在ASP.NET Core 6 MVC中,要在提交后保持下拉列表的选定值,可以按照以下步骤进行操作:
public class MyViewModel
{
public List Options { get; set; }
public string SelectedOption { get; set; }
}
public class MyController : Controller
{
public IActionResult Index()
{
// 创建下拉列表的数据源
var options = new List
{
new SelectListItem { Value = "1", Text = "Option 1" },
new SelectListItem { Value = "2", Text = "Option 2" },
new SelectListItem { Value = "3", Text = "Option 3" }
};
var viewModel = new MyViewModel
{
// 设置下拉列表的数据源和选定值
Options = options,
SelectedOption = "2"
};
return View(viewModel);
}
[HttpPost]
public IActionResult Index(MyViewModel viewModel)
{
// 在提交后重新设置选定的值
viewModel.Options = new List
{
new SelectListItem { Value = "1", Text = "Option 1" },
new SelectListItem { Value = "2", Text = "Option 2" },
new SelectListItem { Value = "3", Text = "Option 3" }
};
return View(viewModel);
}
}
Html.DropDownListFor
方法来呈现下拉列表,并使用Model.SelectedOption
属性来设置选定值。例如:@model MyViewModel
通过以上步骤,在提交后,下拉列表将保持之前选定的值。