Question

我正在使用ListBox来显示Dictionary＆lt;＆gt;中包含的所有值对象：

<ListBox Height="519" x:Name="ContactsListBox" Width="460" Margin="0,0,0,0" SelectionChanged="ContactsListBox_SelectionChanged">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <StackPanel Orientation="Vertical">
                    <TextBlock Text="{Binding Key}" Margin="5" Foreground="{StaticResource PhoneAccentBrush}"/>
                    <TextBlock x:Name ="LastNameData" Text="{Binding Value}" Margin="20, 0" />
                </StackPanel>
            </DataTemplate>
        </ListBox.ItemTemplate>
</ListBox>

内容由以下代码填写：

Dictionary<long, Contact> contacts = new Dictionary<long, Contact>();
this.ContactsListBox.ItemsSource = contacts;

现在，我想知道当前选择ListBox中哪个特定的“联系人”，或者通过知道它的Key，或者只是从“LastNameData”TextBlock中提取值。

我尝试过这样的事情，但显而易见它不起作用：

private void ContactsListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    ListBox lb = this.ContactsListBox.SelectedItem as ListBox;
    this.Test_SomeOtherTextBlock.Text = lb.ToString();
}

我真的很感谢你的帮助！

Answer 1

你甚至可以做下面的事情：

<ListBox Height="519" x:Name="ContactsListBox" Width="460" Margin="0,0,0,0" >
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Vertical">
                        <TextBlock Text="{Binding Key}" Margin="5"/>
                        <TextBlock x:Name ="LastNameData" Text="{Binding Value}" Margin="20, 0" />
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
        <Grid DataContext="{Binding ElementName=ContactsListBox, Path=SelectedItem}" Margin="0,470,0,0">
            <TextBlock Text="{Binding Value}"/>
        </Grid>

所以你不需要代码......

BR，

TJ

Answer 2

您的代码很好，使用ListBox.SelectedItem是正确的方法。

我认为问题在于您应该将其投放为ListBoxItem，而不是ListBox。并且还要使用DataContext来获得它的价值，所以像这样的行（未经测试，我不确定在最后一行中访问DataContext值）：

private void ContactsListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    ListBoxItem lbi = this.ContactsListBox.SelectedItem as ListBoxItem;
    var dataContext = lbi.DataContext;
    this.Test_SomeOtherTextBlock.Text = dataContext.Value.ToString();
}

Answer 3

有几个问题：

在Xaml中，您可能不希望显示类名，而是显示合理的字符串，例如：

<TextBlock x:Name ="LastNameData" Text="{Binding Value.LastName}" Margin="20, 0" />

在选择处理中，所选项目是KeyValuePair＆lt; ...＆gt;。如果你在调试器中查看返回的类型，你可以自己轻松找到它。（对于程序员来说应该是一种反射，因此上面的问题永远不会出现：））

private void ContactsListBox_SelectionChanged(object sender, SelectionChangedEventArgs e) { 
    KeyValuePair<long, Contact> kv = (KeyValuePair<long, Contact>)this.ContactsListBox.SelectedItem;
    Contact c = (Contact)kv.Value;
    Debug.WriteLine(c.LastName);
}

Answer 4

试试这个对我有用，会帮助你...

private void ListBox_SelectionChanged（object sender，SelectionChangedEventArgs e）

{

ListBox ContactListBox =发件人为ListBox;

ListBoxItem listBoxItem = ContactListBox .ItemContainerGenerator.ContainerFromItem（ContactListBox.SelectedItem）as ListBoxItem;

if（listBoxItem == null）

{

            return;

}

TextBlock txtBlock = FindVisualChildByName（listBoxItem，“ListTextBlock”）;

MessageBox.Show（txtBlock.Text）;

}

    private static T FindVisualChildByName<T>(DependencyObject parent, string name) where T : DependencyObject
    {
        for (int i = 0; i < VisualTreeHelper.GetChildrenCount(parent); i++)
        {
            var child = VisualTreeHelper.GetChild(parent, i);
            string controlName = child.GetValue(NameProperty) as string;
            if (controlName == name)
            {
                return child as T;
            }
            T result = FindVisualChildByName<T>(child, name);
            if (result != null)
                return result;
        }
        return null;
    }

Answer 5

private void ContactsListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    ListBox lb = this.ContactsListBox.SelectedItem as ListBox;
    this.Test_SomeOtherTextBlock.Text = lb.ToString();
}

会是这样的......


private void ContactsListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    ListBox lb = this.ContactsListBox.SelectedItem as ListBox;
    DataTemplate template=lb.ContentTemplate;
    //Now here you have to extract the content of the data template 
      and then you need to extract the TextBlock from that content.

}

这只是对功能的概述。很抱歉无法发布完整的代码。

如何从ListBox中选定的TextBlock元素中提取值？

5 个答案: