wpf - TabControl:SelectedContent 和 SelectedItem 返回相同

Question

我正在动态显示自定义对象列表(此处:Customer)，每个对象都使用 TabControl、ItemsSource 和 DataTemplate 在自己的选项卡中显示:

主Windows.xaml.cs:

using System.Collections.Generic;
using System.Diagnostics;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;

namespace testTabControl
{
    public class Customer
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int NumberOfContracts { get; set; }
    } 

    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            //create all
            var customers = new List<Customer>
            {
                new Customer {FirstName = "Jim", LastName = "Smith", NumberOfContracts = 23},
                new Customer {FirstName = "Jane", LastName = "Smiths", NumberOfContracts = 42},
                new Customer {FirstName = "John", LastName = "Tester", NumberOfContracts = 32}
            };

            //show
            myTabControl.ItemsSource = customers;

        }

        private void OnSizeChanged(object sender, SizeChangedEventArgs e)
        {
            Trace.WriteLine("myTabControl.SelectedContent is " + myTabControl.SelectedContent.GetType());
            Trace.WriteLine("myTabControl.SelectedItem    is " + myTabControl.SelectedItem.GetType());

            // do something with content of the selected tab:
            ///myTabControl.SelectedContent.Foreground = new SolidColorBrush(Color.FromRgb(255, 0, 0));
        }
    }    
}

主窗口.xaml:

    <Window x:Class="testTabControl.MainWindow"
            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
            xmlns:testTabControl="clr-namespace:testTabControl" 
            Title="MainWindow" Height="350" Width="525"
            SizeChanged="OnSizeChanged"
            >
        <Window.Resources>

            <DataTemplate x:Key="myContent" DataType="{x:Type testTabControl:Customer}">
                <TextBlock x:Name="myContentRoot">
                    This is the content for 
                    <TextBlock Text="{Binding FirstName}"/> <TextBlock Text="{Binding LastName}"/>
                </TextBlock>
            </DataTemplate>

            <DataTemplate x:Key="myHeader" DataType="{x:Type testTabControl:Customer}">
                <TextBlock Text="{Binding LastName}"/>
            </DataTemplate>

        </Window.Resources>

        <TabControl 
            x:Name="myTabControl" 
            SelectedIndex="0" 
            ItemTemplate="{StaticResource ResourceKey=myHeader}"
            ContentTemplate="{StaticResource ResourceKey=myContent}"
         />

    </Window>

在 OnSizeChanged 方法中，我希望 myTabControl.SelectedContent 返回从 DataTemplate 生成的 TextBlock。但是返回了一个 Customer 的实例!与 myTabControl.SelectedItem 相同。

我发现获取生成内容的唯一方法如下: http://msdn.microsoft.com/en-us/library/bb613579.aspx

有没有人知道没有可视化树行走的其他解决方案？

Answer 1

您的 TabControl包含类型 Customer 的对象. Templates可以用来告诉WPF如何绘制每个Customer对象，但是它不会改变 TabControl 中的项目的事实还在Customer对象。

如果您想访问该项目的模板化 UI 对象，您可以走 VisualTree或使用 ItemContainerGenerator获取装有 SelectedItem 的容器

例如，

var selectedItem = myTabControl.SelectedItem;

var selectedItemContainer = 
    myTabControl.ItemContainerGenerator.ContainerFromItem(selectedItem);