Question

我正在使用ASP.NET MVC。我有父母：

public class ReportFilterBuilderStruct
{
    public string PropName { get; set; }
    public string ClassName { get; set; }
    public string SubListName { get; set; }
    //public virtual string SecondaryPropName { get; set; }

    public ReportFilterBuilderStruct(string inpPropName, string inpClassName, string inpSubListName)
    {
        PropName = inpPropName;
        ClassName = inpClassName;
        SubListName = inpSubListName;
    }
}

还有一个孩子：

public class DateReportFilterBuilderStruct : ReportFilterBuilderStruct
{
    public string SecondaryPropName { get; set; }

    public DateReportFilterBuilderStruct(string inpPropName, string inpSecondaryPropName, string inpClassName, string inpSubListName) : base(inpPropName, inpClassName, inpSubListName)
    {
        SecondaryPropName = inpSecondaryPropName;
    }
}

}

我将在视图中使用它来存储有关我的模型类属性的一些数据。 editorListProp将同时存储ReportFilterBuilderStruct和DateReportFilterBuilderStruct，这就是为什么它是父类对象的List。

var editorListProp = new List<NTStock.Models.ReportFilterBuilderStruct>();

现在我想访问它们：

if (subItem.GetType() == typeof(NTStock.Models.ReportFilterBuilderStruct))
{
    <div class="row align-items-center">
        @Html.DisplayName(subItem.PropName)
    </div>
    <div class="row align-items-center  mb-2">
        @Html.Editor(subItem.PropName, "", new { htmlAttributes = new { @class = subItem.ClassName } })
    </div>
}
else
{
    <div class="row align-items-center">
        @Html.DisplayName(subItem.PropName)
    </div>
    <div class="row align-items-center mb-2">
        <div class="col-6">
            From:
            @Html.Editor(subItem.PropName, "", new { htmlAttributes = new { @class = subItem.ClassName } })
        </div>
        <div class="col-6">
            Till:
            @Html.Editor(subItem.SecondaryPropName, "", new { htmlAttributes = new { @class = subItem.ClassName } })
        </div>
    </div>
}

重点是，我无法访问SecondaryPropName，即使我确保当前的subItem确定类型为DateReportFilterBuilderStruct。

Answer 1

您必须将Long投射到subItem，例如：

DateReportFilterBuilderStruct

Answer 2

这种方法适用于像Python这样的动态类型语言，但不适用于C＃。您的列表属于List<ReportFilterBuilderStruct>类型。当您从列表中访问项目时，例如list[0]，即使您在ReportFilterBuilderStruct存储DateReportFilterBuilderStruct并且GetType()正确返回DateReportFilterBuilderStruct，也会返回else类型的对象。

在DateReportFilterBuilderStruct分支中，您首先必须将项目转换为else { @{ var dateReport = (DateReportFilterBuilderStruct)subItem; } <div class="row align-items-center"> @Html.DisplayName(dateReport.PropName) </div> <div class="row align-items-center mb-2"> <div class="col-6"> From: @Html.Editor(dateReport.PropName, "", new { htmlAttributes = new { @class = dateReport.ClassName } }) </div> <div class="col-6"> Till: @Html.Editor(dateReport.SecondaryPropName, "", new { htmlAttributes = new { @class = dateReport.ClassName } }) </div> </div> }：

document.querySelectorAll('math :not([style*="display:none"])');

C＃从Parent Collection项中获取子属性

2 个答案: