Question

在DataGrid中使用DataGridCheckBoxColumn并将其绑定到支持模型中的布尔属性时，会发生这种情况。单击该列并选中/未选中复选框时，它的行为符合预期。但是，当我关闭主窗口时，将引发异常。仅使用文本列并与之交互时不会发生这种情况。如果我根本不与复选框列交互，而只是关闭窗口，也不会发生这种情况。只有在与复选框列进行交互之后关闭窗口时，才会发生这种情况。

开发环境：

操作系统：
1. Arch Linux，Gnome 3和Wayland。
2. Windows 10专业版

开发：
dotnet核心3.1.103
IDE：VS代码

复制步骤：

使用DataGrid的常规过程是本教程文章中提到的： Avalonia DataGrid Getting Started

我对本文所做的唯一更改是将DataGridCheckBoxColumn添加到DataGrid，并将布尔IsChecked布尔属性添加到本教程中使用的“ Person”模型类中-然后将两者绑定在一起。

因此关键步骤是：

$ dotnet new avalonia.mvvm
在* csproj文件中，将所有Avalonia包含的版本都替换为0.9.10，因为那是我正在使用的DataGrid的版本。
$ dotnet add package Avalonia.Controls.DataGrid
在App.xaml中，添加样式：
<StyleInclude Source="avares://Avalonia.Controls.DataGrid/Themes/Default.xaml"/>
将以下属性添加到模型类“ Person” ---其余代码保持不变，并按照链接的教程进行操作：

 public bool IsChecked
        {get;set;}

将DataGridCheckBoxColumn添加到DataGrid并按如下所示进行绑定（其余的列保持不变，并按照链接的教程进行操作）：

<DataGrid.Columns>
        <DataGridTextColumn Header="First Name" 
                            Binding="{Binding FirstName}" 
                            Width="2*" />
        <DataGridTextColumn Header="Last Name" 
                            Binding="{Binding LastName}" 
                            Width="2*" />
        <DataGridTextColumn Header="Department" 
                            Binding="{Binding DepartmentNumber}" 
                            Width="*" />

        <DataGridCheckBoxColumn Header="IsChecked" 
                            Binding="{Binding IsChecked}" 
                            Width="*" />

    </DataGrid.Columns>

然后，当我运行应用程序（从命令行或vscode）时-GUI按预期显示-带有所有列和值-并通常显示其他复选框列。 __ 当我单击复选框列时-复选框确实按预期方式被选中和取消选中（尽管需要额外单击一次）。 但是当我通过单击右上角的“ X”关闭窗口时-那是未处理的异常发生的时间-不在此之前。

完整的例外文本：

未处理的异常。 System.InvalidOperationException：集合已被修改；枚举操作可能无法执行。在System.Collections.Generic.List`1.Enumerator.MoveNextRare（）处在Avalonia.Collections.AvaloniaList`1.Enumerator.MoveNext（）在System.Linq.Enumerable.OfTypeIterator [TResult]（IEnumerable源）+ MoveNext（）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Visual.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Input.InputElement.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.Control.OnDetachedFromVisualTreeCore（VisualTreeAttachmentEventArgs e）在Avalonia.Controls.TopLevel.HandleClosed（）在Avalonia.Controls.WindowBase.HandleClosed（）在Avalonia.Controls.Window.HandleClosed（）在Avalonia.X11.X11Window.Cleanup（）在Avalonia.X11.X11Window.Dispose（）在Avalonia.X11.X11Window.OnEventSync（XEvent ev）在Avalonia.X11.X11Window.OnEvent（XEvent ev）在Avalonia.X11.X11PlatformThreading.HandleX11（CancellationToken cancelleToken）在Avalonia.X11.X11PlatformThreading.RunLoop（CancellationToken cancelleToken）在Avalonia.Threading.Dispatcher.MainLoop（CancellationToken cancelleToken）在Avalonia.Controls.ApplicationLifetimes.ClassicDesktopStyleApplicationLifetime.Start（String [] args）在Avalonia.ClassicDesktopStyleApplicationLifetimeExtensions.StartWithClassicDesktopLifetime [T]（T builder，String [] args，ShutdownMode shutdownMode）在/home/[myusername]/[pathtoproject]/Program.cs:line 14中的d3.Program.Main（String [] args）

Person类的代码：

public class Person
    {
        public int DepartmentNumber { get; set; }

        public string DeskLocation{ get; set; }

        public int EmployeeNumber { get; set; }

        public string FirstName { get; set; }

        public string LastName { get; set; }

        public bool IsChecked
        {get;set;}
    }

MainWindowViewModel的代码，充当MainWindow的代码，并使用上面的Person类托管ObservableCollection并将其公开为名为People的公共属性。 DataGrid绑定到此People属性，该属性用作Person类的集合（其属性由不同的列表示，例如DataGridTextColumn和DataGridCheckBoxColumn）：

public class MainWindowViewModel : ViewModelBase
    {
        public ObservableCollection<Person> People { get; set;}

        public MainWindowViewModel()
        {
            People = new ObservableCollection<Person>(GenerateMockPeopleTable());
        }

        private ObservableCollection<Person> GenerateMockPeopleTable()
        {
            var defaultPeople = new ObservableCollection<Person>()
            {
                new Person()
                {
                    FirstName = "Pat", 
                    LastName = "Patterson", 
                    EmployeeNumber = 1010,
                    DepartmentNumber = 100, 
                    DeskLocation = "B3F3R5T7",
                    IsChecked = false
                },
                new Person()
                {
                    FirstName = "Jean", 
                    LastName = "Jones", 
                    EmployeeNumber = 973,
                    DepartmentNumber = 200, 
                    DeskLocation = "B1F1R2T3",
                    IsChecked = true
                },
                new Person()
                {
                    FirstName = "Terry", 
                    LastName = "Tompson", 
                    EmployeeNumber = 300,
                    DepartmentNumber = 100, 
                    DeskLocation = "B3F2R10T1",
                    IsChecked = false
                }
            };

            return defaultPeople;
        }
    }

更新：我已放弃寻找解决方案。这是我的解决方法：

而不是使用DataGridCheckBoxColumn（它也具有仅在单击两次时才被检查的额外烦恼-我正在使用DataGridTemplateColumn。它解决了上面的异常问题-以及我希望的属性可以在单击。

<DataGridTemplateColumn Header="Select Todo">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <CheckBox IsChecked="{Binding IsChecked}"/>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>

Answer 1

我认为您的问题与所使用的收藏有关，而不是复选框。您必须在收集后致电.ToList()。请检查以下链接： Collection was modified; enumeration operation may not execute

Answer 2

将GenerateMockPeopleTable()替换为GenerateMockPeopleTable().ToList()，然后检查问题是否解决。

DataGridCheckBoxColumn的用法-引发未处理的异常

2 个答案: