【ASP.NET Core学习】Razor页面

 这里介绍了Razor基本用法

  1. 创建带PageModel的Razor 页面
  2. 使用数据库
  3. 展示数据
  4. 更新数据
  5. 筛选器

准备工作

  1. 初始化空的项目(终端输入:dotnet new web -n=Razor)
  2. Nuget添加Microsoft.EntityFrameworkCore.SqlServer 和 Microsoft.EntityFrameworkCore.Design             
  3. 添加必要服务

   ConfigureServices添加Razor支持

public void ConfigureServices(IServiceCollection services)  {      services.AddRazorPages();  }

  修改app.UseEndpoints为

app.UseEndpoints(endpoints =>  {      endpoints.MapRazorPages();  });

 

添加数据库

 1. 添加模型

[Table("Book")]  public class Book  {      [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]      public int Id { get; set; }        [Display(Name = "书名")]      [Required(ErrorMessage = "书名不能为空")]      [StringLength(50, ErrorMessage = "书名最大长度为50")]      public string Name { get; set; }        [Display(Name = "单价")]      [Column(TypeName = "decimal(18, 2)")]      [Range(0.01, 10000, ErrorMessage = "单价范围只能在(0.01 ~ 10000)"), DataType(DataType.Currency)]      public decimal UnitPrice { get; set; }        [Display(Name = "出版日期")]      [DataType(DataType.Date), DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}")]      public DateTime PublicationDate { get; set; }        [Display(Name = "创建时间")]      [DataType(DataType.DateTime), DisplayFormat(DataFormatString = "{0:yyyy-MM-dd HH:mm:ss}")]      public DateTime CreateTime { get; set; }        [Display(Name = "最后更新时间")]      [DataType(DataType.DateTime), DisplayFormat(DataFormatString = "{0:yyyy-MM-dd HH:mm:ss}")]      public DateTime? LastUpdateTime { get; set; }  }

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 2. 添加DbContext

public class RazorDbContext : DbContext  {      public RazorDbContext(DbContextOptions<RazorDbContext> options)          : base(options)      {        }        public DbSet<Razor.Models.Book> Book { get; set; }  }

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3. 安装dotnet-ef(全局安装),终端输入

dotnet tool install --global dotnet-ef

4. 添加迁移
dotnet ef migrations add InitialDb

 5. 更新到数据库

dotnet ef database update InitialDb

 6. 添加种子数据

public static class SeedData  {      public static void Initialize(IServiceProvider serviceProvider)      {          var options = serviceProvider.GetRequiredService<DbContextOptions<RazorDbContext>>();          using (var context = new RazorDbContext(options))          {              if (context.Book.Any())              {                  return;              }                context.Book.AddRange(                  new Models.Book                  {                      Name = "算法之美",                      UnitPrice = 26.99m,                      PublicationDate = DateTime.Parse("2016-08-20"),                      CreateTime = DateTime.Now                  },                  new Models.Book                  {                      Name = "大话设计模式",                      UnitPrice = 28.03m,                      PublicationDate = DateTime.Parse("2015-06-12"),                      CreateTime = DateTime.Now                  },                  new Models.Book                  {                      Name = "幸福的陷阱",                      UnitPrice = 30.59m,                      PublicationDate = DateTime.Parse("2018-09-13"),                      CreateTime = DateTime.Now                  },                  new Models.Book                  {                      Name = "墨菲定律",                      UnitPrice = 32.12m,                      PublicationDate = DateTime.Parse("2018-09-13"),                      CreateTime = DateTime.Now                  }              );                context.SaveChanges();          }      }  }

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经过上面的步骤就可以在程序中使用数据库

 

Razor页面

一、路由
@page指令
  1. 必须是页面上的第一个 Razor 指令
  2. 默认情况,Url根据文件夹层次结构生成,也可以在@page 后面指定路由
  3. 可以对参数约束,例如:{id:int}

二、读取数据(以上面模型为例)

  1. 创建Index页面

dotnet new page -o=Pages -na="Razor.Pages" -n="Index"

  2. PageModel 的OnGet读取数据

public class IndexModel : PageModel  {      private readonly Data.RazorDbContext _dbContext;      public IndexModel(Data.RazorDbContext dbContext)      {          _dbContext = dbContext;      }        public List<Models.Book> Books { get; set; }        public IActionResult OnGet()      {          if (_dbContext == null)          {              return NotFound();          }            Books = _dbContext.Book                              .AsNoTracking()                              .ToList();          return Page();      }  }

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  3. 页面展示数据

@page  @model IndexModel  @{      ViewData["Title"] = "图书管理";  }  <table class="table table-bordered text-center">      <thead>          <tr>              <th>                  @Html.DisplayNameFor(model => model.Books[0].Name)              </th>              <th>                  @Html.DisplayNameFor(model => model.Books[0].UnitPrice)              </th>              <th>                  @Html.DisplayNameFor(model => model.Books[0].PublicationDate)              </th>              <th>                  @Html.DisplayNameFor(model => model.Books[0].CreateTime)              </th>              <th >                  @Html.DisplayNameFor(model => model.Books[0].LastUpdateTime)              </th>              <th></th>          </tr>      </thead>      <tbody>          @foreach (var item in Model.Books)          {              <tr>                  <td>                      @Html.DisplayFor(modelItem => item.Name)                  </td>                  <td>                      @Html.DisplayFor(modelItem => item.UnitPrice)                  </td>                  <td>                      @Html.DisplayFor(modelItem => item.PublicationDate)                  </td>                  <td>                      @Html.DisplayFor(modelItem => item.CreateTime)                  </td>                  <td>                      @Html.DisplayFor(modelItem => item.LastUpdateTime)                  </td>                  <td>                      <a asp-page="./Edit" asp-route-id="@item.Id">编辑</a> |                      <a asp-page="./Delete" asp-route-id="@item.Id">删除</a>                  </td>              </tr>          }      </tbody>  </table>

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三、更新数据

  1. 创建Edit页面

dotnet new page -o=Pages -na="Razor.Pages" -n="Edit"

  2. PageModel拉去数据

public IActionResult OnGet(int? id)  {      if (id == null)      {          return NotFound();      }        Book = _dbContext.Book                       .AsNoTracking()                       .FirstOrDefault(m => m.Id == id);        if(Book == null)      {          return NotFound();      }        return Page();  }

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  3. 编辑Edit页面

@page "{id:int}"  @model Razor.Pages.EditModel  @{      ViewData["Title"] = "编辑书本";  }  <div class="row">      <div class="col-md-4">          <form method="post">              <div asp-validation-summary="ModelOnly" class="text-danger"></div>              <input type="hidden" asp-for="Book.Id" />              <div class="form-group">                  <label asp-for="Book.Name" class="control-label"></label>                  <input asp-for="Book.Name" class="form-control" />                  <span asp-validation-for="Book.Name" class="text-danger"></span>              </div>              <div class="form-group">                  <label asp-for="Book.UnitPrice" class="control-label"></label>                  <input asp-for="Book.UnitPrice" class="form-control" />                  <span asp-validation-for="Book.UnitPrice" class="text-danger"></span>              </div>              <div class="form-group">                  <label asp-for="Book.PublicationDate" class="control-label"></label>                  <input asp-for="Book.PublicationDate" class="form-control" />                  <span asp-validation-for="Book.PublicationDate" class="text-danger"></span>              </div>              <div class="form-group">                  <input type="submit" value="保存" class="btn btn-primary" />              </div>          </form>      </div>  </div>

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  4. OnPost处理请求

public IActionResult OnPost()  {      if (!ModelState.IsValid)      {          return Page();      }        var model = _dbContext.Book.FirstOrDefault(m => m.Id == Book.Id);        if (model == null)      {          return NotFound();      }        model.Name = Book.Name;      model.PublicationDate = Book.PublicationDate;      model.UnitPrice = Book.UnitPrice;        _dbContext.SaveChanges();        return RedirectToPage("Index");  }

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用asp-for生成的输入框,会加上客户端验证,查看原代码可以发现

<input class="form-control" type="text" data-val="true" data-val-length="&#x4E66;&#x540D;&#x6700;&#x5927;&#x957F;&#x5EA6;&#x4E3A;50" data-val-length-max="50" data-val-required="&#x4E66;&#x540D;&#x4E0D;&#x80FD;&#x4E3A;&#x7A7A;" id="Book_Name" maxlength="50" name="Book.Name" value="&#x5927;&#x8BDD;&#x8BBE;&#x8BA1;&#x6A21;&#x5F0F;" />

它是根据模型定义的验证,生成属性,然后用jquery-validation验证,这样我们没有写一行前端代码就能达到客户端验证效果,微软真的把DRY做到极致。当然后端的验证也是不能漏的

 

筛选器

Razor 页面筛选器提供的以下方法可在全局或页面级应用:

同步方法:

  • OnPageHandlerSelected:在选择处理程序方法后但在模型绑定发生前调用。
  • OnPageHandlerExecuting:在执行处理器方法前,模型绑定完成后调用。
  • OnPageHandlerExecuted:在执行处理器方法后,生成操作结果前调用。

异步方法:

  • OnPageHandlerSelectionAsync:在选择处理程序方法后,但在模型绑定发生前,进行异步调用。
  • OnPageHandlerExecutionAsync:在调用处理程序方法前,但在模型绑定结束后,进行异步调用。
一、全局筛选器
  1. 定义GlobalPageFilter,实现IPageFilter接口

public class GlobalPageFilter : IPageFilter  {      private readonly ILogger _logger;        public GlobalPageFilter(ILoggerFactory loggerFactory)      {          _logger = loggerFactory.CreateLogger<GlobalPageFilter>();      }        public void OnPageHandlerExecuted(PageHandlerExecutedContext context)      {          _logger.LogDebug("Global Filter OnPageHandlerSelected called.");      }        public void OnPageHandlerExecuting(PageHandlerExecutingContext context)      {          _logger.LogDebug("Global Filter OnPageHandlerExecuting called.");      }        public void OnPageHandlerSelected(PageHandlerSelectedContext context)      {          _logger.LogDebug("Global Filter OnPageHandlerSelected called.");      }  }

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   2. ConfigureServices添加筛选器

services.AddMvc(options =>  {      options.Filters.Add<Filters.GlobalPageFilter>();  });

二、特定PageModel筛选器
  在PageModel里面重载

public override void OnPageHandlerSelected(Microsoft.AspNetCore.Mvc.Filters.PageHandlerSelectedContext context)  {      _logger.LogDebug("OnPageHandlerSelected");  }  //在执行处理器方法前,模型绑定完成后调用  public override void OnPageHandlerExecuting(Microsoft.AspNetCore.Mvc.Filters.PageHandlerExecutingContext context)  {      _logger.LogDebug("OnPageHandlerExecuting");  }  //在执行处理器方法后,生成操作结果前调用  public override void OnPageHandlerExecuted(Microsoft.AspNetCore.Mvc.Filters.PageHandlerExecutedContext context)  {      _logger.LogDebug("OnPageHandlerExecuted");  }

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示例代码:https://github.com/WilsonPan/AspNetCoreExamples/tree/master/Razor