WPF-DataGrid的增删查改

背景：该功能为几乎所有系统开发都需要使用的功能，现提供简单的案例。

1、MyCommand

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;

namespace WpfApplication25_DataGrid.ViewModels
{
    public class MyCommand:ICommand
    {
        private readonly Action _execute;
        private readonly Func<bool> _canExecute;

        private readonly Action<object> _execute2;


        public MyCommand(Action execute, Func<bool> canExecute = null)
        {
            _execute = execute;// throw new ArgumentNullException(nameof(execute));
            _canExecute = canExecute;
        }

        public event EventHandler CanExecuteChanged
        {
            add { CommandManager.RequerySuggested += value; }
            remove { CommandManager.RequerySuggested -= value; }
        }

        public bool CanExecute(object parameter)
        {
            return _canExecute == null || _canExecute();
        }

        public void Execute(object parameter)
        {
            _execute();

        }



    }
}

2、Notify

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;

namespace WpfApplication25_DataGrid.ViewModels
{
    public abstract class Notify : INotifyPropertyChanged
    {

        public event PropertyChangedEventHandler PropertyChanged;

        public void OnPropertyChanged([CallerMemberName] string name = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
        }

    }
}

3、数据模型Person

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

namespace WpfApplication25_DataGrid.Models
{
    public class Person
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public int Age { get; set; }
    }
}

4、编辑EditPersonWindow.xaml

<Window x:Class="WpfApplication25_DataGrid.Views.EditPersonWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApplication25_DataGrid.Views"
        mc:Ignorable="d"
        Title="EditPersonWindow" Height="200" Width="300">
    <Grid>
        <StackPanel Orientation="Vertical" Margin="10">
            <Label Content="姓名:"/>
            <TextBox Text="{Binding Person.Name}" Width="200"/>
            <Label Content="年龄:"/>
            <TextBox Text="{Binding Person.Age}" Width="200"/>
            <StackPanel Orientation="Horizontal" HorizontalAlignment="Right" Margin="0,10,0,0">
                <Button Content="保存" Command="{Binding SaveCommand}" Width="80"/>
                <Button Content="取消" Command="{Binding CancelCommand}" Width="80"/>
            </StackPanel>
        </StackPanel>
    </Grid>
</Window>

5、编辑EditPersonWindow.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using WpfApplication25_DataGrid.ViewModels;

namespace WpfApplication25_DataGrid.Views
{
    /// <summary>
    /// EditPersonWindow.xaml 的交互逻辑
    /// </summary>
    public partial class EditPersonWindow : Window
    {
        public EditPersonWindow(EditPersonViewModel viewModel)
        {
            InitializeComponent();
            this.DataContext = viewModel;
        }

    }
}

6、EditPersonViewModel.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;
using WpfApplication25_DataGrid.Models;

namespace WpfApplication25_DataGrid.ViewModels
{
    public class EditPersonViewModel : Notify
    {
        public Person Person { get; set; }
        public Action<bool?> CloseAction { get; set; }

        public MyCommand SaveCommand { get; set; }
        public MyCommand CancelCommand { get; set; }

        public EditPersonViewModel(Person person)
        {
            Person = person;
            SaveCommand = new MyCommand(SavePerson);
            CancelCommand = new MyCommand(Cancel);
        }



        private void SavePerson()
        {
            CloseAction?.Invoke(true);
        }

        private void Cancel()
        {
            CloseAction?.Invoke(false);
        }

    
    }
}

7、MainWindow.xaml

<Window x:Class="WpfApplication25_DataGrid.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApplication25_DataGrid"
        xmlns:vm="clr-namespace:WpfApplication25_DataGrid.ViewModels"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">

