【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. 创建GlobalPageFilter类，实现IPageFilter接口

public class GlobalPageFilter : IPageFilter{    private readonly ILogger _logger;    public GlobalPageFilter(ILogger logger)    {        _logger = logger;    }    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. 创建过滤器工厂类，实现IFilterFactory接口

public class GlobalPagerFilterWithFactory : IFilterFactory{    public bool IsReusable => false;    public IFilterMetadata CreateInstance(IServiceProvider serviceProvider)    {        var logger = serviceProvider.GetService<ILogger<Filters.GlobalPageFilter>>();        return new Filters.GlobalPageFilter(logger);    }}

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　　3. ConfigureServices添加RazorPage选项

services.AddRazorPages()        .AddRazorPagesOptions(options =>        {            options.Conventions.ConfigureFilter(new Factories.GlobalPagerFilterWithFactory());        });

 

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