使用EntityFramework Core和Enums作为字符串的ASP.NET Core Razor页面——第四部分

其他 2018-12-30 20:46:18 阅读次数: 0
版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/mzl87/article/details/85339183

目录

介绍

背景

使用代码

添加项目和项目技能处理

介绍

这是一篇由多部分组成的文章的第四部分，演示了通过EntityFramework Core 2.1（EF）将C＃enum值映射到数据库表中的string值。它解决了enum与应用程序实体的一对多和多对多关系中的值映射问题。它在ASP.NET Core Razor Page应用程序的上下文中执行此操作。

EF是对象关系映射器（ORM）。在诸如此示例的应用程序中，有两个“世界”。一个是在C＃中作为对象模型存在的对象世界。另一个是存在于关系数据库中的关系世界，如Microsoft SQL Server。这两个世界并不一致。ORM的功能，如EntityFramework，就是这两个世界之间的桥梁，并促进它们之间的数据传输。

第一部分。  设置实体框架数据上下文和初始客户Razor页面。（https://blog.csdn.net/mzl87/article/details/85269084）

第二部分。  为客户提供完整的CRUD功能。（https://blog.csdn.net/mzl87/article/details/85312335）

第三部分。创建Project和ProjectState实体，并在ProjectState和Projects之间实现一对多关系（https://blog.csdn.net/mzl87/article/details/85312583）

在第四部分：添加Skill 实体（Skill 枚举，SkillTitle 和ProjectSkill）并实现Projects 和Skills之间的多对多关系，如下所示：

  • 添加实体Skill，SkillTitle和ProjectSkill并配置到QuantumDbContext中。
  • 添加迁移，添加项目技能实体和更新数据库。
  • 搭建Skill相关的Razor页面，CustomerProjectSkills.cshtml，CustomerProjectSkillAssign.cshtml和CustomerProjectSkillDelete.cshtml。运行测试以确认功能。

背景

本系列中实施的示例应用程序适用于虚拟工程技术公司，量子工程技术公司。这家公司主要服务于石油，天然气和化学工业。到目前为止，我们已经讨论了对象模型的基础，并创建了许多ASP.NET Razor页面来处理客户，项目和项目状态。在最后一部分中，我们将讨论执行工作所需技能的列表。这项工作围绕Skill枚举和Skill与Projects之间的多对多关系构建。可能有许多项目需要某种技能。执行Project还需要很多Skill。因此，项目和技能实体之间存在多对多关系。

在关系数据库中，通过为两个实体创建连接表来实现多对多关系，如下所示。

通过连接表实现多对多关系

https://img-blog.csdnimg.cn/20181229152909526

表A和表B之间存在多对多关系。在关系数据库中，创建连接表JOIN-TABLE AB，与两个表具有一对多关系。

在先前版本的实体框架（EF）中，可以按约定配置连接表，而无需在对象模型中使用实体或类。但是，截至目前为止，Entity Framework Core尚未提供此功能。（参见  https://www.learnentityframeworkcore.com/configuration/many-to-many-relationship-configuration。）因此，我们需要在对象模型中创建和配置一个类来实现这一目的。以下讨论显示了如何使用相关的Razor页面来管理UI中的内容。

使用代码

工作对象模型显示在第一部分中，并在此处针对 Skills重复。

Skills的工作对象模型

https://img-blog.csdnimg.cn/20181229152909570

Skill.cs

namespace QuantumWeb.Model
{
    /// <summary>
    /// Skill Enumeration
    /// </summary>
    public enum Skill
    {
        Programmer, // Programmer
        ME,         // Mechanical Engineer
        ChE,        // Chemical Engineer
        CtrlE,      // Control Engineer
        SWE,        // Software Engineer
        SWArch,     // Software Architect
        WebDes,     // Web Designer
        DataSci,    // Data Scientist
        ProjMgr,    // Project Manager
        BusAnal,    // Business Analyst
        QA          // Quality Assurance Tester
    } // end public enum Skill

} // end namespace QuantumWeb.Model

我们提供了一个SkillTitle类，因此我们可以在UI中为枚举值提供相关的标题。

SkillTitle.cs

using System.Collections.Generic;

namespace QuantumWeb.Model
{
    /// <summary>
    /// SkillTitle Class
    /// </summary>
    public class SkillTitle
    {
        /// <summary>
        /// Skill Code
        /// </summary>
        public Skill SkillCode { get; set; }
        /// <summary>
        /// Skill Title
        /// </summary>
        public string Title { get; set; }

        #region Navigation Properties

        /// <summary>
        /// List of ProjectSkill Instances
        /// </summary>
        public List<ProjectSkill> ProjectSkills { get; set; }

        #endregion // Navigation Properties

    } // end public class SkillTitle

} // end namespace QuantumWeb.Model

此类引用类ProjectSkill，它将在数据库中配置连接的表。

ProjectSkill.cs

namespace QuantumWeb.Model
{
    /// <summary>
    /// ProjectSkill Class, a join entity
    /// </summary>
    /// <remarks>
    /// Note: The database table will have a non-unique index on ProjectId and SkillCode
    /// </remarks>
    public class ProjectSkill
    {

        /// <summary>
        /// ProjectSkill Identifier, primary key
        /// </summary>
        public int ProjectSkillId { get; set; }

        #region Navigation Properties

        /// <summary>
        /// Project Identifier
        /// </summary>
        public int ProjectId { get; set; }
        /// <summary>
        /// Project Reference
        /// </summary>
        public Project Project { get; set; }
        /// <summary>
        /// Skill Code
        /// </summary>
        public Skill SkillCode { get; set; }
        /// <summary>
        /// SkillTitle Reference
        /// </summary>
        public SkillTitle SkillTitle { get; set; }

        #endregion // Navigation Properties

    } // end public class ProjectSkill

} // end namespace QuantumWeb.Model

注意导航属性。它是对单个Project实例和单个SkillTitle实例的引用。ProjectId和SkillCode属性将映射到数据库中ProjectSkills表中的外键。另请注意，SkillTitle类具有集合属性ProjectSkills（List <ProjectSkill>），表明它可以与零个或多个ProjectSkill实例相关。我们现在必须修改Project类。

修改Project.cs

using System.Collections.Generic;

namespace QuantumWeb.Model
{
    /// <summary>
    /// Project Class
    /// </summary>
    public class Project
    {
        /// <summary>
        /// Project Identifier, primary key
        /// </summary>
        public int ProjectId { get; set; }
        /// <summary>
        /// Project Name
        /// </summary>
        public string ProjectName { get; set; }

        #region Navigation Properties

        /// <summary>
        /// Customer Identifier
        /// </summary>
        public int CustomerId { get; set; }

        /// <summary>
        /// Customer
        /// </summary>
        /// <remarks>
        /// Every Project has a Customer
        /// </remarks>
        public Customer Customer { get; set; }

        /// <summary>
        /// Project Status Code
        /// </summary>
        public ProjectState ProjectStateCode { get; set; }

        /// <summary>
        /// ProjectStateDescription Reference
        /// </summary>
        public ProjectStateDescription ProjectStateDescription { get; set; }

        /// <summary>
        /// List of ProjectSkill Instances
        /// </summary>
        public List<ProjectSkill> ProjectSkills { get; set; }

        #endregion // Navigation Properties

    } // end public class Project

} // end namespace QuantumApp.Model

这里我们添加了一个导航属性ProjectSkills  （List <ProjectSkill>），它允许Project与多个ProjectSkill实例相关联。

现在我们必须在QuantumDbContext类中配置这些类以创建数据库映射。  首先，我们创建SkillTitleConfiguration类。

SkillTitleConfiguration.cs

using System;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using QuantumWeb.Model;

namespace QuantumWeb.Data
{
    public class SkillTitleConfiguration : IEntityTypeConfiguration<SkillTitle>
    {
        public void Configure(EntityTypeBuilder<SkillTitle> builder)
        {
            builder.ToTable("SkillTitles");
            builder.HasKey(st => st.SkillCode);
            builder.Property(st => st.SkillCode)
            .HasColumnType("nvarchar(20)")
            .HasConversion(
                st => st.ToString(),
                st => (Skill)Enum.Parse(typeof(Skill), st));
            builder.Property(st => st.Title)
            .IsRequired()
            .HasColumnType("nvarchar(50)")
            .HasMaxLength(50);
        } // end public void Configure(EntityTypeBuilder<SkillTitle> builder)

    } // end public class SkillTitleConfiguration : IEntityTypeConfiguration<SkillTitle>

} // end namespace QuantumWeb.Data

这会将SkillTitle类映射到SkillTitles数据库表。它还可以在SkillTitles表中配置Skill枚举值和SkillCode字符串列值之间的转换。这类似于将ProjectState枚举值映射到第III部分中讨论的ProjectStateCode值。

我们现在可以配置ProjectSkill类到连接表ProjectSkills的映射。

ProjectSkillConfiguration.cs

using System;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using QuantumWeb.Model;

namespace QuantumWeb.Data
{
    public class ProjectSkillConfiguration : IEntityTypeConfiguration<ProjectSkill>
    {
        public void Configure(EntityTypeBuilder<ProjectSkill> builder)
        {
            builder.ToTable("ProjectSkills");
            builder.HasKey(ps => ps.ProjectSkillId);
            builder.Property(ps => ps.ProjectSkillId)
            .HasColumnType("int");
            builder.Property(ps => ps.ProjectId)
            .HasColumnType("int");
            builder.Property(ps => ps.SkillCode)
            .HasColumnType("nvarchar(20)")
            .HasConversion(
                ps => ps.ToString(),
                ps => (Skill)Enum.Parse(typeof(Skill), ps));
            builder.HasIndex(ps => new { ps.ProjectId, ps.SkillCode })
            .IsUnique(false);
            builder.HasOne<Project>(ps => ps.Project)
                .WithMany(p => p.ProjectSkills)
                .HasForeignKey(ps => ps.ProjectId);
            builder.HasOne<SkillTitle>(ps => ps.SkillTitle)
                .WithMany(p => p.ProjectSkills)
                .HasForeignKey(ps => ps.SkillCode);
        } // end public void Configure(EntityTypeBuilder<ProjectSkill> builder)

    } // end public class ProjectSkillConfiguration : IEntityTypeConfiguration<ProjectSkill>

} // end namespace QuantumWeb.Data

我们现在修改QuantumDbContext类以反映这些更改。

修改QuantumDbContext.cs

using Microsoft.EntityFrameworkCore;
using QuantumWeb.Model;

namespace QuantumWeb.Data
{
    public class QuantumDbContext : DbContext
    {
        public QuantumDbContext (DbContextOptions<QuantumDbContext> options)
            : base(options)
        {
        } // end public QuantumDbContext (DbContextOptions<QuantumDbContext> options)

        #region DbSets

        /// <summary>
        /// Customer DbSet
        /// </summary>
        public DbSet<Customer> Customers { get; set; }

        /// <summary>
        /// Project DbSet
        /// </summary>
        public DbSet<Project> Projects { get; set; }

        /// <summary>
        /// ProjectStateDescription DbSet
        /// </summary>
        public DbSet<ProjectStateDescription> ProjectStateDescriptions { get; set; }

        /// <summary>
        /// SkillTitle DbSet
        /// </summary>
        public DbSet<SkillTitle> SkillTitles { get; set; }

        /// <summary>
        /// ProjectSkill DbSet
        /// </summary>
        public DbSet<ProjectSkill> ProjectSkills { get; set; }

        #endregion // DbSets

        /// <summary>
        /// Data Model Creation Method
        /// </summary>
        /// <param name="modelBuilder">ModelBuilder instance</param>
        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.ApplyConfiguration(new CustomerConfiguration());
            modelBuilder.ApplyConfiguration(new ProjectConfiguration());
            modelBuilder.ApplyConfiguration(new ProjectStateDescriptionConfiguration());
            modelBuilder.ApplyConfiguration(new SkillTitleConfiguration());
            modelBuilder.ApplyConfiguration(new ProjectSkillConfiguration());
        } // end  protected override void OnModelCreating(ModelBuilder modelBuilder)

    } // end public class QuantumDbContext : DbContext

} // end namespace QuantumWeb.Data

这里我们定义DbSets，SkillTitles和ProjectSkills，并添加SkillTitleConfiguration和ProjectSkillConfiguration类以便在OnModelCreating方法中进行处理。现在，我们在Package Manager控制台中创建迁移并更新数据库。

Add-Migration Add-Project-Skill-Entities

生成20181025222456_Add-Project-Skill-Entities.cs

using Microsoft.EntityFrameworkCore.Metadata;
using Microsoft.EntityFrameworkCore.Migrations;

namespace QuantumWeb.Migrations
{
    public partial class AddProjectSkillEntities : Migration
    {
        protected override void Up(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.CreateTable(
                name: "SkillTitles",
                columns: table => new
                {
                    SkillCode = table.Column<string>(type: "nvarchar(20)", nullable: false),
                    Title = table.Column<string>(type: "nvarchar(50)", maxLength: 50, nullable: false)
                },
                constraints: table =>
                {
                    table.PrimaryKey("PK_SkillTitles", x => x.SkillCode);
                });

            migrationBuilder.CreateTable(
                name: "ProjectSkills",
                columns: table => new
                {
                    ProjectSkillId = table.Column<int>(type: "int", nullable: false)
                        .Annotation("SqlServer:ValueGenerationStrategy",
                            SqlServerValueGenerationStrategy.IdentityColumn),
                    ProjectId = table.Column<int>(type: "int", nullable: false),
                    SkillCode = table.Column<string>(type: "nvarchar(20)", nullable: false)
                },
                constraints: table =>
                {
                    table.PrimaryKey("PK_ProjectSkills", x => x.ProjectSkillId);
                    table.ForeignKey(
                        name: "FK_ProjectSkills_Projects_ProjectId",
                        column: x => x.ProjectId,
                        principalTable: "Projects",
                        principalColumn: "ProjectId",
                        onDelete: ReferentialAction.Cascade);
                    table.ForeignKey(
                        name: "FK_ProjectSkills_SkillTitles_SkillCode",
                        column: x => x.SkillCode,
                        principalTable: "SkillTitles",
                        principalColumn: "SkillCode",
                        onDelete: ReferentialAction.Cascade);
                });

            migrationBuilder.CreateIndex(
                name: "IX_ProjectSkills_SkillCode",
                table: "ProjectSkills",
                column: "SkillCode");

            migrationBuilder.CreateIndex(
                name: "IX_ProjectSkills_ProjectId_SkillCode",
                table: "ProjectSkills",
                columns: new[] { "ProjectId", "SkillCode" });
        }

        protected override void Down(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.DropTable(
                name: "ProjectSkills");

            migrationBuilder.DropTable(
                name: "SkillTitles");
        }
    }
}

有一些关键点需要考虑。

  1. SkillTitles表有一个主键SkillCode，它映射到Skill枚举中的值。
  2. ProjectSkills表有一个整数主键ProjectSkillId和两个外键ProjecId，用于链接到Project记录，SkillCode用于链接到SkillTitle记录。一些作者建议设置一个多值主键，ProjectId和SkillCode。这将为需要多种相同类型技能的项目设置一些问题。但是，我们设置了一个非唯一索引IX_ProjectSkills_ProjectId_SkillCode。

我们稍后会看到其中的一些功能。现在将迁移到数据库。

Update-Database

从SQL Server Management Studio（SSMS）生成的下图显示了相关的数据库表。

客户——项目——技能数据库图

https://img-blog.csdnimg.cn/20181229152909608

 

现在我们在UI中包含这些实体。首先，我们在CustomerProjects Index页面中创建ProjectSkills的链接。

修改后的CustomerProject.cshtml

@page "{id:int?}"
@model QuantumWeb.Pages.Customers.CustomerProjectsModel
@{
    ViewData["Title"] = "Customer Projects";
}

