如何获得一个项目的列表中的一个关键的ModelState [英] How to get a ModelState key of an item in a list

问题描述

问题

我有用户可编辑的字段列表。当模型被提交我要检查，如果这项目是有效的。我不能用数据符号，因为每个领域都有不同的验证过程，我不会知道，直到运行时。如果验证失败我使用 ModelState.AddModelError（字符串键，字符串错误），其中最关键的是你要的错误信息添加到HTML元素的名称。既然有字段列表，剃刀生成的HTML项目名称是像字段[0] .DisplayName 。我的问题是有没有方法或方式来获得生成的HTML名称从视图模型的关键？

尝试性解决方案

我试过的toString（）为没有运气的主要手段。我还通过的HtmlHelper 类看了，但我没有看到任何有用的方法。

code段

视图模型

 公共类CreateFieldsModel
{
    公共TemplateCreateFieldsModel（）
    {
        FreeFields =新的List＆LT; FieldModel＆GT;（）;
    }    [HiddenInput（DisplayValue = FALSE）]
    公众诠释ID {搞定;组; }    公众的IList＆LT; TemplateFieldModel＆GT; FreeFields {搞定;组; }
    公共类TemplateFieldModel
    {
        [显示（NAME =Dispay名称）]
        公共字符串显示名称{搞定;组; }        [需要]
        [显示（名称=田）
        公众诠释FieldTypeID {搞定;组; }
    }
}
 

控制器

 公众的ActionResult CreateFields（CreateFieldsModel模型）
{
    如果（！ModelState.IsValid）
    {
        //我在哪里从视图模型的关键？
        ModelState.AddModelError（model.FreeFields [0]，测试错误）;
        返回查看（模型）;
    }
}
 

解决方案

在源$ C ​​$ C周围挖后，我已经找到了解决方案。有一类称为防爆pressionHelper 用于生成字段的HTML名称时， EditorFor（）被调用。在防爆pressionHelper 类有一个方法 GETEX pressionText（）返回一个字符串，它是该HTML元素的名称。下面是如何使用它...

 的for（int i = 0; I＆LT; model.FreeFields.Count（）;我++）
{
    //生成该项目的前pression
    防爆pression＆LT;＆Func键LT; CreateFieldsModel，串＆GT;＆GT;前pression = X =＆GT; x.FreeFields [I] .value的;
    //获取我们的HTML输入项目名称
    字符串键=前pressionHelper.GetEx pressionText（如pression）;
    //添加一条错误消息，该项目
    ModelState.AddModelError（键，错误！）;
}如果（！ModelState.IsValid）
{
    返回查看（模型）;
}
 

Problem

I have a list of fields that the user can edit. When the model is submitted I want to check if this items are valid. I can't use data notations because each field has a different validation process that I will not know until runtime. If the validation fails I use the ModelState.AddModelError(string key, string error) where the key is the name of the html element you want to add the error message to. Since there are a list of fields the name that Razor generates for the html item is like Fields[0].DisplayName. My question is there a method or a way to get the key of the generated html name from the view model?

Attempted Solution

I tried the toString() method for the key with no luck. I also looked through the HtmlHelper class but I didn't see any helpful methods.

Code Snippet

View Model

public class CreateFieldsModel
{
    public TemplateCreateFieldsModel()
    {
        FreeFields = new List<FieldModel>();
    }

    [HiddenInput(DisplayValue=false)]
    public int ID { get; set; }

    public IList<TemplateFieldModel> FreeFields { get; set; }


    public class TemplateFieldModel
    {
        [Display(Name="Dispay Name")]
        public string DisplayName { get; set; }

        [Required]
        [Display(Name="Field")]
        public int FieldTypeID { get; set; }
    }
}

Controller

public ActionResult CreateFields(CreateFieldsModel model)
{
    if (!ModelState.IsValid)
    {
        //Where do I get the key from the view model?
        ModelState.AddModelError(model.FreeFields[0], "Test Error");
        return View(model);
    }
}

解决方案

After digging around in the source code I have found the solution. There is a class called ExpressionHelper that is used to generate the html name for the field when EditorFor() is called. The ExpressionHelper class has a method called GetExpressionText() that returns a string that is the name of that html element. Here is how to use it ...

for (int i = 0; i < model.FreeFields.Count(); i++)
{
    //Generate the expression for the item
    Expression<Func<CreateFieldsModel, string>> expression = x => x.FreeFields[i].Value;
    //Get the name of our html input item
    string key = ExpressionHelper.GetExpressionText(expression);
    //Add an error message to that item
    ModelState.AddModelError(key, "Error!");
}

if (!ModelState.IsValid)
{
    return View(model);
}

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