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社区首页 >问答首页 >Asp.net MVC ModelState.Clear

Asp.net MVC ModelState.Clear
EN

Stack Overflow用户
提问于 2009-11-21 19:04:10
回答 10查看 116.8K关注 0票数 119

有人能给我一个简洁的定义吗? ModelState在Asp.net MVC中的作用(或者一个链接)。特别是,我需要知道在什么情况下调用ModelState.Clear()是必要的或可取的。

位是开放式的,嗯,...抱歉,我想告诉你我到底在做什么可能会有帮助:

我在一个名为"Page“的控制器上执行了一个编辑操作。当我第一次看到用于更改页面详细信息的表单时,一切都正常加载(绑定到"MyCmsPage“对象)。然后单击一个按钮,该按钮为MyCmsPage对象的一个字段(MyCmsPage.SeoTitle)生成值。它生成fine并更新对象,然后我返回带有新修改的页面对象的操作结果,并期望更新相关的文本框(使用<%= Html.TextBox("seoTitle", page.SeoTitle)%>呈现)……但是遗憾的是,它显示了加载的旧模型的值。

我已经通过使用ModelState.Clear()解决了这个问题,但我需要知道它为什么/如何工作,所以我不是盲目地做它。

PageController:

代码语言:javascript
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[AcceptVerbs("POST")]
public ActionResult Edit(MyCmsPage page, string submitButton)
{
    // add the seoTitle to the current page object
    page.GenerateSeoTitle();

    // why must I do this?
    ModelState.Clear();

    // return the modified page object
     return View(page);
 }

Aspx:

代码语言:javascript
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<%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<MyCmsPage>" %>
....
        <div class="c">
            <label for="seoTitle">
                Seo Title</label>
            <%= Html.TextBox("seoTitle", page.SeoTitle)%>
            <input type="submit" value="Generate Seo Title" name="submitButton" />
        </div>
EN

Stack Overflow用户

发布于 2015-02-18 23:50:30

通常,当您发现自己在与框架标准实践作斗争时,是时候重新考虑您的方法了。在本例中,是指ModelState的行为。例如,当您不想在POST之后使用模型状态时,可以考虑重定向到get。

代码语言:javascript
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[HttpPost]
public ActionResult Edit(MyCmsPage page, string submitButton)
{
    if (ModelState.IsValid) {
        SomeRepository.SaveChanges(page);
        return RedirectToAction("GenerateSeoTitle",new { page.Id });
    }
    return View(page);
}

public ActionResult GenerateSeoTitle(int id) {
     var page = SomeRepository.Find(id);
     page.GenerateSeoTitle();
     return View("Edit",page);
}

编辑以回答文化评论:

下面是我用来处理多文化MVC应用程序的代码。首先是路由处理器子类:

代码语言:javascript
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public class SingleCultureMvcRouteHandler : MvcRouteHandler {
    protected override IHttpHandler GetHttpHandler(RequestContext requestContext)
    {
        var culture = requestContext.RouteData.Values["culture"].ToString();
        if (string.IsNullOrWhiteSpace(culture))
        {
            culture = "en";
        }
        var ci = new CultureInfo(culture);
        Thread.CurrentThread.CurrentUICulture = ci;
        Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture(ci.Name);
        return base.GetHttpHandler(requestContext);
    }
}

public class MultiCultureMvcRouteHandler : MvcRouteHandler
{
    protected override IHttpHandler GetHttpHandler(RequestContext requestContext)
    {
        var culture = requestContext.RouteData.Values["culture"].ToString();
        if (string.IsNullOrWhiteSpace(culture))
        {
            culture = "en";
        }
        var ci = new CultureInfo(culture);
        Thread.CurrentThread.CurrentUICulture = ci;
        Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture(ci.Name);
        return base.GetHttpHandler(requestContext);
    }
}

public class CultureConstraint : IRouteConstraint
{
    private string[] _values;
    public CultureConstraint(params string[] values)
    {
        this._values = values;
    }

    public bool Match(HttpContextBase httpContext,Route route,string parameterName,
                        RouteValueDictionary values, RouteDirection routeDirection)
    {

        // Get the value called "parameterName" from the 
        // RouteValueDictionary called "value"
        string value = values[parameterName].ToString();
        // Return true is the list of allowed values contains 
        // this value.
        return _values.Contains(value);

