C#基础（三十五） ListView绑定ObservableCollection集合:增加、删除元素时UI会更新，修改属性时不会更新。

一、简介

 问题描述：

        ListView绑定ObservableCollection:增加、删除元素时UI会更新，修改属性时不会更新。相信大家都遇到过类似的问题。

绑定如下：

      <!--列表 -->
                <Grid Grid.Column="1" Margin="4,8,7,-1">
                    <ListView Grid.Row="1" Grid.Column="1" Style="{StaticResource ListViewStyle1}" Name="listview_User" ItemContainerStyle="{StaticResource ListViewItemContainerStyle}" ItemsSource="{Binding AccountList,Mode=TwoWay}" SelectedIndex="{Binding SelectIndex}">
                        <i:Interaction.Triggers>
                            <!--加载-->
                            <i:EventTrigger EventName="Loaded">
                                <i:InvokeCommandAction Command="{Binding LoadedCommand}"/>
                            </i:EventTrigger>

                            <!--选中-->
                            <i:EventTrigger EventName="SelectionChanged">
                                <!--<prism:InvokeCommandAction Command="{Binding ListViewSelectedCommand}" CommandParameter="{Binding SelectedItems, ElementName=lvPatientList}" />-->
                                <prism:InvokeCommandAction Command="{Binding ListViewSelectedCommand}"/>
                            </i:EventTrigger>
                        </i:Interaction.Triggers>

              
                        
                        <ListView.View>
                            <GridView ColumnHeaderContainerStyle="{StaticResource DefaultGridViewColumnHeader}">
                                <GridViewColumn Header="账户名" Width="290" DisplayMemberBinding="{Binding AccountListName,Mode=TwoWay}"/>
                                <GridViewColumn Header="账户描述" Width="290" DisplayMemberBinding="{Binding AccountListdescription,Mode=TwoWay}"/>
                                <!--<GridViewColumn Header="账户类型" Width="290" DisplayMemberBinding="{Binding ElementName=cbb_uerLevel,Path=SelectedItem}"/>-->
                                <GridViewColumn Header="账户类型" Width="290" DisplayMemberBinding="{Binding AccountListPassWord,Mode=TwoWay}"/>
                                <GridViewColumn Header="指纹登记" Width="290" DisplayMemberBinding="{Binding AccountListFingerID,Mode=TwoWay}"/>
                                <GridViewColumn Header="人脸登记" Width="290" DisplayMemberBinding="{Binding AccountListFaceID,Mode=TwoWay}"/>
                            </GridView>
                        </ListView.View>
                    </ListView>
                </Grid>

集合如下：

       private ObservableCollection<AccountList> _accountList = new ObservableCollection<AccountList>();
        /// <summary>
        ///账户列表
        /// </summary>
        public ObservableCollection<AccountList> AccountList
        {
            get { return _accountList; }
            set { SetProperty(ref _accountList, value); }
        }

修改函数如下：

 /// <summary>
        /// 修改用户信息
        /// </summary>
        private void ModifyCommandFunc()
        {
            try
            {
                if (SelectIndex == -1)
                {
                    EMessageBox.Show("请选择一位需要编辑的账户！", "", EMessageBoxButton.OK, EMessageBoxImage.Warning);
                    return;
                }

                if (SelectIndex > -1)//if (SelectIndex >= 0)
                {
                    _accountList[SelectIndex].AccountListName = UserName;
                    _accountList[SelectIndex].AccountListdescription = Userdescription;
                    _accountList[SelectIndex].AccountListPassWord = UserPassWord;
                    _accountList[SelectIndex].AccountListFingerID = AccountFingerID;
                    _accountList[SelectIndex].AccountListFaceID = AccountFaceID;
                    //Expression<Func<PatientInfo, bool>> QueryConditionsExpression1 = u => string.IsNullOrEmpty(SearchBoxContent) || u.StudyId.ToString().Contains(SearchBoxContent) || u.PatientId.Contains(SearchBoxContent) || u.PatientName.Equals(SearchBoxContent);
                    //Expression<Func<PatientInfo, bool>> QueryConditionsExpression2 = u => string.IsNullOrEmpty(null);
                    //operateDataSheet.SearchFunc(strSearchTable, SelectIndex, QueryConditionsExpression1, QueryConditionsExpression2);
                    //PreviewList = new ObservableCollection<SeriesInfoListViewModel>(operateDataSheet.GetPreviewListFunc());
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("UserInfoConfigViewModel.cs::ModifyCommandFunc()配置页账户列表修改发生失败--" + ex.ToString());
                LogHelper.Error("UserInfoConfigViewModel.cs::ModifyCommandFunc()配置页账户列表修改发生失败--" + ex.Message);
            }
        }

二、本质原因

   参考 https://bbs.youkuaiyun.com/topics/390560251

       ObservableCollection<Object> 中的Object类继承接口INotifyPropertyChanged 才行，这样就可以直接用集合加下标来自动更新listview了。

二、解决方法

方法1：AccountList直接继承接口INotifyPropertyChanged

参考https://blog.youkuaiyun.com/qq182477985/article/details/80617533

class ViewListItem : INotifyPropertyChanged
    {
        public string name { get; set; }
        
        private string _status;
        
        public string status {
            get
            {
                return _status;
            }
            set
            {
                _status = value;
                if( PropertyChanged != null)
                {
                    PropertyChanged(this, new PropertyChangedEventArgs("status"));
                }
            }
        }
        public event PropertyChangedEventHandler PropertyChanged;
    }
}

方法2：Prism架构中，AccountList直接继承类BindableBase即可

    public class AccountList : BindableBase
    {

        private string _accountListName = null;
        /// <summary>
        ///账户列表
        /// </summary>
        public string AccountListName
        {
            get { return _accountListName; }
            set { SetProperty(ref _accountListName, value); }
        }
}

但是，如果你写成了下面的这种方式，属性就不会自动跟新：

    public class AccountList : BindableBase
    {

        /// <summary>
        /// 账户姓名
        /// </summary>
        public string AccountListName
        {
            get;
            set;
        }
   }

事件上，类BindableBase本质上也继承了INotifyPropertyChanged