当模型状态在回发时有效时,文本框将恢复为旧值

Question

也许我错过了一些东西但是当我有一个回复相同动作的表单时,文本框值会恢复为旧值.以下示例应在每个POST的文本框中增加值.这不会发生,模型上的值会增加并且模型有效.

但是,如果我清除了HttpPost Action中的模型状态(代码中的注释),一切都按预期工作.

我错过了什么吗？

这是代码:

模型:

public class MyModel
{
    public int MyData { get; set; }
}

视图:

<%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" 
Inherits="System.Web.Mvc.ViewPage<MvcApplication1.Models.MyModel>" %>

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
<% using (Html.BeginForm()) {%>
    <%: Html.TextBoxFor(m => m.MyData)%>   (<%: Model.MyData%>)
                  <%: Html.ValidationMessageFor(m => m.MyData) %> <br />
    State :<%: ViewData["State"] %> <br />
    <input type="submit" />
<% } %>
</asp:Content>

控制器:

public class HomeController : Controller
{
    [HttpGet]
    public ActionResult Index()
    {
        return View(new MyModel { MyData = 0 });
    }

    [HttpPost]
    public ActionResult Index(MyModel myModel)
    {
        // ModelState.Clear();
        ViewData["State"] = "invalid";
        if (ModelState.IsValid)
            ViewData["State"] = "Valid";

        var model = new MyModel { MyData = myModel.MyData + 1 };
        return View(model);
    }

}

Answer 1

我刚刚在网上找到了答案.

诀窍是在返回Model之前清除ModelState

[HttpPost]
public ActionResult Index(MyModel myModel)
{
    // ModelState.Clear();
    ViewData["State"] = "invalid";
    if (ModelState.IsValid)
        ViewData["State"] = "Valid";

    var model = new MyModel { MyData = myModel.MyData + 1 };

    ModelState.Clear();

    return View(model);
}

有关详细信息,请阅读这2篇文章

http://forums.asp.net/p/1527149/3687407.aspx

Asp.net MVC ModelState.Clear