<h2>Customer Projects</h2>

<div>
    <h4>Customer</h4>
    <hr />
    <dl class="dl-horizontal">
        <dt>
            @Html.DisplayNameFor(model => model.Customer.CustomerId)
        </dt>
        <dd>
            @Html.DisplayFor(model => model.Customer.CustomerId)
        </dd>
        <dt>
            @Html.DisplayNameFor(model => model.Customer.CustomerName)
        </dt>
        <dd>
            @Html.DisplayFor(model => model.Customer.CustomerName)
        </dd>
        <dt>
            @Html.DisplayNameFor(model => model.Customer.Projects)
        </dt>
        <dd>
            <table class="table">
                <tr>
                    <th>Project ID</th>
                    <th>Project Name</th>
                    <th>Project State</th>
                    <th></th>
                </tr>
                @foreach (var item in Model.Customer.Projects)
                {
                <tr>
                    <td>
                        @Html.DisplayFor(modelItem => item.ProjectId)
                    </td>
                    <td>
                        @Html.DisplayFor(modelItem => item.ProjectName)
                    </td>
                    <td>
                        @Html.DisplayFor(modelItem => item.ProjectStateCode)
                    </td>
                    <td>
                        <a asp-page="./CustomerProjectSkills" asp-route-id="@item.ProjectId">
                            ProjectSkills
                        </a> |
                        <a asp-page="./CustomerProjectEdit" asp-route-id="@item.ProjectId">Edit</a> |
                        <a asp-page="./CustomerProjectDelete" asp-route-id="@item.ProjectId">Delete</a>
                    </td>
                </tr>
                }
            </table>
        </dd>
    </dl>
</div>

<div>
    <a asp-page="CustomerProjectCreate" asp-route-id="@Model.Customer.CustomerId">
        Create New Project
    </a> |
    <a asp-page="./Index">Back to List</a>
</div>

CustomerProjectSkills的链接要求我们构建一个新的Razor页面。

构建Customers/CustomerProjectSkills Razor页面

https://img-blog.csdnimg.cn/20181229152909657

初始化~Pages\Customers\CustomerProjectSkills.cshtml

@page "{id:int?}"
@model QuantumWeb.Pages.Customers.CustomerProjectSkillsModel
@{
    ViewData["Title"] = "Customer Project Skills";
}

<h2>Customer Project Skills</h2>

<p>
    <a asp-page="./CustomerProjects" asp-route-id="@Model.Customer.CustomerId">Back to List</a> |
    <a asp-page="CustomerProjectSkillAssign" asp-route-id="@Model.Project.ProjectId">Assign Skill</a>
</p>
<div>
    <h4>Customer-Project</h4>
    <hr />
    <dl class="dl-horizontal">
        <dt>
            @Html.DisplayNameFor(model => model.Customer.CustomerId)
        </dt>
        <dd>
            @Html.DisplayFor(model => model.Customer.CustomerId)
        </dd>
        <dt>
            @Html.DisplayNameFor(model => model.Customer.CustomerName)
        </dt>
        <dd>
            @Html.DisplayFor(model => model.Customer.CustomerName)
        </dd>
        <dt>
            @Html.DisplayNameFor(model => model.Project.ProjectId)
        </dt>
        <dd>
            @Html.DisplayFor(model => model.Project.ProjectId)
        </dd>
        <dt>
            @Html.DisplayNameFor(model => model.Project.ProjectName)
        </dt>
        <dd>
            @Html.DisplayFor(model => model.Project.ProjectName)
        </dd>
        <dt>
            @Html.DisplayNameFor(model => model.Project.ProjectSkills)
        </dt>
        <dd>
            <table class="table">
                <tr>
                    <th>Project Skill Id</th>
                    <th>Skill Code</th>
                    <th>Skill Title</th>
                    <th></th>
                </tr>
                @foreach (var item in Model.Project.ProjectSkills)
                {
                    <tr>
                        <td>
                            @Html.DisplayFor(modelItem => item.ProjectSkillId)
                        </td>
                        <td>
                            @Html.DisplayFor(modelItem => item.SkillCode)
                        </td>
                        <td>
                            @Html.DisplayFor(modelItem => item.SkillTitle.Title)
                        </td>
                        <td>
                            <a asp-page="./CustomerProjectSkillDelete"
                              asp-route-id="@item.ProjectSkillId">
                                  Delete
                            </a>
                        </td>
                    </tr>
                }
            </table>
        </dd>
    </dl>
</div>

这会将页面配置为使用可为空的参数id，这将允许将目标Project的ProjectId传递给OnGet处理程序。有一个指向CustomerProjectSkillAssign页面的链接，该页面将创建一个ProjectSkill记录，有效地为项目分配技能。还有另一个指向CustomerProjectSkillDelete页面的链接，该页面将删除ProjectSkill记录。我们稍后会显示这两页的代码。

