asp.net core mvc Razor +dapper 增删改查，分页（保姆教程）-编程知识

说明：本demo使用sqlserver数据库，dapper orm框架完成一张学生信息表的增删改查，前端部分使用的是Razor视图，
Linq分页 HtmlHelper。（代码随便写的，具体可以自己优化）
//实现效果如下（首页）
在这里插入图片描述
//新增页

//修改页

//删除

1.使用visual stuido 2022创建 asp.net core mvc项目（选择如下图）

2.安装dapper nuget包（选择第一个）

3.使用sqlserver创建数据库和数据表

USE [stu]
GO/****** Object:  Table [dbo].[StuInfo]    Script Date: 2023/9/28 18:17:23 ******/
SET ANSI_NULLS ON
GOSET QUOTED_IDENTIFIER ON
GOCREATE TABLE [dbo].[StuInfo]([Id] [int] NULL,[Name] [nchar](10) NULL,[Sex] [nchar](10) NULL,[Age] [int] NULL,[BirthDate] [date] NULL
) ON [PRIMARY]
GO

4.在项目appsetting中配置数据库连接字符串（填写自己的用户名和密码，和数据库信息）

{"Logging": {"LogLevel": {"Default": "Information","Microsoft.AspNetCore": "Warning"}},"AllowedHosts": "*","ConnectionStrings": {"connectionString": "Data Source=.;Initial Catalog=stu;User ID=sa;Password=pe123;TrustServerCertificate=true"}
}

5.创建数据学生信息实体类

namespace mvccore.dataModel
{public class StuInfo{public int Id { get; set; }public string? Name { get; set; }public string? Sex { get; set; }public int Age { get; set; }public DateTime BirthDate { get; set; }}
}

6.创建学生信息dto类

namespace mvccore.ViewModel
{public class stuViewModel{public int Id { get; set; }public string? Name { get; set; }public string? Sex { get; set; }public int Age { get; set; }}
}

7.创建stu的接口和实现类service(使用ioc注入面向接口编程)
创建接口和实现类后需要在program中注入服务
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using mvccore.dataModel;
using mvccore.ViewModel;namespace mvccore.service
{public interface Istuservice{//查询List<stuViewModel> stuls();void save<T>(T stu);void edit<T>(T t);//删除void delete(int Id);//根据Id查询stuViewModel GetById(int Id);}
}

using mvccore.ViewModel;
using Dapper;
using Microsoft.Data.SqlClient;
using System.Collections.Generic;
using System.Collections;
using mvccore.dataModel;namespace mvccore.service
{public class stuservice : Istuservice{private readonly IConfiguration _configuration;public string connstring { get; set; }public stuservice(IConfiguration configuration){_configuration = configuration;connstring = _configuration.GetConnectionString("connectionString");}//删除public void delete(int Id){using (var connection = new SqlConnection(connstring)){string sql = "delete from StuInfo where Id=@Id";connection.Execute(sql, new { Id });}}//显示所有列表public List<stuViewModel> stuls(){using (var connection = new SqlConnection(connstring)){string sql = "select * from StuInfo";var list = connection.Query<stuViewModel>(sql).ToList();return list;}}//新增public void save<T>(T stu1){var stu = stu1 as stuViewModel;using (var connection = new SqlConnection(connstring)){string sql = "insert into StuInfo(Id,Name,Sex,Age) values(@Id,@Name,@Sex,@Age);";DynamicParameters parameters = new DynamicParameters();parameters.Add("Id", 20);parameters.Add("Name", stu.Name);parameters.Add("Sex", stu.Sex);parameters.Add("Age", stu.Age);connection.Execute(sql, parameters);}}//编辑public void edit<T>(T t){var stu = t as stuViewModel;string sql = "update StuInfo set Name=@Name,Age=@Age WHERE Id=@Id";using (var connection = new SqlConnection(connstring)){connection.Execute(sql, new { Name = stu?.Name, Age = stu?.Age, Id = stu?.Id });}}//根据Id查询public stuViewModel GetById(int Id){string sql = "select * from StuInfo where Id=@Id";using (var connection = new SqlConnection(connstring)){var list = connection.Query<stuViewModel>(sql, new { Id = Id }).FirstOrDefault();return list;}}}
}

