Asp.net mvc 4 ModelState.AddModelError为什么没有ModelState.AddModelSuccess？

ModelState是一个字典对象，它包含模型和模型构建验证的状态

ModelState.AddModelError("MyKey", "My Error Message");   

AddModelError（）

将指定的错误消息添加到与指定键（MyKey）链接的模型状态字典的错误集合中

为什么没有

ModelState.AddModelSucces（“MyKey”、“我的错误消息”）

？谁能告诉我如何在视图中显示成功消息

ModelState.AddModelSucces("MyKey", "My Error Message") ???

---

您可以按照与HTML.ValidationMessageFor相同的行创建HTML帮助程序扩展方法

下面是一个我很快想到的例子，但你可以进一步扩展它。看一看，获得更多的想法

这将输出一个带有css class

字段验证有效的
span
标记

<span class="field-validation-valid">My success message</span>

扩展方法

public static MvcHtmlString ValidationSuccessMessageFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression)
{
    return ValidationSuccessMessageFor(htmlHelper, expression, null, new RouteValueDictionary());
}

public static MvcHtmlString ValidationSuccessMessageFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, string validationMessage)
{
    return ValidationSuccessMessageFor(htmlHelper, expression, validationMessage, new RouteValueDictionary());
}

public static MvcHtmlString ValidationSuccessMessageFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, string validationMessage, object htmlAttributes)
{
    return ValidationSuccessMessageFor(htmlHelper, expression, validationMessage, HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes));
}

public static MvcHtmlString ValidationSuccessMessageFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, string validationMessage, IDictionary<string, object> htmlAttributes)
{
    return ValidationMessageHelper(htmlHelper, ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData), ExpressionHelper.GetExpressionText(expression), validationMessage, htmlAttributes);
}

private static MvcHtmlString ValidationMessageHelper(this HtmlHelper htmlHelper, ModelMetadata modelMetadata, string expression, string validationMessage, IDictionary<string, object> htmlAttributes)
{
    var modelName = htmlHelper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(expression);
        FormContext formContext = htmlHelper.ViewContext.ClientValidationEnabled ? htmlHelper.ViewContext.FormContext : null;

    if (!htmlHelper.ViewData.ModelState.ContainsKey(modelName) && formContext == null)
    {
        return null;
    }

    var modelState = htmlHelper.ViewData.ModelState[modelName];

    if (modelState == null || (modelState != null && (modelState.Errors == null || modelState.Errors.Count > 0)))
    {
        return null;
    }

    var builder = new TagBuilder("span");
    builder.MergeAttributes(htmlAttributes);
    builder.AddCssClass(HtmlHelper.ValidationMessageValidCssClassName);

    if (!String.IsNullOrEmpty(validationMessage))
    {
        builder.SetInnerText(validationMessage);
    }

    return MvcHtmlString.Create(builder.ToString(TagRenderMode.Normal));
}

public static MvcHtmlString ValidationSuccessMessageFor（此HtmlHelper HtmlHelper，表达式）
{
返回ValidationSuccessMessageFor（htmlHelper，表达式，null，new RouteValueDictionary（））；
}
公共静态MvcHtmlString ValidationSuccessMessageFor（此HtmlHelper HtmlHelper、表达式、字符串验证消息）
{
返回ValidationSuccessMessageFor（htmlHelper，表达式，validationMessage，new RouteValueDictionary（））；
}
公共静态MvcHtmlString ValidationSuccessMessageFor（此HtmlHelper HtmlHelper、表达式、字符串验证消息、对象htmlAttributes）
{
返回ValidationSuccessMessageFor（htmlHelper，表达式，validationMessage，htmlHelper.AnonymousObjectToHtmlAttributes（htmlAttributes））；
}
公共静态MvcHtmlString ValidationSuccessMessageFor（此HtmlHelper HtmlHelper、表达式、字符串验证消息、IDictionary htmlAttributes）
{
返回ValidationMessageHelper（htmlHelper、ModelMetadata.FromLambdaExpression（表达式、htmlHelper.ViewData）、ExpressionHelper.GetExpressionText（表达式）、validationMessage、htmlAttributes）；
}
私有静态MVCHTMLSTING ValidationMessageHelper（此HtmlHelper HtmlHelper、模型元数据模型元数据、字符串表达式、字符串验证消息、IDictionary htmlAttributes）
{
var modelName=htmlHelper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName（表达式）；
FormContext FormContext=htmlHelper.ViewContext.ClientValidationEnabled？htmlHelper.ViewContext.FormContext:null；
如果（！htmlHelper.ViewData.ModelState.ContainsKey（modelName）&&formContext==null）
{
返回null；
}
var modelState=htmlHelper.ViewData.modelState[modelName]；
如果（modelState==null | | |（modelState！=null&&（modelState.Errors==null | | modelState.Errors.Count>0）））
{
返回null；
}
var builder=新标记生成器（“span”）；
builder.MergeAttributes（HtmlatAttributes）；
builder.AddCssClass（HtmlHelper.validationMessageValidcsClassName）；
如果（！String.IsNullOrEmpty（validationMessage））
{
builder.SetInnerText（validationMessage）；
}
返回MvcHtmlString.Create（builder.ToString（TagRenderMode.Normal））；
}
根据设计，您只会向模型状态添加错误消息。如果您想要成功消息，只需使用其他视图模型或viewbag即可。@David
ModelState.IsValid
表示布尔值我想知道如何添加成功消息，如
ModelState.AddModelSuccess
很遗憾，此方法不可用？使用类似TempData的方法？这是一个字典集合。@David+1我可以使用
TempData[“key”]
public static MvcHtmlString ValidationSuccessMessageFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression)
{
    return ValidationSuccessMessageFor(htmlHelper, expression, null, new RouteValueDictionary());
}

public static MvcHtmlString ValidationSuccessMessageFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, string validationMessage)
{
    return ValidationSuccessMessageFor(htmlHelper, expression, validationMessage, new RouteValueDictionary());
}

public static MvcHtmlString ValidationSuccessMessageFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, string validationMessage, object htmlAttributes)
{
    return ValidationSuccessMessageFor(htmlHelper, expression, validationMessage, HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes));
}

public static MvcHtmlString ValidationSuccessMessageFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, string validationMessage, IDictionary<string, object> htmlAttributes)
{
    return ValidationMessageHelper(htmlHelper, ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData), ExpressionHelper.GetExpressionText(expression), validationMessage, htmlAttributes);
}

private static MvcHtmlString ValidationMessageHelper(this HtmlHelper htmlHelper, ModelMetadata modelMetadata, string expression, string validationMessage, IDictionary<string, object> htmlAttributes)
{
    var modelName = htmlHelper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(expression);
        FormContext formContext = htmlHelper.ViewContext.ClientValidationEnabled ? htmlHelper.ViewContext.FormContext : null;

    if (!htmlHelper.ViewData.ModelState.ContainsKey(modelName) && formContext == null)
    {
        return null;
    }

    var modelState = htmlHelper.ViewData.ModelState[modelName];

    if (modelState == null || (modelState != null && (modelState.Errors == null || modelState.Errors.Count > 0)))
    {
        return null;
    }

    var builder = new TagBuilder("span");
    builder.MergeAttributes(htmlAttributes);
    builder.AddCssClass(HtmlHelper.ValidationMessageValidCssClassName);

    if (!String.IsNullOrEmpty(validationMessage))
    {
        builder.SetInnerText(validationMessage);
    }

    return MvcHtmlString.Create(builder.ToString(TagRenderMode.Normal));
}