初始化~Pages\Customers\CustomerProjectSkills.cshtml.cs

using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.EntityFrameworkCore;
using QuantumWeb.Data;
using QuantumWeb.Model;

namespace QuantumWeb.Pages.Customers
{
    public class CustomerProjectSkillsModel : PageModel
    {

        private readonly QuantumDbContext _context;

        public CustomerProjectSkillsModel(QuantumDbContext context)
        {
            _context = context;
        } // end public CustomerProjectSkillsModel(QuantumDbContext context)

        public Project Project { get; set; }
        public Customer Customer { get; set; }

        public async Task<IActionResult> OnGet(int? id)
        {
            if (id == null)
            {
                return NotFound();
            } // endif (id == null)

            Project = await _context.Projects
                .Include(p => p.Customer)
                .Include(p => p.ProjectSkills)
                    .ThenInclude(ps => ps.SkillTitle)
                    .FirstOrDefaultAsync(p => p.ProjectId == id);

            if (Project == null)
            {
                return NotFound();
            } // endif (Project == null)

            Customer = Project.Customer;

            return Page();
        } // end public async Task<IActionResult> OnGet(int? id)

    } // end public class CustomerProjectSkillsModel : PageModel

} // end namespace QuantumWeb.Pages.Customers

请注意实体框架（EF）预加载的示例。

           

 Project = await _context.Projects
                .Include(p => p.Customer)
                .Include(p => p.ProjectSkills)
                    .ThenInclude(ps => ps.SkillTitle)
                    .FirstOrDefaultAsync(p => p.ProjectId == id);

在EF中，使用include()和include扩展方法在单个查询中检索与预加载相关的实体。在这里，我们检索项目的相关Customer和ProjectSkills实体，其ProjectId具有输入参数id的值。该查询更进一步使用ThenInclude()方法检索与检索到的ProjectSkills相关联的SkillTitles。

接下来的几个屏幕截图显示了导航到此页面的顺序。

QuantumWeb应用程序主页：https//localhost:44306/

https://www.codeproject.com/KB/dotnet/1264741/QuantumWeb-Home-1-1.jpg

QuantumWeb应用程序客户索引页：https//localhost: 44306/Customers

https://img-blog.csdnimg.cn/20181229152909710

客户项目页面包含Mirarex Oil & Gas（已添加ProjectSkills链接）的2个项目

https://img-blog.csdnimg.cn/20181229152909710

Mirarex Oil＆Gas，Zolar Pipeline的客户项目技能页面（无技能）

https://img-blog.csdnimg.cn/20181229152909791

我们现在展示CustomerProjectSkillAssign Razor页面的构建。

构建Customers/CustomerProjectSkillAssign Razor页面

https://img-blog.csdnimg.cn/20181229152909845

初始化~Pages\Customers\CustomerProjectSkillAssign.cshtml.cs

using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.EntityFrameworkCore;
using QuantumWeb.Data;
using QuantumWeb.Model;

namespace QuantumWeb.Pages.Customers
{
    public class CustomerProjectSkillAssignModel : PageModel
    {
        private readonly QuantumDbContext _context;

        public CustomerProjectSkillAssignModel(QuantumDbContext context)
        {
            _context = context;
        } // end public CustomerProjectSkillAssignModel(QuantumDbContext context)

        [BindProperty]
        public Project Project { get; set; }
        [BindProperty]
        public Customer Customer { get; set; }

        [BindProperty]
        public SkillTitle SkillTitle { get; set; }

        public async Task<IActionResult> OnGet(int? id)
        {
            if (id == null)
            {
                return NotFound();
            } // endif (id == null)

            Project = await _context.Projects
                .Include(p => p.Customer)
                .Include(p => p.ProjectSkills)
                    .ThenInclude(ps => ps.SkillTitle)
                    .FirstOrDefaultAsync(p => p.ProjectId == id);

            if (Project == null)
            {
                return NotFound();
            } // endif (Project == null)

            Customer = Project.Customer;

            ViewData["SkillCode"] = new SelectList(_context.SkillTitles, "SkillCode", "Title");

            return Page();
        }// end public async Task<IActionResult> OnGet(int? id)

        public async Task<IActionResult> OnPostAsync()
        {
            if (!ModelState.IsValid)
            {
                return Page();
            } // endif (!ModelState.IsValid)

            ProjectSkill projectSkill = new ProjectSkill()
            {
                ProjectId = Project.ProjectId,
                SkillCode = SkillTitle.SkillCode
            };