8.创建分页类

namespace WebApplication4
{public class PaginatedList<T> : List<T>{public int PageIndex { get; private set; }public int TotalPages { get; private set; }public PaginatedList(List<T> items, int count, int pageIndex, int pageSize){PageIndex = pageIndex;TotalPages = (int)Math.Ceiling(count / (double)pageSize);this.AddRange(items);}public bool HasPreviousPage => PageIndex > 1;public bool HasNextPage => PageIndex < TotalPages;public static PaginatedList<T> Create(IQueryable<T> source, int pageIndex, int pageSize){var count = source.Count();var items = source.Skip((pageIndex - 1) * pageSize).Take(pageSize).ToList();return new PaginatedList<T>(items, count, pageIndex, pageSize);}}
}

-------------------------------至此所有的业务代码就准备好了，接下来下控制器和视图里面的代码--------------------------------------------
9.创建stu的控制器
RedirectToAction(“StuInfoList”)：是指定跳转到当前控制器下的其他视图，这里我们跳转到首页

using Microsoft.AspNetCore.Mvc;
using mvccore.service;
using mvccore.ViewModel;
using WebApplication4;namespace mvccore.Controllers
{public class StuController : Controller{private readonly Istuservice _stuservice;public StuController(Istuservice stuservice){_stuservice = stuservice;}//学生列表视图public IActionResult StuInfoList(int? pageNumber = 1){var list = _stuservice.stuls().ToList();int pageSize = 3;return View(PaginatedList<stuViewModel>.Create(list.AsQueryable(), pageNumber ?? 1, pageSize));}//保存视图public IActionResult Save(){return View();}//保存方法public IActionResult Save2(stuViewModel stu){_stuservice.save<stuViewModel>(stu);return RedirectToAction("StuInfoList");}//删除方法（正式项目我们一般使用逻辑删除，不会真的把数据删掉）public IActionResult delete(int Id){_stuservice?.delete(Id);return RedirectToAction("StuInfoList");}//编辑回显public IActionResult edit(int Id){return View(_stuservice.GetById(Id));}//编辑方法public IActionResult edit2(stuViewModel stu){_stuservice?.edit(stu);return RedirectToAction("StuInfoList");}}
}

10.添加首页的视图（StuInfoList.cshtml）


@model PaginatedList<mvccore.ViewModel.stuViewModel>
@Html.ActionLink("新增","Save","Stu")
<table class="table"><tr><th>Name</th><th>Age</th><th>Sex</th><td>操作</td></tr>@foreach (var item in Model){<tr><td>@item.Name</td><td>@item.Age</td><td>@item.Sex</td><td> @Html.ActionLink("编辑","edit","Stu",new{item.Id})   @Html.ActionLink("删除","delete","Stu",new{@item.Id},new { onclick="return confirm('是否删除')" })</td></tr>}</table>
@{var prevDisabled = !Model.HasPreviousPage ? "disabled" : "";var nextDisabled = !Model.HasNextPage ? "disabled" : "";
}<a asp-action="StuInfoList"asp-route-pageNumber="@(Model.PageIndex - 1)"class="btn btn-default @prevDisabled">Previous
</a>
<a asp-action="StuInfoList"asp-route-pageNumber="@(Model.PageIndex + 1)"class="btn btn-default @nextDisabled">Next
</a>

11.添加新增视图（Save.cshtml）

<form action="/stu/Save2" method="post">
姓名：<input type="text" name="Name" />
年龄：<input type="text" name="Age"/>
性别:<input type="text" name="Sex"/>
<input type="submit" value="保存"/>
</form>

12.添加编辑视图（edit.cshtml)（可以和新增公用一个视图）

@using mvccore.ViewModel
@model stuViewModel;
<form action="/stu/edit2" method="post">姓名：<input type="text" name="Name" value="@Model.Name" />年龄：<input type="text" name="Age" value="@Model.Age" /><input type="hidden" name="Id" value="@Model.Id"/><input type="submit" value="保存" />
</form>

13.如果在解决方案中有多个项目的话，需要把当前项目设置为启动项目
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14.修改项目默认起始页，默认路由是 /Home/index(根据自己的需要更改)

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15.End 至此项目demo就完成了，下面是项目的结构图

代码随便写的，主要是快速入门。这边可以去微软官方文档上学习，有完整的代码实例(网址如下)
https://learn.microsoft.com/zh-cn/aspnet/core/tutorials/first-mvc-app/start-mvc?view=aspnetcore-7.0&tabs=visual-studio