我有一个包含 10 个元素的字符串列表。我需要将 10 个中的 3 个元素随机添加到 C# 中的 WPF 列表框（每行一个元素）中

Question

    List<string> topLevel = new List<string>();
            

            topLevel.Add("000");
            topLevel.Add("100");
            topLevel.Add("200");
            topLevel.Add("300");
            topLevel.Add("400");
            topLevel.Add("500");
            topLevel.Add("600");
            topLevel.Add("700");
            topLevel.Add("800");
            topLevel.Add("900");

我试过了

  var random=  topLevel.Distinct().OrderBy(x => Guid.NewGuid()).Take(3);
            lst2.Items.AddRange(random.ToArray());

但是我得到一个“AddRange”作为带下划线的错误，我不知道如何修复它

Answer 1

例子：

    // Initial list source of values
    // This MUST be an observable collection
    private readonly ObservableCollection<string> lst2Source
        = new ObservableCollection<string>() { "1", "2" };

    // Immutable list of adding values
    private readonly ReadOnlyCollection<string> topLevel
        = Array.AsReadOnly("000 100 200 300 400 500 600 700 800 900".Split());

    public SomeWindow()
    {
        InitializeComponent();

        // Source is assigned once after XAML initialization
        lst2.ItemsSource = lst2Source;
    }

    private readonly Random random = new Random();
    private void AddRandom(int count)
    {
        topLevel
            .OrderBy(_ => random.Next())
            .Take(count)
            .ToList()
            .ForEach(level => lst2Source.Add(level)); // Elements are added not to the UI element, but to the value source
    }