我试图在我的“StateContainer”(帕特里克McCurley ) MAUI应用程序中实现.NET。当ListView第一次显示时，它正确工作。但是，在我滑动屏幕之前，当状态再次发生变化时，ListView不会显示。
当我添加任何视图元素(标签、按钮等)时对于包含ListView的视图，它不会出现。但是，当我使用任何其他视图元素将ListView移动到网格时，StateContainer将正确显示。如果网格不包含StateContainer以外的其他元素，则StateContainer无法正确显示。
我不知道这里出了什么问题。对于我来说，带有其他视图元素的网格并不是解决方案，因为我的页面不应该包含任何其他元素，比如StateContainer。
下面是一个再现问题的示例：
我很抱歉有很多代码:)我不知道问题出在哪里。
States.cs
代码语言：javascript运行复制public enum States
{
Loading,
Success
}StateCondition.cs
代码语言：javascript运行复制[ContentProperty("Content")]
public class StateCondition : View
{
public object State { get; set; }
public View Content { get; set; }
}StateContainer.cs
代码语言：javascript运行复制[ContentProperty("Conditions")]
public class StateContainer : ContentView
{
public List
public static readonly BindableProperty StateProperty =
BindableProperty.Create(nameof(State), typeof(object), typeof(StateContainer), null, BindingMode.Default, null, StateChanged);
private static void StateChanged(BindableObject bindable, object oldValue, object newValue)
{
var parent = bindable as StateContainer;
if (parent != null)
parent.ChooseStateProperty(newValue);
}
public object State
{
get { return GetValue(StateProperty); }
set { SetValue(StateProperty, value); }
}
private void ChooseStateProperty(object newValue)
{
if (Conditions == null && Conditions?.Count == 0) return;
var stateCondition = Conditions
.FirstOrDefault(condition =>
condition.State != null &&
condition.State.ToString().Equals(newValue.ToString()));
if (stateCondition == null) return;
Content = stateCondition.Content;
}
}MainPage.xaml
代码语言：javascript运行复制
MainPage.xaml.cs
代码语言：javascript运行复制public partial class MainPage : ContentPage
{
private States _state;
private int[] _someData;
public MainPage()
{
InitializeComponent();
this.BindingContext = this;
SomeData = new[] { 1, 2, 3, 4, 5 };
State = States.Success;
// it can be executed from outside the page
_ = Task.Run(ExecuteSomeWorkAsync);
}
public States State
{
get => _state;
private set
{
if (_state != value)
{
_state = value;
OnPropertyChanged();
}
}
}
public int[] SomeData
{
get => _someData;
private set
{
if (_someData != value)
{
_someData = value;
OnPropertyChanged();
}
}
}
public async Task ExecuteSomeWorkAsync()
{
await Task.Delay(2000);
State = States.Loading;
await Task.Delay(2000);
// generate new data for displaying
Random rnd = new();
var data = Enumerable.Range(0, 5).Select(n => rnd.Next(0, 5)).ToArray();
SomeData = data;
State = States.Success;
}
}