ASP.NET Core 6 MVC点击搜索按钮后如何保留文本框值

下面提供几种可行的解决方法，按需选择：

方法1：通过 ViewBag/ViewData 传递搜索参数 #

修改控制器代码 #

在返回视图前，将搜索参数存入ViewBag：

public ActionResult Index(string name, string email)
{
    var emp = _employeeRepository.GetEmployees();

    if (!string.IsNullOrEmpty(name))
    {
        emp = emp.Where(x => x.FName.ToLower().Contains(name.ToLower()) || x.LName.ToLower().Contains(name.ToLower())).ToList();
    }

    if (!string.IsNullOrEmpty(email))
    {
        emp = emp.Where(x => x.Email.Contains(email)).ToList();
    }

    // 传递搜索参数到视图
    ViewBag.SearchName = name;
    ViewBag.SearchEmail = email;

    return View(emp);
}

修改视图代码 #

给输入框添加value属性，绑定ViewBag中的值：

<form class="d-flex" asp-action="Index" asp-controller="Employee">
    <input name="name" class="form-control" type="search" placeholder="Name" aria-label="Search" value="@ViewBag.SearchName" />
    <input name="email" class="form-control" type="search" placeholder="Email" aria-label="Search" value="@ViewBag.SearchEmail" />
    <button class="btn btn-dark" type="submit">Search</button>
</form>

方法2：使用强类型视图模型（推荐） #

这种方式更符合MVC的架构设计，便于维护和扩展。

创建视图模型类 #

public class EmployeeSearchViewModel
{
    public string Name { get; set; }
    public string Email { get; set; }
    public List<Employee> Employees { get; set; }
}

修改控制器代码 #

实例化视图模型并赋值，将其传递给视图：

public ActionResult Index(string name, string email)
{
    var emp = _employeeRepository.GetEmployees();

    if (!string.IsNullOrEmpty(name))
    {
        emp = emp.Where(x => x.FName.ToLower().Contains(name.ToLower()) || x.LName.ToLower().Contains(name.ToLower())).ToList();
    }

    if (!string.IsNullOrEmpty(email))
    {
        emp = emp.Where(x => x.Email.Contains(email)).ToList();
    }

    var viewModel = new EmployeeSearchViewModel
    {
        Name = name,
        Email = email,
        Employees = emp
    };

    return View(viewModel);
}

修改视图代码 #

指定视图模型，并绑定输入框的value：

@model EmployeeSearchViewModel

<form class="d-flex" asp-action="Index" asp-controller="Employee">
    <input name="name" class="form-control" type="search" placeholder="Name" aria-label="Search" value="@Model.Name" />
    <input name="email" class="form-control" type="search" placeholder="Email" aria-label="Search" value="@Model.Email" />
    <button class="btn btn-dark" type="submit">Search</button>
</form>

<!-- 渲染员工列表示例 -->
@foreach (var employee in Model.Employees)
{
    <div>@employee.FName @employee.LName - @employee.Email</div>
}

方法3：直接读取请求查询参数（快捷方式） #

无需修改控制器，直接在视图中读取URL的查询字符串：

<form class="d-flex" asp-action="Index" asp-controller="Employee">
    <input name="name" class="form-control" type="search" placeholder="Name" aria-label="Search" value="@Request.Query["name"]" />
    <input name="email" class="form-control" type="search" placeholder="Email" aria-label="Search" value="@Request.Query["email"]" />
    <button class="btn btn-dark" type="submit">Search</button>
</form>

内容的提问来源于stack exchange，提问作者Rahul Aggarwal