使用Razor Pages将加载的对象发送到视图并从POST中获取更改

Question

在执行表查询、加载具有属性的对象并将其发送回视图后，我想更新一些属性并将其发布回Azure表。

我在我的Razor Page cs文件中有一个模型绑定，如下所示：

[BindProperty]
public TenantSettingsModel Settings { get; set; }

在我的OnGetAsync方法中，我加载Settings对象如下：

public async Task<IActionResult> OnGetAsync()
{
Settings = _azureTableConn.GetTenantSettings(passSomeValue);
return Page();
}

在这个阶段，我可以看到Settings加载了返回视图的属性。我只挑选了几个属性来显示在表单中，我想将这两个更改(如果有的话(以及其他未更改的属性发布回OnPostAsync方法，如下所示，并呈现一个视图：

public async Task<IActionResult> OnPostAsync()
{
var response = _azureTableconn.SetTenantSettings(Settings);
return Page();
}

当我检查Settings对象时，它有两个表单属性，但其他都为空。我可以简单地手动设置它们，但这似乎是一种浪费。

是否可以发送一个具有预定义属性的对象，然后在表单中更改其中两个属性，但在从视图返回时保留未更改的属性？

我唯一的其他想法是创建隐藏的表单元素来保存模型中的[in]绑定属性，但如果必须这样做，我最好在OnPostAsync方法中设置它。

Answer 1

我没有看到你的页面或代码，但我只是在CodeProject上发布了一些可能会有所帮助的帖子。您可能需要在.cs.html文件中使用表单元素。您的[BindProperty]属性将使TenantSettingsModel值可用于UI中的元素。您可以查看(ASP.NET Core Razor Pages Using EntityFramework Core with Enums as Strings-Part II(

我在这里使用实体框架核心。

在一个示例中，我编辑Razor页面上的Customer对象edit.cshtml([注意：我确实使用隐藏输入将Customer.CustomerId传递给PostAsync((方法](：

@page
@model QuantumWeb.Pages.Customers.EditModel
@{
ViewData["Title"] = "Edit";
}
<h2>Edit</h2>
<h4>Customer</h4>
<hr />
<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="Customer.CustomerId" />
<div class="form-group">
<label asp-for="Customer.CustomerName" class="control-label"></label>
<input asp-for="Customer.CustomerName" class="form-control" />
<span asp-validation-for="Customer.CustomerName"
class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Customer.CustomerContact"
class="control-label"></label>
<input asp-for="Customer.CustomerContact" class="form-control" />
<span asp-validation-for="Customer.CustomerContact"
class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Customer.CustomerPhone"
class="control-label"></label>
<input asp-for="Customer.CustomerPhone" class="form-control" />
<span asp-validation-for="Customer.CustomerPhone"
class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Customer.CustomerEmail"
class="control-label"></label>
<input asp-for="Customer.CustomerEmail" class="form-control" />
<span asp-validation-for="Customer.CustomerEmail"
class="text-danger"></span>
</div>
<div class="form-group">
<input type="submit" value="Save" class="btn btn-default" />
</div>
</form>
</div>
</div>
<div>
<a asp-page="./Index">Back to List</a>
</div>
@section Scripts {
@{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
}

"代码背后"，Edit.cshtml.cs:

using System.Linq;
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 EditModel : PageModel
{
private readonly QuantumDbContext _context;
public EditModel(QuantumDbContext context)
{
_context = context;
} // end public EditModel(QuantumDbContext context)
[BindProperty]
public Customer Customer { get; set; }
public async Task<IActionResult> OnGetAsync(int? id)
{
if (id == null)
{
return NotFound();
} // endif (id == null)
Customer =
await _context.Customers
.FirstOrDefaultAsync(m => m.CustomerId == id);
if (Customer == null)
{
return NotFound();
} // endif (Customer == null)
return Page();
} // end public async Task<IActionResult> OnGetAsync(int? id)
public async Task<IActionResult> OnPostAsync()
{
if (!ModelState.IsValid)
{
return Page();
} // endif (!ModelState.IsValid)
_context.Attach(Customer).State = EntityState.Modified;
try
{
await _context.SaveChangesAsync();
} // end try
catch (DbUpdateConcurrencyException)
{
if (!CustomerExists(Customer.CustomerId))
{
return NotFound();
}
else
{
throw;
} // endif (!CustomerExists(Customer.CustomerId))
} // end catch (DbUpdateConcurrencyException)
return RedirectToPage("./Index");
} // end public async Task<IActionResult> OnPostAsync()
private bool CustomerExists(int id)
{
return _context.Customers.Any(e => e.CustomerId == id);
} // end private bool CustomerExists(int id)
} // end public class EditModel : PageModel
} // end namespace QuantumWeb.Pages.Customers

我希望这能有所帮助。

在我的CodeProject帖子(第三部分和第四部分(中，我还有其他部分使用实体框架急切地加载GET中的相关数据。([使用以枚举为字符串的EntityFramework Core的ASP.NET Core Razor Pages-第三部分和使用以枚举作为字符串的EntityFrameworkCore的ASP.NET核心Razor Page-第四部分(

在第四部分中，我有一个页面，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>

请注意，我只有一个隐藏控件具有Project。项目ID客户项目技能分配.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

急切加载检索Project对象及其Customer对象及其ProjectSkills集合。每个ProjectSkill都有一个SkillTitle。此外，我将可用SkillTitle对象的集合加载到选择/下拉列表中。所选项通过窗体传递给OnPostAsync((。但是，只有一个隐藏控件用于指示目标项目。

Answer 2

我也有类似的挑战，不确定我的方法是否正确。我不是在DIV中显示(要编辑的(数据，而是在TABLE中显示。我可以理解隐藏属性是如何更新行的。在我的情况下，我在"编辑"页面上显示了多行，但无法仅更新有更新的行的数据库。

我的浏览页面是这样的

<form method="post">
<div asp-validation-summary="ModelOnly" class="text-danger"></div>        
<table class="table">
<thead>
<tr>
<th> @Html.DisplayNameFor(model => model.Fields[0].Name) </th>
<th> @Html.DisplayNameFor(model => model.Fields[0].Value) </th>
<th> @Html.DisplayNameFor(model => model.Fields[0].Confidence) </th>
<th></th>
</tr>
</thead>
<tbody>
@foreach (var item in Model.Fields)
{
<tr>
<td> <input type="hidden" asp-for=@item.ID /> </td>
<td> @Html.DisplayFor(modelItem => item.Name) </td>
<td contenteditable='true'> @Html.DisplayFor(modelItem => item.Value) </td>
<td> @Html.DisplayFor(modelItem => item.Confidence) </td>
</tr>
}
</tbody>
</table>
<div class="form-group">
<input type="submit" value="Save" class="btn btn-primary" />
</div>
</form>

背后的代码是这样的。Fields在OnPostAsync方法中显示0。

[BindProperty]
public IList<FieldInfo> Fields { get; set; }
public async Task<IActionResult> OnGetAsync(string id)
{
if (id == null)
{
return NotFound();
}
Fields = await _context.FieldInfo.Where(m => m.GUID == id).ToListAsync();
if (Fields == null)
{
return NotFound();
}
return Page();
}
public async Task<IActionResult> OnPostAsync()
{
if (!ModelState.IsValid)
{
return Page();
}
foreach (var p in Fields) // In this approach Fields shows as count=0
{
_context.Attach(p.Value).State = EntityState.Modified;
}
_context.Attach(Fields).State = EntityState.Modified; // In this approach Exception: The entity type 'List<FieldInfo>' was not found.
await _context.SaveChangesAsync();            
return RedirectToPage("./Index");
}