Asp.net MVC ModelState.Clear [英] Asp.net MVC ModelState.Clear
问题描述
谁能给我的ModelState在Asp.net MVC中的角色（或一个链接）的简洁的定义。我特别需要有必要或适宜什么情况下叫 ModelState.Clear（）。
位开放式呵呵 ...很抱歉，我想这可能帮助，如果告诉你，我实际上可以做的：
我编辑的一个叫做页控制器的动作。当我第一次看到的形式来改变页面的细节一切加载了罚款（绑定到一个MyCmsPage对象）。然后我点击产生的MyCmsPage对象的字段中的值按钮（ MyCmsPage.SeoTitle ）。它产生罚款和更新对象，我再与新修改的页面对象返回作用的结果，并希望相关文本框（使用渲染＆LT;％= Html.TextBox（seoTitle，page.SeoTitle） ％方式＆gt; ）进行更新......但可惜它显示从已加载的旧模式值
我用 ModelState.Clear（）周围的工作，但我需要知道它是如何工作的，为什么/我不只是做盲目的。
的PageController：
的[AcceptVerbs（POST）]
公众的ActionResult编辑（MyCmsPage页，串提交按钮）
{
//添加seoTitle到当前页面对象
page.GenerateSeoTitle（）; //我为什么一定要这样做呢？
ModelState.Clear（）; //返回修改后的页面对象
返回查看（页）;
}
.aspx的：
＆LT;％@页面语言=C＃的MasterPageFile =〜/查看/共享/的Site.Master继承=System.Web.Mvc.ViewPage＆LT; MyCmsPage＆gt;中％GT;
....
＆LT; DIV CLASS =C＆GT;
＆LT;标签=seoTitle＆GT;
徐标题＆LT; /标签＆gt;
＆所述;％= Html.TextBox（seoTitle，page.SeoTitle）％GT;
＆LT;输入类型=提交值=生成徐标题NAME =提交按钮/＆GT;
＆LT; / DIV＆GT;
我觉得是MVC中的错误。我挣扎着这个问题今天小时。
有鉴于此：
公开的ViewResult SomeAction（SomeModel模型）
{
model.SomeString =一些价值;
返回查看（模型）;
}
该视图与渲染的原始模型，忽略了变化。所以我想，也许它并没有使用相同型号的喜欢我，所以我想是这样的：
公开的ViewResult SomeAction（SomeModel模型）
{
newModel，并向VAR =新SomeModel {SomeString =一些价值};
返回查看（newModel，并向）;
}
和仍然认为呈现的原始模型。有什么奇怪的是，当我把一个断点在视图和检查模型，它有改变的值。但响应流具有旧值。
最后，我发现了同样的工作围绕着你做：
公开的ViewResult SomeAction（SomeModel模型）
{
newModel，并向VAR =新SomeModel {SomeString =一些价值};
ModelState.Clear（）;
返回查看（newModel，并向）;
}
按预期工作。
我不认为这是一个功能，是吧？
Can anyone give me a succinct definition of the role of ModelState in Asp.net MVC (or a link to one). In particular I need to know in what situations it is necessary or desirable to call ModelState.Clear().
Bit open ended huh... sorry, I think it might help if tell you what I'm acutally doing:
I have an Action of Edit on a Controller called "Page". When I first see the form to change the Page's details everything loads up fine (binding to a "MyCmsPage" object). Then I click a button that generates a value for one of the MyCmsPage object's fields (MyCmsPage.SeoTitle). It generates fine and updates the object and I then return the action result with the newly modified page object and expect the relevant textbox (rendered using <%= Html.TextBox("seoTitle", page.SeoTitle)%>) to be updated ... but alas it displays the value from the old model that was loaded.
I've worked around it by using ModelState.Clear() but I need to know why / how it has worked so I'm not just doing it blindly.
PageController:
[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:
<%@ 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>
I think is a bug in MVC. I struggled with this issue for hours today.
Given this:
public ViewResult SomeAction(SomeModel model)
{
model.SomeString = "some value";
return View(model);
}
The view renders with the original model, ignoring the changes. So I thought, maybe it does not like me using the same model, so I tried like this:
public ViewResult SomeAction(SomeModel model)
{
var newModel = new SomeModel { SomeString = "some value" };
return View(newModel);
}
And still the view renders with the original model. What's odd is, when I put a breakpoint in the view and examine the model, it has the changed value. But the response stream has the old values.
Eventually I discovered the same work around that you did:
public ViewResult SomeAction(SomeModel model)
{
var newModel = new SomeModel { SomeString = "some value" };
ModelState.Clear();
return View(newModel);
}
Works as expected.
I don't think this is a "feature," is it?
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