            _context.ProjectSkills.Add(projectSkill);
            await _context.SaveChangesAsync();

            return RedirectToPage("./CustomerProjectSkills", new { id = Project.ProjectId });
        } // end public async Task<IActionResult> OnPostAsync()

    } // end public class CustomerProjectSkillAssignModel : PageModel

} // end namespace QuantumWeb.Pages.Customers

在这里，我们再次使用ViewData来设置选择列表，如第III部分所述。

ViewData["SkillCode"] = new SelectList(_context.SkillTitles, "SkillCode", "Title");

这次它处理SkillTitles以选择与项目关联的技能。

初始化~Pages\Customers\CustomerProjectSkillAssign.cshtml

@page "{id:int?}"
@model QuantumWeb.Pages.Customers.CustomerProjectSkillAssignModel
@{
    ViewData["Title"] = "Customer Project Skill Assignment";
}

<h2>Customer Project Skill Assignment</h2>
<hr />
<dl class="dl-horizontal">
    <dt>
        @Html.DisplayNameFor(model => model.Project.ProjectId)
    </dt>
    <dd>
        @Html.DisplayFor(model => model.Project.ProjectId)
    </dd>
    <dt>
        @Html.DisplayNameFor(model => model.Project.ProjectName)
    </dt>
    <dd>
        @Html.DisplayFor(model => model.Project.ProjectName)
    </dd>
    <dt>
        @Html.DisplayNameFor(model => model.Customer.CustomerId)
    </dt>
    <dd>
        @Html.DisplayFor(model => model.Customer.CustomerId)
    </dd>
    <dt>
        @Html.DisplayNameFor(model => model.Customer.CustomerName)
    </dt>
    <dd>
        @Html.DisplayFor(model => model.Customer.CustomerName)
    </dd>
</dl>
<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="Project.ProjectId" />
            <div class="form-group">
                <label asp-for="SkillTitle.SkillCode" class="control-label"></label>
                <select asp-for="SkillTitle.SkillCode" class="form-control" asp-items="ViewBag.SkillCode"></select>
            </div>
            <div class="form-group">
                <a asp-page="./CustomerProjectSkills" asp-route-id="Project.ProjectId">Project Skills</a> |
                <input type="submit" value="Assign" class="btn btn-default" />
            </div>
        </form>
    </div>
</div>

Zolar Pipeline的客户项目技能分配页面（技能选择打开）

https://www.codeproject.com/KB/dotnet/1264741/CustProjSkillAssign-01.jpg

Zolar Pipeline的客户项目技能分配页面（分配一个程序员）

https://img-blog.csdnimg.cn/20181229152909888

Mirarex Oil＆Gas，Zolar Pipeline的客户项目技能页面（程序员分配）

https://img-blog.csdnimg.cn/20181229152909888

分配了几个技能之后，这个页面看起来像：

Mirarex Oil & Gas, Zolar Pipeline 的客户项目技能页面（几项技能）

https://img-blog.csdnimg.cn/20181229152910121

管理层决定分配的程序员太多，因此我们需要删除一个。我们现在将构建CustomerProjectSkillDelete页面。

构建Customers/CustomerProjectSkillDelete Razor Page

https://www.codeproject.com/KB/dotnet/1264741/CreateCustProjSkillDelete-01.jpg

初始化~Pages\Customers\CustomerProjectSkillDelete.cshtml.cs

using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.EntityFrameworkCore;
using QuantumWeb.Data;
using QuantumWeb.Model;

namespace QuantumWeb.Pages.Customers
{
    public class CustomerProjectSkillDeleteModel : PageModel
    {
        private readonly QuantumDbContext _context;

        public CustomerProjectSkillDeleteModel(QuantumDbContext context)
        {
            _context = context;
        } // end public CustomerProjectSkillDeleteModel(QuantumDbContext context)

        [BindProperty]
        public Customer Customer { get; set; }
        [BindProperty]
        public Project Project { get; set; }

        public async Task<IActionResult> OnGetAsync(int? id)
        {
            if (id == null)
            {
                return NotFound();
            } // endif (id == null)

            Project = await _context.Projects
                .Include(p => p.Customer)
                    .FirstOrDefaultAsync(p => p.ProjectId == id);

            if (Project == null)
            {
                return NotFound();
            } // endif (Project == null)

