Question

需要在ComboBox选择更改的事件处理程序中执行深层复制 DeepCopy失败但完全相同的DeepCopy在ctor和Button Click中的事件处理程序中取得了成功在两台机器上复制了这个是否愿意更改处理程序或深层副本，但我非常需要它在ComboBox SelectionChanged的事件处理程序中

在代码

中查找失败

using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
using System.ComponentModel;

namespace DeepCopy
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        private List<TestClass> testClassList = new List<TestClass>();
        public MainWindow()
        {
            InitializeComponent();
            this.DataContext = this;
            try
            {
                TestClass tca = new TestClass();
                tca.Prop1 = "Tcaa";
                TestClass tcb = DeepClone<TestClass>(tca);
                tca.Prop1 = "TcaNew1";
                System.Diagnostics.Debug.WriteLine(tca.Prop1);
                System.Diagnostics.Debug.WriteLine(tcb.Prop1);
                tcb.Prop1 = "sdf1";
                System.Diagnostics.Debug.WriteLine(tcb.Prop1);
            }
            catch (Exception Ex)
            {
                System.Diagnostics.Debug.WriteLine(Ex.Message);
            }
            TestClass tc = new TestClass();
            tc.Prop1 = "tc1";
            testClassList.Add(tc);
            tc = new TestClass();
            tc.Prop1 = "tc2";
            testClassList.Add(tc);
            foreach (TestClass tcx in TestClassList)
            {
                try
                {
                    // this does not fail
                    TestClass tcb = DeepClone<TestClass>(tcx);
                    System.Diagnostics.Debug.WriteLine(tc.Prop1);
                    System.Diagnostics.Debug.WriteLine(tcb.Prop1);
                    tc.Prop1 += "ctorA";
                    System.Diagnostics.Debug.WriteLine(tc.Prop1);
                    System.Diagnostics.Debug.WriteLine(tcb.Prop1);
                    tcb.Prop1 += "ctorB";
                    System.Diagnostics.Debug.WriteLine(tcb.Prop1);
                }
                catch (Exception ex)
                {
                    System.Diagnostics.Debug.WriteLine(ex.Message);
                }
            }
        }
        public List<TestClass> TestClassList { get { return testClassList; } }
        [Serializable()]
        public abstract class TestAstract : INotifyPropertyChanged
        {
            public event PropertyChangedEventHandler PropertyChanged;
            protected void NotifyPropertyChanged(String info)
            {
                if (PropertyChanged != null)
                {
                    PropertyChanged(this, new PropertyChangedEventArgs(info));
                }
            }
            public abstract string Prop1 { get; set; }
        }
        [Serializable()]
        public class TestClass : TestAstract
        {            
            private string prop1;
            public override string Prop1 
            {
                get { return prop1; }
                set
                {
                    if (prop1 == value) return;
                    prop1 = value;
                    NotifyPropertyChanged("Prop1");
                }
            }
            public TestClass() { }
        }
        public static T DeepClone<T>(T obj)
        {
            using (var ms = new MemoryStream())
            {
                var formatter = new BinaryFormatter();
                formatter.Serialize(ms, obj);
                ms.Position = 0;

                return (T)formatter.Deserialize(ms);
            }
        }

        private void clickDeepCopy(object sender, RoutedEventArgs e)
        {
            foreach (TestClass tc in TestClassList)
            {
                try
                {
                    // this does not fail
                    TestClass tcb = DeepClone<TestClass>(tc);
                    System.Diagnostics.Debug.WriteLine(tc.Prop1);
                    System.Diagnostics.Debug.WriteLine(tcb.Prop1);
                    tc.Prop1 += "clickA";
                    System.Diagnostics.Debug.WriteLine(tc.Prop1);
                    System.Diagnostics.Debug.WriteLine(tcb.Prop1);
                    tcb.Prop1 += "clickB";
                    System.Diagnostics.Debug.WriteLine(tcb.Prop1);
                }
                catch (Exception ex)
                {
                    System.Diagnostics.Debug.WriteLine(ex.Message);
                }
            }
        }

        private void cbSelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            foreach (TestClass tc in TestClassList)
            {
                try
                {
                    // this fails
                    TestClass tcb = DeepClone<TestClass>(tc);
                    // A first chance exception of type 'System.Runtime.Serialization.SerializationException' occurred in mscorlib.dll
                    // Type 'System.ComponentModel.PropertyChangedEventManager' in Assembly 'WindowsBase, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' is not marked as serializable.
                    // A first chance exception of type 'System.Runtime.Serialization.SerializationException' occurred in mscorlib.dll
                    System.Diagnostics.Debug.WriteLine(tc.Prop1);
                    System.Diagnostics.Debug.WriteLine(tcb.Prop1);
                    tc.Prop1 += "cbceA";
                    System.Diagnostics.Debug.WriteLine(tc.Prop1);
                    System.Diagnostics.Debug.WriteLine(tcb.Prop1);
                    tcb.Prop1 = "cbceB";
                    System.Diagnostics.Debug.WriteLine(tcb.Prop1);
                }
                catch (Exception ex)
                {
                    System.Diagnostics.Debug.WriteLine(ex.Message);
                }
            }
        }
    }
}

<Window x:Class="DeepCopy.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">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>
        <Button Grid.Row="0" Content="DeepCopy" Click="clickDeepCopy" />
        <ComboBox Grid.Row="1" ItemsSource="{Binding Path=TestClassList}" DisplayMemberPath="Prop1" SelectionChanged="cbSelectionChanged" />
    </Grid>
</Window>

更有趣的是尝试了一个空的ComboBox SelectionChanged事件处理程序
在调用空的ComboBox SelectionChanged后，按钮单击将失败

在XAML中删除了ComboBox SelectionChanged事件处理程序在ComboBox SelectionChanged之后，按钮单击将失败 - 即使没有事件处理程序
但Button Click将在ComboBox SelectionChanged

之前成功

在XAML中删除了ComboBox SelectionChanged事件处理程序在XAML中设置SelectedIndex = 0 Button Click事件处理程序将在第一次失败

即使没有SelectionChanged事件处理程序而且ComboBox上没有SelectedIndex，仍然会在TestClassList上调用get 单独的原始绑定不会破坏深层复制在ComboBox上选择任何项目后，深层复制将中断

我知道你很怀疑，但我花了几个小时才知道这个

Answer 1

您需要在活动中添加[field：NonSerialized]

[field:NonSerialized]
public event PropertyChangedEventHandler PropertyChanged;

Answer 2

您需要禁用PropertyChanged事件的序列化（即，由于数据绑定，ComboBox等订阅者）。

看看这个类似的问题How do I ignore event subscribers when serializing an object?

DeepCopy在ComboBox SelectionChanged的事件处理程序上失败

2 个答案: