如何在ControlTemplate中声明事件处理程序？

Question

我有以下内容ControlTemplate:

<ControlTemplate>
    <Grid VerticalAlignment="Stretch" HorizontalAlignment="Left" Width="400">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="18" />
            <ColumnDefinition Width="20*" />
            <ColumnDefinition Width="20*" />
            <ColumnDefinition Width="20*" />
            <ColumnDefinition Width="45" />
        </Grid.ColumnDefinitions>
        <TextBox Grid.Column="1" Template="{StaticResource watermark}" HorizontalAlignment="Stretch" Margin="4,0,0,4" Tag="Number" />
        <TextBox Grid.Column="2" Template="{StaticResource watermark}" HorizontalAlignment="Stretch" Margin="4,0,0,4" Tag="Login" />
        <TextBox Grid.Column="3" Template="{StaticResource watermark}" HorizontalAlignment="Stretch" Margin="4,0,0,4" Tag="Password" />
        <Button Grid.Column="4" HorizontalAlignment="Stretch" Content="Add" Margin="4,0,0,4" Click="AddUser_Click"/>
    </Grid>
</ControlTemplate>

我该怎么写AddUser_Click才能访问文本框Text属性？

upd:只是为了说清楚.我知道如何在Click这里连接事件处理程序.问题是如何阅读其中的文本框内容,因为我不能给它们起名,因为它们在模板中.

Answer 1

你可以做的是给Button一个名字"PART_Button".然后在控件中重写OnApplyTemplate方法.在代码中,你可以做到

var btn = this.Template.FindName("PART_Button", this) as Button;
btn.Click += ...

Answer 2

在x:Class当前文件的指令指向的类中搜索事件处理程序,这允许您内联添加事件处理程序而无需覆盖该类并覆盖OnApplyTemplate添加处理程序的麻烦,无论您声明ControlTemplate的位置如何.

MainWindow.xaml:

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
  <Button Content="asdf">
    <Button.Style>
      <Style TargetType="Button">
        <Setter Property="Template">
          <Setter.Value>
            <ControlTemplate TargetType="Button">
              <Button Content="{TemplateBinding Content}" Click="Button_Click"/>
            </ControlTemplate>
          </Setter.Value>
        </Setter>
      </Style>
    </Button.Style>
  </Button>
</Window>

MainWindow.xaml.cs:

using System.Windows;
namespace WpfApplication1
{
  /// <summary>
  /// Interaction logic for MainWindow.xaml
  /// </summary>
  public partial class MainWindow : Window
  {
    public MainWindow()
    {
      InitializeComponent();
    }

    private void Button_Click(object sender, RoutedEventArgs e)
    {
      MessageBox.Show("Button clicked!");
    }
  }
}

Answer 3

如果您有权访问 templatedparent（SelectedItem、FindVisualParent 等），则可以在将名称应用于文本框时执行此操作。例如，ControlTemplate 用于 ComboBoxItem。

private void AddUser_Click(object sender, RoutedEventArgs e)
{
    ComboBoxItem comboBoxItem = GetVisualParent<ComboBoxItem>(button);
    TextBox textBox = comboBoxItem.Template.FindName("numberTextBox", comboBoxItem) as TextBox;
    //...
}

获取 ControlTemplate 中的文本框的另一种方法是使用可视化树。像这样的东西

private void AddUser_Click(object sender, RoutedEventArgs e)
{
    Button button = sender as Button;
    Grid parentGrid = GetVisualParent<Grid>(button);
    List<TextBox> textBoxes = GetVisualChildCollection<TextBox>(parentGrid);
    foreach (TextBox textBox in textBoxes)
    {
        if (textBox.Tag == "Number")
        {
            // Do something..
        }
        else if (textBox.Tag == "Login")
        {
            // Do something..
        }
        else if (textBox.Tag == "Password")
        {
            // Do something..
        }
    }
}

以及 GetVisualParent 和 GetVisualChildCollection 的实现

public static T GetVisualParent<T>(object childObject) where T : Visual
{
    DependencyObject child = childObject as DependencyObject;
    // iteratively traverse the visual tree
    while ((child != null) && !(child is T))
    {
        child = VisualTreeHelper.GetParent(child);
    }
    return child as T;
}

public static List<T> GetVisualChildCollection<T>(object parent) where T : Visual
{
    List<T> visualCollection = new List<T>();
    GetVisualChildCollection(parent as DependencyObject, visualCollection);
    return visualCollection;
}
private static void GetVisualChildCollection<T>(DependencyObject parent, List<T> visualCollection) where T : Visual
{
    int count = VisualTreeHelper.GetChildrenCount(parent);
    for (int i = 0; i < count; i++)
    {
        DependencyObject child = VisualTreeHelper.GetChild(parent, i);
        if (child is T)
        {
            visualCollection.Add(child as T);
        }
        else if (child != null)
        {
            GetVisualChildCollection(child, visualCollection);
        }
    }
}