存储更新，插入或删除语句影响了意外数量的行（0）。实体可能已修改或删除

Question

在尝试保存编辑页面时，我发现了以下实体框架错误，

   "Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded."

这是我的编辑控制器

 [HttpPost]
        public ActionResult Edit(RESULT results)
        {
           if (ModelState.IsValid)
            {
                _context.Entry(results).State = EntityState.Modified;
                _context.SaveChanges();
                return RedirectToAction("Details");
            }
            return View(results);
        }

，我需要更新多个行（仅结果列值）

，我检查了网站中的解决方案

，我添加了主密钥ID列，请参见图像：

这是编辑视图代码：

<table class="table">
    <tr>
        <td>
            @Html.DisplayNameFor(model => model.FirstOrDefault().ID)
        </td>
        <td>
            @Html.DisplayNameFor(model => model.FirstOrDefault().custid)
        </td>
       
        <td>
            @Html.DisplayNameFor(model => model.FirstOrDefault().TESTID)
        </td>
        <td>
            @Html.DisplayNameFor(model => model.FirstOrDefault().LabTest.TestName)
        </td>
        
        <td>
            @Html.DisplayNameFor(model => model.FirstOrDefault().RESULT1)
        </td>
       
    </tr>
      @for (int i = 0; i < Model.Count; i++)
      {
          <tr>
               
              <td>
                  @Html.TextBox("RESULTS[" + @i + "].ID", Model[i].ID, new { @readonly = "readonly" })

              </td>
              <td>
                  @Html.TextBox("RESULTS[" + @i + "].custid", Model[i].custid, new { @readonly = "readonly" })
                  
              </td>
               <td>
                  @Html.TextBox("RESULTS[" + @i + "].TESTID", Model[i].TESTID, new { @readonly = "readonly" })
              </td>
              <td>
                  @Html.TextBox("LabTest[" + @i + "].TestName", Model[i].LabTest.TestName, new { @readonly = "readonly" })
              </td>
             
              <td>
                  @Html.TextBox("RESULTS[" + @i + "].RESULT1", Model[i].RESULT1)
              </td>
            
          </tr>
      }
</table>  
<div class="form-group">
        <div class="col-md-offset-2 col-md-10" style="margin:100px;">
            <input type="submit" value="Save" class="btn btn-danger" />
        </div>
    </div> 

我的代码中缺少什么，请我需要您的帮助？

Answer 1

在您的控制器操作上，参数应为列表。您需要迭代并更新。

    [HttpPost]
    public ActionResult Edit(List<RESULT> results)
    {
       if (ModelState.IsValid)
        {
            foreach(var item in results)
            {
                var model =_context.Find(item.ID);
                if(model != null) {  
                   model.TestID = item.TestID;
                   model.TestName = item.TestName;
                   //update columns you want to update
                   _context.SaveChanges();
                }
            }
            ViewBag.Message = "Updated Successfully";
            return RedirectToAction("Details");
        }
        return View(results);
    }

看法

@if(ViewBag.Message != null){
   @ViewBag.Message
}

Answer 2

我找到了解决方案，我将代码更改为以下：

编辑控制器代码：

 public ActionResult Edit(List<RESULT> list)
        {
           if (ModelState.IsValid)
            {
                using (db_Entities db = new db_Entities())
                {
                    foreach (var i in list)
                    {
                        var c = db.RESULTS.Where(a => a.ID.Equals(i.ID)).FirstOrDefault();
                        if (c != null)
                        {
                            c.RESULT1 = i.RESULT1;
                        }
                    }
                    db.SaveChanges();
                    
                }
             //   ViewBag.Message("Updated Successfully");
                return View(list);
            }
            else
            {
              //  ViewBag.Message("Failed ! Please try again");
                return View(list);
            }        

        }

编辑视图代码：

<table class="table">
    <tr>
        
        <td> @Html.DisplayNameFor(model => model.FirstOrDefault().custid) </td>
        <td> @Html.DisplayNameFor(model => model.FirstOrDefault().TESTID) </td>
        <td> @Html.DisplayNameFor(model => model.FirstOrDefault().LabTest.TestName) </td>
        <td> @Html.DisplayNameFor(model => model.FirstOrDefault().APPROVED_BY) </td>
        <td> @Html.DisplayNameFor(model => model.FirstOrDefault().APPROVED_DATE) </td>
        <td> @Html.DisplayNameFor(model => model.FirstOrDefault().RESULT1) </td>
       
    </tr>
      @for (int i = 0; i < Model.Count; i++)
      {
          <tr>
           
              <td>@Html.HiddenFor(model => model[i].ID)</td>
              <td>@Html.EditorFor(model => model[i].custid)</td>
              <td>@Html.EditorFor(model => model[i].TESTID)</td>
              <td>@Html.EditorFor(model => model[i].LabTest.TestName)</td>
              <td>@Html.EditorFor(model => model[i].APPROVED_BY)</td>
              <td>@Html.EditorFor(model => model[i].APPROVED_DATE)</td>
              <td>@Html.EditorFor(model => model[i].RESULT1)</td>
              
            
          </tr>
      }
</table>
 
    <div class="form-group">
        <div class="col-md-offset-2 col-md-10" style="margin:100px;">
            <input type="submit" value="Save" class="btn btn-danger" />
           </div>
    </div>
    @*<p style="color:green;font-size:16px;">
        @ViewBag.Message
    </p>*@

Answer 3

基于@RAM Anugandula逻辑进行了修改，我们可以在循环完成后保存数据，因为对象是参考类型，我们可以保存修改整个对象后

[HttpPost]
public ActionResult Edit(List<RESULT> Input)
{
   if (ModelState.IsValid)
    {
        foreach(var item in Input)
        {
            var model =_context.Yourdbsetentity.Find(item.ID);
            If(model!=null){
            model.TestID = item.TestID;
            model.TestName = item.TestName;
            //update columns you want to update
             }else{
               model=new RESULT();
               model.TestID = item.TestID;
               model.TestName = item.TestName;
              //Create columns you want to update
             _context.Yourdbsetentity.add(model)
           }
        }
            _context.SaveChanges();
        return RedirectToAction("Details");
    }
    return View(results);
}