當我嘗試從編輯頁面的資料中獲取資料時，它向我顯示以下錯誤：
所以我正在建立一個網站，當用戶可以編輯他的橫幅資料時，我想在其中實作一個編輯橫幅表單。
這就是我提出的問題，當我運行代碼時，它總是回傳為null.
這是我的控制器：
[HttpGet]
public ActionResult EditBanner(int id)
{
var abd = (from a in _db.Banner
where id == a.BannerId
select a).FirstOrDefault();
return View(abd);
}
[HttpPost]
public ActionResult UpdateBannerDatas(BannerViewModels bnrupdate)
{
var bnrdata = _db.Banner.Where(x => x.BannerId == bnrupdate.BannerId).FirstOrDefault();
if (bnrdata != null)
{
bnrdata.BannerTitle = bnrupdate.BannerTitle;
bnrdata.BannerUrl = bnrupdate.BannerUrl;
bnrdata.BannerIndex = bnrupdate.BannerIndex;
bnrdata.BannerDescription = bnrupdate.BannerDescription;
bnrdata.BannerIndex = bnrupdate.BannerIndex;
_db.SaveChanges();
}
return Redirect("BannerDetails");
}
這是我的視圖模型：
using Microsoft.AspNetCore.Http;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using SZGMC.Web.Models;
namespace SZGMC.Web.Areas.Admin.ViewModels
{
public class BannerViewModels
{
public int BannerId { get; set; }
public string BannerTitle { get; set; }
public string BannerDescription { get; set; }
public string BannerImg { get; set; }
public IFormFile BannerImg1 { get; set; }
public string BannerUrl { get; set; }
public string BannerIndex { get; set; }
public int? BMasterId { get; set; }
public byte? IsDeleted { get; set; }
public virtual BannerMaster BMaster { get; set; }
}
}
這是我的模型：
using System;
using System.Collections.Generic;
// Code scaffolded by EF Core assumes nullable reference types (NRTs) are not used or disabled.
// If you have enabled NRTs for your project, then un-comment the following line:
// #nullable disable
namespace SZGMC.Web.Models
{
public partial class Banner
{
public int BannerId { get; set; }
public string BannerTitle { get; set; }
public string BannerDescription { get; set; }
public string BannerImg { get; set; }
public string BannerUrl { get; set; }
public string BannerIndex { get; set; }
public int? BMasterId { get; set; }
public byte? IsDeleted { get; set; }
public virtual BannerMaster BMaster { get; set; }
}
}
這是我的看法：
<form asp-controller="Home" asp-action="UpdateBannerDatas" enctype="multipart/form-data" method="post">
<div id="main-content">
<div class="container-fluid">
<!-- Page header section -->
<div class="block-header">
<div class="row clearfix">
<div class="col-lg-6 col-md-5 col-sm-12">
<h1>Hi, Welcomeback!</h1>
<span>You can edit banner here</span>
</div>
<div class="col-xl-6 col-md-7 col-sm-12 text-md-right">
<div class="d-flex align-items-center justify-content-md-end mt-4 mt-md-0 flex-wrap vivify pullUp delay-550">
<div class="mb-3 mb-xl-0 ">
<a asp-action="BannerDetails" class="btn btn-dark">Banner List</a>
</div>
</div>
</div>
</div>
</div>
<div class="row clearfix">
<div class="col-12">
<div class="card">
<div class="body">
<div class="header">
<h2><strong>Enter Banner Details</strong></h2>
</div>
<br />
<input asp-for="BannerId" type="hidden" />
<div class="row">
<div class="col-12">
<div class="form-group c_form_group">
<div class="input-group">
<div class="input-group-prepend">
<span class="input-group-text"></span>
</div>
<input type="text" class="form-control" asp-for="BannerTitle" placeholder="Banner Title" aria-label="bannertitle" aria-describedby="basic-addon1">
</div>
</div>
</div>
</div>
<div class="row">
<div class="col-6">
<div class="form-group c_form_group">
<label>Banner Description</label>
<div class="input-group">
<textarea class="form-control" asp-for="BannerDescription" aria-label="Banner Description" rows="6"></textarea>
</div>
</div>
</div>
<div class="col-6">
<div class="drop-zone">
<span class="drop-zone__prompt">Drop file here or click to upload</span>
<input type="file" asp-for="BannerImg1" name="myFile" class="drop-zone__input" accept="image/*" data-allowed-file-extensions='["jpg", "png" , "jpeg"]' required>
</div>
</div>
</div>
<div class="row">
<div class="col-6">
<div class="form-group c_form_group">
<div class="input-group">
<div class="input-group-prepend">
<span class="input-group-text"></span>
</div>
<input type="text" class="form-control" asp-for="BannerIndex" placeholder="Banner Index" aria-label="bannerindex" aria-describedby="basic-addon1">
</div>
</div>
</div>
<div class="col-6">
<div class="form-group c_form_group">
<div class="input-group">
<div class="input-group-prepend">
<span class="input-group-text"></span>
</div>
</div>
</div>
</div>
</div>
<div class="mb-2" align="center">
<button type="submit" class="btn btn-success btn-round">Edit Banner</button>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</form>
當我嘗試在瀏覽器中編輯資料時，它拋出例外，在資料庫中我有價值，但是當我嘗試獲取資料時，它顯示錯誤。
提前感謝大家的任何幫助或建議。
uj5u.com熱心網友回復：
根據錯誤訊息，有必要傳遞BannerViewModels實體而不是Banner物體：
public ActionResult EditBanner(int id)
{
var abd = _db.Banner.Where(a => a.BannerId == id)
.Select(b => new BannerViewModels()
{
BannerId = b.BannerId,
BannerTitle = b.BannerTitle,
BannerDescription = b.BannerDescription,
BannerImg = b.BannerImg,
BannerUrl = b.BannerUrl,
BannerIndex = b.BannerIndex,
BMasterId = b.BMasterId,
IsDeleted = b.IsDeleted
})
.FirstOrDefault();
return View(abd);
}
將物體作為資料模型傳遞給視圖是個壞主意。
請參閱以下帖子：為什么在 MVC 中將物體作為模型傳遞不是一個好主意？
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標籤：C＃ 网 asp.net-mvc asp.net 核心