从 C# 访问 ListBox 的 ScrollViewer [英] Accessing the ScrollViewer of a ListBox from C#

问题描述

我想更改 C# 中 ListBox 的 ScrollViewer 的属性.

I'd like to change the properties of a ScrollViewer of a ListBox from C#.

我找到了 this question 在 Stackoverflow 上.我接受了接受的答案的建议，并将 ScrollViewer 作为子类的属性公开.但是，这在下面显示的示例中似乎不起作用.该问题中的一些评论也指出这种技术不起作用.

I found this question here on Stackoverflow. I took the accepted answer's advice and exposed the ScrollViewer as a property of a subclass. However, this doesn't appear to be working in an example shown below. Some of the comments in that question also state that this technique didn't work.

XAML:

<Window x:Class="StackoverflowListBoxScrollViewer.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">

</Window>

C#:

using System;
using System.Windows;
using System.Windows.Controls;

namespace StackoverflowListBoxScrollViewer
{
    public class MyListBox : ListBox
    {
        public ScrollViewer ScrollViewer
        { get { return (ScrollViewer)GetTemplateChild("ScrollViewer"); } }
    }

    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            var myListBox = new MyListBox();

            Content = myListBox;

            myListBox.Items.Add(new Button() { Content = "abc" });
            myListBox.Items.Add(new Button() { Content = "abc" });
            myListBox.Items.Add(new Button() { Content = "abc" });
            myListBox.Items.Add(new Button() { Content = "abc" });
            myListBox.Items.Add(new Button() { Content = "abc" });

            var button = new Button() { Content = "Check ScrollViewer" };
            button.Click += (s, e) =>
                {
                    if (myListBox.ScrollViewer == null)
                        Console.WriteLine("null");
                };
            myListBox.Items.Add(button);
        }
    }
}

当我点击Check ScrollViewer"按钮时，它会打印null".即，未检索到 ScrollViewer.

When I click the "Check ScrollViewer" button, it prints "null". I.e., the ScrollViewer wasn't retrieved.

我怎么去那个该死的ScrollViewer?:-)

How do I get to that darn ScrollViewer? :-)

推荐答案

如果您将使用标准 ListBox，那么您可以将您的 getter 更改为这个:

If you will use standard ListBox, so you can change yours getter to this one:

public class MyListBox : ListBox
{
    public ScrollViewer ScrollViewer
    {
        get 
        {
            Border border = (Border)VisualTreeHelper.GetChild(this, 0);

            return (ScrollViewer)VisualTreeHelper.GetChild(border, 0);
        }
    }
}

这篇关于从 C# 访问 ListBox 的 ScrollViewer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！