/*没有在xaml设置上下文window.context是因为 命名空间一直对应不上  所以在xaml.cs
里面绑定*/
<Window x:Class="DataGrid.views.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:DataGrid"xmlns:AutoGrid="clr-namespace:WpfAutoGrid"xmlns:viewmodels="clr-namespace:DataGrid.viewmodels"mc:Ignorable="d"Title="MainWindow" Height="450" Width="800"><Grid><AutoGrid:AutoGrid ColumnCount="2" RowCount="2"  Rows="5*,*" Columns="*,*" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"><DataGrid Grid.ColumnSpan="2" ItemsSource="{Binding Itemsview}"></DataGrid><TextBox HorizontalContentAlignment="Center" VerticalContentAlignment="Center" Text="{Binding Pagenum}" ></TextBox><Button HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Command="{Binding NextPageCommand}">Next</Button></AutoGrid:AutoGrid></Grid>
</Window>

using Bogus;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Controls;
using System.Windows.Data;
using Bogus;
using System.Collections.ObjectModel;namespace DataGrid.viewmodels
{public class student   //类变量要是属性getset{public int Id { get; set; }public string Name { get; set; }public double Score { get; set; }}public class StudentDataGenerator{public static ObservableCollection<student> GenerateStudents(int count){var fakeStudents = new Faker<student>().RuleFor(s => s.Id, f => f.IndexGlobal + 1)  // ID从1开始.RuleFor(s => s.Name, f => f.Name.FullName())    // 随机姓名.RuleFor(s => s.Score, f => f.Random.Double(0, 100)) // 0-100的随机分数.Generate(count);  // 生成指定数量的学生return new ObservableCollection<student>(fakeStudents);}}  /*bogus生成数据*/public partial class DataControl:ObservableObject /*这里一定要partial*/{private CollectionView _itemsview;private const int _pagesize = 10;private int _pagenum = 1;public CollectionView Itemsview { get { return _itemsview; } }public int Pagenum{get { return _pagenum; }set { SetProperty(ref _pagenum, value); Itemsview?.Refresh(); }}public int TotalPages => (int)Math.Ceiling(Students.Count / (double)_pagesize);[ObservableProperty]ObservableCollection<student> _students;[RelayCommand]public void NextPage(){if (_pagenum < TotalPages) // 如果还有下一页{Pagenum++;   //这里一定只能改属性  }}[RelayCommand]     //relaycommand生成的命令会在函数后面加上commandpublic void PrevPage(){if (_pagenum > 1) // 如果不是第1页{Pagenum--;}}//原理就是_itemsview匹配数据 过滤之后留下页码是1的内容 返回true的内容会被存入_itemsviewpublic DataControl(ObservableCollection<student> stus) //有参构造函数传数据{this._students = stus;    //这里要用observablecollection 不能用enumerable_itemsview = (CollectionView)CollectionViewSource.GetDefaultView(this._students);_itemsview.Filter = (item) =>{var index = Students.IndexOf((student)item); int itemPage = (index / _pagesize) + 1;return itemPage == Pagenum; // 只显示当前页的数据;};}}}

using System.Text;
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.Navigation;
using System.Windows.Shapes;
using DataGrid.viewmodels;namespace DataGrid.views
{/// <summary>/// Interaction logic for MainWindow.xaml/// </summary>public partial class MainWindow : Window{public MainWindow(){InitializeComponent();this.DataContext = new DataControl(StudentDataGenerator.GenerateStudents(36));}}
}//xaml不好绑定viewmodel  就只能到cs里面绑定了  this.datacontext = new ........
//坏处就是xaml不会有提示

sqlsugar操作

using SqlSugar;
using System;public static class IntDbHelper
{private static SqlSugarScope Connection => new SqlSugarScope(new ConnectionConfig(){ConnectionString = "Data Source=./data.db",DbType = DbType.Sqlite,IsAutoCloseConnection = true});// -------------------- 针对int值的操作 --------------------// 插入数据（返回新增的ID）public static int Insert(string tableName, Dictionary<string, object> values){return Connection.Insertable(values).AS(tableName).ExecuteReturnIdentity();}// 查询数据（返回单个int值）public static int GetInt(string tableName, string field, int id){return Connection.Queryable<dynamic>().AS(tableName).Where($"Id = {id}").Select(field).First();}// 更新数据（更新指定int字段）public static bool UpdateInt(string tableName, int id, string field, int newValue){return Connection.Updateable<dynamic>().AS(tableName).SetColumns($"{field} = {newValue}").Where($"Id = {id}").ExecuteCommand() > 0;}// 删除数据（根据int ID）public static bool Delete(string tableName, int id){return Connection.Deleteable<dynamic>().AS(tableName).Where($"Id = {id}").ExecuteCommand() > 0;}
}

int step = 0;
var result = from person in people
let currentId = step
select new
{
Id = (step += 2) - 2, // 0, 2, 4...
Person = person
};

不用直接操作id 可以linq给序号

linq里面只能OfType<student>() 不能强转

datagrid 返回的 selecteditems 是IList类型的

CollectionView 方式

优点：自动处理分页，删除后自动回填

缺点：需要调用 Refresh() 刷新视图

会自动回填

linq加反射则不会自动回填

Dictionary<int, string> dict = new Dictionary<int, string>();
dict[1] = "Apple"; // 键 1 不存在，自动添加键值对 {1: "Apple"}
dict[2] = "Banana"; // 键 2 不存在，自动添加键值对 {2: "Banana"}
dict[1] = "Avocado"; // 键 1 已存在，直接覆盖值，变成 {1: "Avocado"}