            Customer = Project.Customer;

            return Page();
        } // end public async Task<IActionResult> OnGet(int? id)

        public async Task<IActionResult> OnPostAsync(int? id)
        {
            if (id == null)
            {
                return NotFound();
            } // endif (id == null)

            Project = await _context.Projects
                .Include(p => p.Customer)
                .FirstOrDefaultAsync(p => p.ProjectId == id);

            if (Project != null)
            {
                _context.Projects.Remove(Project);
                await _context.SaveChangesAsync();
            } // endif (Project != null)

            return RedirectToPage("./CustomerProjectSkills", new { id = Project.Customer.CustomerId });
        } // end public async Task<IActionResult> OnPostAsync(int? id)

    } // end public class CustomerProjectSkillDeleteModel : PageModel

} // end namespace QuantumWeb.Pages.Customers

初始化~Pages\Customers\CustomerProjectSkillDelete.cshtml

@page "{id:int?}"
@model QuantumWeb.Pages.Customers.CustomerProjectDeleteModel
@{
    ViewData["Title"] = "Delete Customer Project";
}

<h2>Delete Customer Project</h2>

<h3>Are you sure you want to delete this?</h3>
<div>
    <dl class="dl-horizontal">
        <dt>
            @Html.DisplayNameFor(model => model.Customer.CustomerName)
        </dt>
        <dd>
            @Html.DisplayFor(model => model.Customer.CustomerName)
        </dd>
        <dt>
            @Html.DisplayNameFor(model => model.Project.ProjectId)
        </dt>
        <dd>
            @Html.DisplayFor(model => model.Project.ProjectId)
        </dd>
        <dt>
            @Html.DisplayNameFor(model => model.Project.ProjectName)
        </dt>
        <dd>
            @Html.DisplayFor(model => model.Project.ProjectName)
        </dd>
        <dt>
            @Html.DisplayNameFor(model => model.Project.ProjectStateCode)
        </dt>
        <dd>
            @Html.DisplayFor(model => model.Project.ProjectStateCode)
        </dd>
    </dl>

    <form method="post">
        <input type="hidden" asp-for="Project.ProjectId" />
        <a asp-page="CustomerProjects" asp-route-id="@Model.Customer.CustomerId">Back to Customer Projects</a> |
        <input type="submit" value="Delete" class="btn btn-default" />
    </form>
</div>

Mirarex Oil & Gas, Zolar Pipeline的客户项目技术删除页面 

https://img-blog.csdnimg.cn/20181229152910172

Mirarex Oil＆Gas，Zolar Pipeline的客户项目技能页面（已删除记录）

https://img-blog.csdnimg.cn/20181229152910238

 

原文地址：https://www.codeproject.com/Articles/1264741/ASP-NET-Core-Razor-Pages-Using-EntityFramework-C-3

猜你喜欢

转载自blog.csdn.net/mzl87/article/details/85339183
今日推荐
Arc Browser for Windows 1.0 正式 GA
90后程序员开发视频搬运软件、不到一年获利超 700 万，结局很刑！
《美国对全球网络空间安全与发展的威胁和破坏》报告发布
火速冲上 GitHub 热榜 —— 开源编程语言、框架哪有这么可爱？
北京人形机器人创新中心发布全球首个纯电驱拟人奔跑的全尺寸人形机器人“天工”
周排行
rbac——界面、权限
Apache CXF + SpringMVC 整合发布WebService
so插件化
Vue.js实战系列---图标字体制作（svg格式）
PAT乙级 1007 素数对猜想(孪生素数对) (20分) ---（C语言 + 详细注释）
被IRM保护的文档，打开失败
Calendar和Date计算日期差的小问题
win10子系统ubuntu18.4安装docker
利用Wrap Shell Script定位Android Native内存泄漏
MySQL: Transaction (Part I - Basic Concept)
每日归档
更多
2024-05-03(19)
2024-05-02(0)
2024-05-01(4)
2024-04-30(1)
2024-04-29(40)
2024-04-28(0)
2024-04-27(56)
2024-04-26(39)
2024-04-25(22)
2024-04-24(36)

代码天地 © 2018 codetd.com

境外服务器   最新电视剧2022