Question

我已实施了一个MVC延伸方案,以安排我申请中的数字。依据的是。页: 1

public static MvcHtmlString DecimalBoxFor<TModel>(this HtmlHelper<TModel> html, Expression<Func<TModel, double?>> expression, string format, object htmlAttributes = null)
{
    var name = ExpressionHelper.GetExpressionText(expression);   
    double? dec = expression.Compile().Invoke(html.ViewData.Model);
    var value = dec.HasValue ? (!string.IsNullOrEmpty(format) ? dec.Value.ToString(format) : dec.Value.ToString()): "";
    return html.TextBox(name, value, htmlAttributes);
}

当我打电话给Razor syntax以下线时

@Html.DecimalBoxFor(model => Model.PointAttributes[i].Data.Y,"0.000", new { @class = "span1 number" })

我有一个例外,因为我延期时的变称是空洞。我已尝试将“老姓”线改为此线,但只给我Y的财产名称,而不是整个模式。 PointAttributes [i]. 数据.Y:我需要将模型重新归结到MVC。

var name = ((expression.Body is MemberExpression ?((MemberExpression)expression.Body).Member : ((MemberExpression)((UnaryExpression)expression.Body).Operand).Member)).Name;

Answer 1

这是众所周知的行为。我用自己的版本(ExpressionHelper处理该具体案件。现在有两种选择:

利用NuGet一揽子计划:

Install-Package Mariuzzo.Web.Mvc.Extras

Or Just grab The source Code of the above expressionHelper, and glue it into You project.

Answer 2

利用这一职能:

    static public string GetExpressionText(LambdaExpression p)
    {
        if (p.Body.NodeType == ExpressionType.Convert || p.Body.NodeType == ExpressionType.ConvertChecked)
        {
            p = Expression.Lambda(((UnaryExpression)p.Body).Operand,
                p.Parameters);
        }
        return ExpressionHelper.GetExpressionText(p);
    }

Answer 3

此处为:

    public static void AddModelError<TModel>(this ModelStateDictionary state, Expression<Func<TModel, object>> expression, string message)
    {
        LambdaExpression lambdaExpression = null;
        string fieldName = string.Empty;

        if (expression.Body.NodeType == ExpressionType.Convert || expression.Body.NodeType == ExpressionType.ConvertChecked)
        {
            lambdaExpression = Expression.Lambda(((UnaryExpression)expression.Body).Operand, expression.Parameters);
            fieldName = ExpressionHelper.GetExpressionText(lambdaExpression);
        } else {
            fieldName = ExpressionHelper.GetExpressionText(expression);
        }

        state.AddModelError(fieldName, message);
    }

这是一种更紧凑的办法,可能是一个更好的解决办法:

https://stackoverflow.com/a/12689563/951001

Answer 4

如果你不使用不可否认的类型,就会放弃,那么看来是行之有效的(即删除?) 过了两倍,或像我的案件一样。 So

Expression<Func<TModel, double?>>

......

Expression<Func<TModel, double>>.

如果你以不可否认的类型通过,你就会看到,这一表述在它中具有转变功能,似乎就是问题。我确信,与我一样,你也有兴趣如何使这一职能成为无效的类型。

Answer 5

我知道这段话已经结束,但为了记录在案;

That s better handled by a template so you can specify what datatype you are using in the model and how it is represented in the template (single responsability). Also you won t need to modify the MVC framework.

出生日期: 1

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