    }

}

public enum Culture
{
    es = 2,
    en = 1
}

这是我如何布线的路线。在创建路由之后,我在我的子代理(example.com/subagent1、example.com/subagent2等)前面加上了区域性代码。如果您只需要区域性,只需从路由处理程序和路由中删除子代理。

代码语言:javascript
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    public static void RegisterRoutes(RouteCollection routes)
    {

        routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
        routes.IgnoreRoute("Content/{*pathInfo}");
        routes.IgnoreRoute("Cache/{*pathInfo}");
        routes.IgnoreRoute("Scripts/{pathInfo}.js");
        routes.IgnoreRoute("favicon.ico");
        routes.IgnoreRoute("apple-touch-icon.png");
        routes.IgnoreRoute("apple-touch-icon-precomposed.png");

        /* Dynamically generated robots.txt */
        routes.MapRoute(
            "Robots.txt", "robots.txt",
            new { controller = "Robots", action = "Index", id = UrlParameter.Optional }
        );

        routes.MapRoute(
             "Sitemap", // Route name
             "{subagent}/sitemap.xml", // URL with parameters
             new { subagent = "aq", controller = "Default", action = "Sitemap"},  new[] { "aq3.Controllers" } // Parameter defaults
        );

        routes.MapRoute(
             "Rss Feed", // Route name
             "{subagent}/rss", // URL with parameters
             new { subagent = "aq", controller = "Default", action = "RSS"},  new[] { "aq3.Controllers" } // Parameter defaults
        );

        /* remap wordpress tags to mvc blog posts */
        routes.MapRoute(
            "Tag", "tag/{title}",
            new { subagent = "aq", controller = "Default", action = "ThreeOhOne", id = UrlParameter.Optional},  new[] { "aq3.Controllers" }
        ).RouteHandler = new MultiCultureMvcRouteHandler(); ;

        routes.MapRoute(
            "Custom Errors", "Error/{*errorType}",
            new { controller = "Error", action = "Index", id = UrlParameter.Optional},  new[] { "aq3.Controllers" }
        );

        /* dynamic images not loaded from content folder */
        routes.MapRoute(
            "Stock Images",
            "{subagent}/Images/{*filename}",
            new { subagent = "aq", controller = "Image", action = "Show", id = UrlParameter.Optional, culture = "en"},  new[] { "aq3.Controllers" }
        );

        /* localized routes follow */
        routes.MapRoute(
            "Localized Images",
            "Images/{*filename}",
            new { subagent = "aq", controller = "Image", action = "Show", id = UrlParameter.Optional},  new[] { "aq3.Controllers" }
        ).RouteHandler = new MultiCultureMvcRouteHandler();

        routes.MapRoute(
            "Blog Posts",
            "Blog/{*postname}",
            new { subagent = "aq", controller = "Blog", action = "Index", id = UrlParameter.Optional},  new[] { "aq3.Controllers" }
        ).RouteHandler = new MultiCultureMvcRouteHandler();

        routes.MapRoute(
            "Office Posts",
            "Office/{*address}",
            new { subagent = "aq", controller = "Offices", action = "Address", id = UrlParameter.Optional }, new[] { "aq3.Controllers" }
        ).RouteHandler = new MultiCultureMvcRouteHandler();

        routes.MapRoute(
             "Default", // Route name
             "{controller}/{action}/{id}", // URL with parameters
             new { subagent = "aq", controller = "Home", action = "Index", id = UrlParameter.Optional }, new[] { "aq3.Controllers" } // Parameter defaults
        ).RouteHandler = new MultiCultureMvcRouteHandler();

        foreach (System.Web.Routing.Route r in routes)
        {
            if (r.RouteHandler is MultiCultureMvcRouteHandler)
            {
                r.Url = "{subagent}/{culture}/" + r.Url;
                //Adding default culture 
                if (r.Defaults == null)
                {
                    r.Defaults = new RouteValueDictionary();
                }
                r.Defaults.Add("culture", Culture.en.ToString());

                //Adding constraint for culture param
                if (r.Constraints == null)
                {
                    r.Constraints = new RouteValueDictionary();
                }
                r.Constraints.Add("culture", new CultureConstraint(Culture.en.ToString(), Culture.es.ToString()));
            }
        }

    }
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页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接:

https://stackoverflow.com/questions/1775170

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