MVC更新脚手架字段下拉至

编程问答 2022-06-06

问题描述

Web Dev noob在这里。 我目前正在使用VS2019，并已创建MVC应用程序以向内部用户提供CRUD功能（sql）。 我们有一个CostCentre字段，应该是一个下拉列表，而不是文本输入。

如何更改代码以显示下拉列表而不是文本输入？

这是我的控制器中包含的内容：

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit([Bind(Include = "Magic,EmployeeCode,UserName,Entity,AD_SAM,MSTelNum,CostCentre,SysUser_AD,Sys_User_K8")] EmpCosDim empCosDim)
{
    if (ModelState.IsValid)
    {
        db.Entry(empCosDim).State = EntityState.Modified;
        db.SaveChanges();
        return RedirectToAction("Index");
    }
    return View(empCosDim);
}

我在找对地方吗？

更新 编辑视图cshtml：

@model EmployeeBilling.EmpCosDim
@{
    ViewBag.Title = "Edit";
}

<h2>Edit</h2>

@using (Html.BeginForm())
{
    @Html.AntiForgeryToken()
    
    <div class="form-horizontal">
        <h4>EmpCosDim</h4>
        <hr />
        @Html.ValidationSummary(true,"",new { @class = "text-danger" })
        @Html.HiddenFor(model => model.Magic)

        <div class="form-group">
            @Html.LabelFor(model => model.EmployeeCode,htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.EmployeeCode,new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.EmployeeCode,new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.UserName,htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.UserName,new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.UserName,new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.Entity,htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.Entity,new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.Entity,new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.AD_SAM,htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.AD_SAM,new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.AD_SAM,new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.MSTelNum,htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.MSTelNum,new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.MSTelNum,new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.CostCentre,htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.CostCentre,new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.CostCentre,new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.SysUser_AD,htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.SysUser_AD,new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.SysUser_AD,new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.Sys_User_K8,htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.Sys_User_K8,new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.Sys_User_K8,new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            <div class="col-md-offset-2 col-md-10">
                <input type="submit" value="Save" class="btn btn-default" />
            </div>
        </div>
    </div>
}

<div>
    @Html.ActionLink("Back to List","Index")
</div>

@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

更新 根据您发送的链接添加了ForeignKey，但仍不显示下拉列表。我在这里做了更改：

EmpCosDim.cs

// EmpCosDim.cs :

namespace EmployeeBilling
{
    using System;
    using System.Collections.Generic;
    using System.ComponentModel.DataAnnotations;
    using System.ComponentModel.DataAnnotations.Schema;

    public class EmpCosDim
    {
        public int Magic { get; set; }
        public string EmployeeCode { get; set; }
        public string UserName { get; set; }
        public string Entity { get; set; }
        public string AD_SAM { get; set; }
        public string MSTelNum { get; set; }

        [ForeignKey("ContainingCostCentre")]
        public string CostCentre { get; set; }
        public virtual EmpCosDim ContainingCostCentre { get; set; }

        public string SysUser_AD { get; set; }
        public string Sys_User_K8 { get; set; }
    }
}

更新 因此，我尝试将CostCentre更新为EmpCosDim.cs文件中的列表：

public class EmpCosDim
{
    [Key]
    public int Magic { get; set; }
    public string EmployeeCode { get; set; }
    public string UserName { get; set; }
    public string Entity { get; set; }
    public string AD_SAM { get; set; }
    public string MSTelNum { get; set; }

    public List<SelectCostCentreItem> CostCentre { get; set; }

    public string SysUser_AD { get; set; }
    public string Sys_User_K8 { get; set; }
}

public class SelectCostCentreItem
{
    public string CostCentre { get; set; }
}

但是我的控制器EmpCosDimsController.cs出现错误：

public ActionResult Index()
{
    return View(db.EmpCosDims.ToList());
}

Error

这似乎是因为我替换了：

public string CostCentre { get; set; }

使用

public List<SelectCostCentreItem> CostCentre { get; set; }

如何更新控制器以查看列表并在下拉列表中显示？

解决方法

您的编辑屏幕中CostCentre的下拉列表实际上将显示您要选择的所有CostCentre的列表。该列表在EmpCosDim模型和视图中不可用。您需要构建一个选择列表，然后传递到视图并在视图中进行更改，以获取该列表并显示为下拉列表。 请按照以下步骤-

在“编辑”操作（对于“不获取帖子”操作中）中，这样填充视图包

ViewBag.CostCentre = new SelectList([db.Concetres],["Name"],[empCosDim.CostCentre]);

在这里，您必须用适当的变量/方法替换括号中的项目。对于 选择列表构造函数的第一个是所有成本中心的源/列表， 第二个是要保存为值的EmpCosDim的字段名称 被选中，第三个要显示在EmpCosDim的字段中 下拉菜单，最后一个是您要默认选择的值。

在“编辑”视图中，替换以下代码

<div class="form-group">
    @Html.LabelFor(model => model.CostCentre,htmlAttributes: new { @class = "control-label col-md-2" })
    <div class="col-md-10">
        @Html.EditorFor(model => model.CostCentre,new { htmlAttributes = new { @class = "form-control" } })
        @Html.ValidationMessageFor(model => model.CostCentre,"",new { @class = "text-danger" })
    </div>
</div>

带有下一个代码块

<div class="form-group">
        @Html.LabelFor(model => model.CostCentre,htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.DropDownList("CostCentre",(IEnumerable<SelectListItem>)ViewBag.CostCentre,new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.CostCentre,new { @class = "text-danger" })
        </div>
 </div>
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