑定到XML的ItemControl上的SelectedItem时，所选项目本身就是XmlElement，并且必须使用XPath以获得所需的元素/属性.

The trick here is that when you have to bind to the SelectedItem on an ItemControl bound to XML, the selected item itself is an XmlElement, and you have to use XPath to get to the needed element/attribute.

最简单的方法是使用DataContext:

The easiest way to achieve this is to use DataContext:

<TextBox x:Name=textBoxST 
    DataContext="{Binding ElementName=comboBoxST, Path=SelectedItem}" 
    Text="{Binding XPath=@Value}"/>

这篇关于WPF:绑定到ComboBox SelectedItem的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！