向数据库插入新记录时，WPF MVVM ListView未更新

Question

我在WPF MVVM应用程序中的ListView遇到了一点小问题。我的项目使用带有Dapper-Contrib的Sqlite数据库文件。我可以成功添加新员工，但之后我的ListView不会更新。

我的代码看起来像这样: SqlRepository.cs (泛型函数)

public IList<TEntity> GetAll()
{
    return DbContext.Connection.GetAll<TEntity>().ToList();
}

ISqlRepository.cs (接口)

IList<TEntity> GetAll();

EmployeeViewModel.cs (我的主视图的ViewModel)

using Autofac;
using AutoMapper;
using Calendar.Commands;
using Calendar.Database.Entities;
using Calendar.Database.Repositories;
using Calendar.Models;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Windows;

namespace Calendar.ViewModels
{
    internal class EmployeeViewModel : ViewModelBase
    {
        private RelayCommand command;
        ObservableCollection<EmployeeEntity> m_lstEmployees = new ObservableCollection<EmployeeEntity>();
        /// <summary>
        /// Initializes a new instance of the EmployeeViewModel class.
        /// </summary>
        public EmployeeViewModel()
        {
            employee = new Employee();

        }
        public Employee employee
        {
            get;
            set;
        }
        public RelayCommand AddNewEmployee
        {
            get
            {
                this.command = new RelayCommand(SaveChanges);
                return this.command;
            }
        }
        public void SaveChanges()
        {
            var container = ContainerConfig.Configure();
            using (var scope = container.BeginLifetimeScope())
            {
                var test = scope.Resolve<IEmployeeRepository>();
                employee.FirstName = this.employee.FirstName;
                employee.LastName = this.employee.LastName;
                var config = new MapperConfiguration(cfg => cfg.CreateMap<Employee, EmployeeEntity>());
                var mapper = config.CreateMapper();
                var test99 = mapper.Map<EmployeeEntity>(employee);
                test.Add(test99);
            }
        }
        public ObservableCollection<EmployeeEntity> EmployeeList
        {
            get
            {
                var container = ContainerConfig.Configure();
                using (var scope = container.BeginLifetimeScope())
                {
                    var test = scope.Resolve<IEmployeeRepository>();
                    IList<EmployeeEntity> gugus = test.GetAll();
                    foreach (var item in gugus)
                    m_lstEmployees.Add(item);
                }
                return m_lstEmployees;
            }
        }
    }
}

MainWindow.xaml

<ListView ItemsSource="{Binding EmployeeList, UpdateSourceTrigger=PropertyChanged}">
            <ListView.View>
                <GridView>
                    <GridViewColumn Header="FirstName" DisplayMemberBinding="{Binding FirstName}"/>
                    <GridViewColumn Header="LastName" DisplayMemberBinding="{Binding LastName}"/>
                </GridView>
            </ListView.View>
        </ListView>

我知道我需要一个ObservableCollection，这样PropertyChanged才能触发(EmployeeViewModel继承了包含InotifyPropertyChanged内容的ViewModelBase )。

在我的数据库中添加新条目时，似乎没有“反馈”。我错过了什么？

Answer 1

尝试在将更改保存到数据库后调用OnPropertyChanged(nameof(EmployeeList)) (可能在SaveChanges()方法中)。XAML标记需要知道何时重新计算列表视图ItemSource绑定中的EmployeeList。我所说的OnPropertyChanged是指ViewModelBase中的一个方法，它从INotifyPropertyChanged调用PropertyChanged事件(您可以使用不同的名称)。