c# - Xamarin 表单 - 切换条目 View 的 IsPassword 时出错(仅在 uwp 上)

Question

我有以下示例应用程序代码:

App.cs(入口点)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using Xamarin.Forms;

namespace App1
{
    public class ListItem
    {
        public string ItemText { get; set; }
        public string ItemDetail { get; set; }
        public string Password { get; set; }
    }


    public class App : Application
    {
        public App()
        {
            // The root page of your application
            var listView = new ListView
            {
                ItemTemplate = new DataTemplate(() =>
                {
                    var textCell = new TextCell();
                    textCell.SetBinding(TextCell.TextProperty, "ItemText");
                    textCell.SetBinding(TextCell.DetailProperty, "ItemDetail");
                    return textCell;
                }),
                VerticalOptions = LayoutOptions.FillAndExpand,
                ItemsSource = new List<ListItem>
                {
                    new ListItem
                    {
                        ItemText = "Item 1",
                        ItemDetail = "Detail 1",
                        Password = "123456"
                    },

                    new ListItem
                    {
                        ItemText = "Item 2",
                        ItemDetail = "Detail 2",
                        Password = "76432"
                    },
                    new ListItem
                    {
                        ItemText = "Item 3",
                        ItemDetail = "Detail 3",
                        Password = "66543"
                    },
                }
            };

            listView.ItemTapped += ListView_ItemTapped;

            var content = new ContentPage
            {
                Title = "App1",
                Content = new StackLayout
                {
                    VerticalOptions = LayoutOptions.Center,
                    Children =
                    {
                        new ScrollView
                        {
                            Content = new StackLayout
                            {
                                Padding = 10,
                                Children =
                                {
                                    listView
                                }
                            }
                        }
                    }
                }
            };

            MainPage = new NavigationPage(content);
        }

        private async void ListView_ItemTapped(object sender, ItemTappedEventArgs e)
        {
            await this.MainPage.Navigation.PushAsync(new PasswordPage((e.Item as ListItem).Password));
        }

        protected override void OnStart()
        {
            // Handle when your app starts
        }

        protected override void OnSleep()
        {
            // Handle when your app sleeps
        }

        protected override void OnResume()
        {
            // Handle when your app resumes
        }
    }
}

密码页面.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection.Emit;
using System.Text;

using Xamarin.Forms;

namespace App1
{
    public class PasswordPage : ContentPage
    {
        private string Password;
        private Entry PasswordEntry = new Entry();

        public PasswordPage(string password)
        {
            this.Password = password;
            PasswordEntry.IsPassword = true;
            PasswordEntry.Text = password;

            var button = new Button();
            button.Text = "Show/Hide";
            button.Clicked += Button_Clicked;

            Content = new StackLayout
            {
                Children = {
                    new Label { Text = "Password" },
                    PasswordEntry,
                    button
                }
            };
        }

        private void Button_Clicked(object sender, EventArgs e)
        {
            PasswordEntry.IsPassword = !PasswordEntry.IsPassword;
        }
    }
}

我在以下场景中收到以下错误，仅在 UWP 上(您可以 download 附加的示例项目，运行 UWP 项目并按照指南进行重现):

1. 在应用程序主页面上，单击 ListView 的任意项目。
2. 在打开的页面上，点击“显示/隐藏”按钮两次。
3. 返回上一页。
4. 再次单击 ListView 的任意项目。

此错误仅在 UWP/Windows 上发生，并且仅当您切换“条目” View 的“IsPassword”属性时才会发生。如果单击“显示/隐藏”一次，则不会出现错误。

错误:

System.ArgumentException

The parameter is incorrect.

E_RUNTIME_SETVALUE

at Windows.UI.Xaml.DependencyObject.SetValue(DependencyProperty dp, Object value) at Xamarin.Forms.Platform.UWP.EntryRenderer.UpdateIsPassword() at Xamarin.Forms.Platform.UWP.EntryRenderer.OnElementChanged(ElementChangedEventArgs'1 e) at Xamarin.Forms.Platform.UWP.VisualElementRenderer'2.SetElement(VisualElement element) at Xamarin.Forms.Platform.UWP.Platform.CreateRenderer(VisualElement element) at Xamarin.Forms.Platform.UWP.VisualElementPackager.OnChildAdded(Object sender, ElementEventArgs e) at Xamarin.Forms.Platform.UWP.VisualElementPackager.Load() at Xamarin.Forms.Platform.UWP.VisualElementRenderer'2.SetElement(VisualElement element) at Xamarin.Forms.Platform.UWP.Platform.CreateRenderer(VisualElement element) at Xamarin.Forms.Platform.UWP.VisualElementPackager.OnChildAdded(Object sender, ElementEventArgs e) at Xamarin.Forms.Platform.UWP.VisualElementPackager.Load() at Xamarin.Forms.Platform.UWP.VisualElementRenderer'2.SetElement(VisualElement element) at Xamarin.Forms.Platform.UWP.Platform.CreateRenderer(VisualElement element) at Xamarin.Forms.Platform.UWP.VisualElementExtensions.GetOrCreateRenderer(VisualElement self) at Xamarin.Forms.Platform.UWP.NavigationPageRenderer.SetPage(Page page, Boolean isAnimated, Boolean isPopping) at Xamarin.Forms.Platform.UWP.NavigationPageRenderer.OnPushRequested(Object sender, NavigationRequestedEventArgs e) at Xamarin.Forms.NavigationPage.d__90.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Xamarin.Forms.NavigationPage.d__48.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult()
at App1.App.d__1.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.AsyncMethodBuilderCore.<>c.b__6_0(Object state) at System.Threading.WinRTSynchronizationContext.Invoker.InvokeCore()

Download Project Sample

Answer 1

看起来这实际上是 Forms 中的一个错误。我已经提交了一份错误报告 here .

该问题似乎与设置 native TextBox 控件的 InputScope 属性有关。我创建了一个pull request寻求修复，希望尽快合并并发布。