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我试图获取与数组中的实例关联的元数据。我已经定义了一个在我的视图中调用的HtmlHelper扩展。我正在尝试创建一个帮助程序来显示模型列表和它们的错误消息。为特定实例获取ModelMetadata
@model Domain.Models.Customer
@this.Html.Example(m => m.Orders)
下面是这个实现我的助手
public static class HtmlHelperExtensions
{
public static IHtmlString Example<TModel, TInstance>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TInstance[]>> expression)
{
var instanceProvider = expression.Compile();
var instances = instanceProvider.Invoke(helper.ViewData.Model);
if(instances != null)
{
var properties = typeof (TInstance).GetProperties();
for(var i = 0; i < instances.Length; i++)
{
var instanceExpression = Expression.ArrayIndex(expression.Body, Expression.Constant(i));
foreach(var info in properties)
{
var propertyExpression = Expression.Property(instanceExpression, info);
// How can i get access to the ModelMetadata
ModelMetadata.FromStringExpression(propertyExpression.ToString(), helper.ViewData);
// To get the model state we need the following...
var text = ExpressionHelper.GetExpressionText(Expression.Lambda(propertyExpression));
var fieldName = helper.ViewData.TemplateInfo.GetFullHtmlFieldName(text);
ModelState state;
if(helper.ViewData.ModelState.TryGetValue(fieldName, out state))
{
// Output errors....
}
}
}
}
return MvcHtmlString.Empty;
}
}
的使用下面的领域类
public class Customer
{
public Order[] Orders { get; set; }
}
public class Order
{
public string Description { get; set; }
}