    <Grid>
        <DataGrid ItemsSource="{Binding Persons}"
                  SelectedItem="{Binding SelectedPerson}"
                  AutoGenerateColumns="False"
                  HorizontalAlignment="Left" Margin="10,10,0,0" VerticalAlignment="Top" Height="200" Width="507">
            <DataGrid.Columns>
                <DataGridTextColumn Header="ID" Binding="{Binding Id}" />
                <DataGridTextColumn Header="姓名" Binding="{Binding Name}" />
                <DataGridTextColumn Header="年龄" Binding="{Binding Age}" />
            </DataGrid.Columns>
        </DataGrid>
        <StackPanel Orientation="Horizontal" HorizontalAlignment="Left" Margin="10,220,0,0" VerticalAlignment="Top">
            <Button Content="新增" Command="{Binding AddCommand}" Width="80"/>
            <Button Content="删除" Command="{Binding DeleteCommand}" Width="80"/>
            <Button Content="修改" Command="{Binding UpdateCommand}" Width="80"/>
            <Button Content="搜索" Command="{Binding SearchCommand}" Width="80"/>
            <TextBox Text="{Binding SelectTxt}" Width="100" Margin="10,0,0,0"
                     HorizontalAlignment="Left" VerticalAlignment="Center"
                     />
        </StackPanel>
    </Grid>
</Window>

8.PersonViewModel.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Input;

using WpfApplication25_DataGrid.Models;
using WpfApplication25_DataGrid.Views;

namespace WpfApplication25_DataGrid.ViewModels
{

    public class PersonViewModel : Notify
    {
        public ObservableCollection<Person> Persons { get; set; }
        public Person SelectedPerson { get; set; }

        public ICommand AddCommand { get; set; }
        public ICommand DeleteCommand { get; set; }
        public ICommand UpdateCommand { get; set; }
        public ICommand SearchCommand { get; set; }

        /// <summary>
        /// 查询字段
        /// </summary>
        private string selectTxt = "未登录";
        public string SelectTxt
        {
            get { return selectTxt; }
            set
            {
                selectTxt = value;
                OnPropertyChanged();
            }
        }


        public PersonViewModel()
        {
            Persons = new ObservableCollection<Person>
            {
                new Person { Id = 1, Name = "Alice", Age = 25 },
                new Person { Id = 2, Name = "Bob", Age = 30 },
                new Person { Id = 3, Name = "Charlie", Age = 35 }
            };

            AddCommand = new MyCommand(AddPerson);
            DeleteCommand = new MyCommand(DeletePerson);
            UpdateCommand = new MyCommand(UpdatePerson);
            SearchCommand = new MyCommand(SearchPerson);
        }


        /// <summary>
        /// 增
        /// </summary>
        /// <param name="parameter"></param>

        private void AddPerson()
        {
            var newPerson = new Person();
            var editViewModel = new EditPersonViewModel(newPerson);
            var editWindow = new EditPersonWindow(editViewModel);

            editViewModel.CloseAction = (result) =>
            {
                editWindow.DialogResult = result;
                editWindow.Close();
            };

            if (editWindow.ShowDialog() == true)
            {
                newPerson.Id = Persons.Count + 1;
                Persons.Add(newPerson);
            }
        }

        /// <summary>
        /// 删
        /// </summary>
        /// <param name="parameter"></param>
        /// <returns></returns>
        private bool CanDeletePerson()
        {
            return SelectedPerson != null;
        }


        /// <summary>
        /// 删除
        /// </summary>
        /// <param name="parameter"></param>
        private void DeletePerson()
        {
            if (SelectedPerson != null)
            {
                var result = MessageBox.Show($"确认要删除 {SelectedPerson.Name} 吗？", "删除确认", MessageBoxButton.YesNo);
                if (result == MessageBoxResult.Yes)
                {
                    Persons.Remove(SelectedPerson);
                }
            }
        }
 

        /// <summary>
        /// 更新
        /// </summary>
        /// <param name="parameter"></param>
        private void UpdatePerson()
        {
            if (SelectedPerson != null)
            {
                var editViewModel = new EditPersonViewModel(SelectedPerson);
                var editWindow = new EditPersonWindow(editViewModel);

                editViewModel.CloseAction = (result) =>
                {
                    editWindow.DialogResult = result;
                    editWindow.Close();
                };

                if (editWindow.ShowDialog() == true)
                {
                    // 因为传递的是引用，修改已在窗口中完成
                }
            }
        }



        查询
        private void SearchPerson()
        {
            string sss = SelectTxt;
            if (sss!="")
            {
                var searchResult = new ObservableCollection<Person>();
                
                foreach (var person in Persons)
                {
                    if (person.Id==Convert.ToInt16(sss))
                    {
                        searchResult.Add(person);
                    }
                }
                Persons = searchResult;
                OnPropertyChanged(nameof(Persons));
            }
        }

      
    }
}