更新时如何将所选项目添加到 SelectList答案

【问题标题】：How to add selected Item to SelectList when updating更新时如何将所选项目添加到 SelectList
【发布时间】：2021-08-03 09:52:23
【问题描述】：

我一直在网上搜索，当用户想要更新员工时，我找不到选择所选部门的方法。

我希望选择值obj.Department定义选择列表的顺序listItems我可以发送除部门之外的所有其他内容。

 public IActionResult EditDetail(Employee obj)

        {
            var viewModel = new Employee
            {
                EmployeeId = obj.EmployeeId,
                Name = obj.Name,
                Surname = obj.Surname,
                DateOfBirth = obj.DateOfBirth,
                Department = obj.Department
            };


            var listItems = new List<SelectListItem> {
            new SelectListItem {Text = "Business", Value = "1"},
            new SelectListItem {Text = "Information Technology", Value = "2"},
            new SelectListItem {Text = "Human Capital", Value = "3"}
            };

            
            ViewBag.listItems = listItems;

            return View(viewModel);
        }

html

  <select class="form-control" style="width:450px" asp-for="Department" asp-items="ViewBag.listItems">

【问题讨论】：

标签： c# asp.net asp.net-mvc selectlistitem

【解决方案1】：

如果您没有 DepartmentId，则必须通过添加来修复 Employee 类

public class Employee
{
   .....
  public int DepartmentId {get; set;}
  public virtual Department {get; set;}
}

动作

 var viewModel = new Employee
  {
   .....
   DepartmentId = obj.DepartmentId
 };
   
  ......

    return View(viewModel);

//but I don't think that you need  to create viewmodel in your case. 
//you can try

 return View(obj);

查看

 <select class="form-control" style="width:450px" asp-for="DepartmentId" asp-items="ViewBag.listItems">

【讨论】：