根据另一个属性的值获取属性的描述

Question

请考虑此准则:

[ShowFieldByRole(User1 = false, User2 = false, User3 = true)]
[FieldName(Name = "Desciption1")]
public string G_Sum{set; get;}
[ShowFieldByRole(User1 = false, User2 = false, User3 = false)]
[FieldName(Name = "Desciption2")]
public string G_Sum2{set; get;}
[ShowFieldByRole(User1 = false, User2 = false, User3 = true)]
[FieldName(Name = "Desciption3")]
public string G_Sum3{set; get;}

我创建了两个自定义属性类，现在我想获得所有的描述(的值)Name属性(FieldName属性)的属性(User3=true属性)与反射。

例如，根据上面的代码，我想得到Description2,Descriptio3，因为它们的User3等于true

我该怎么做?

感谢

---

编辑1)

我写了这段代码，它返回Description2,Descriptio3:

var My = typeof(ClassWithAttr).GetProperties(BindingFlags.Instance | BindingFlags.Public)
                          .Where(p => p.GetCustomAttributes(typeof(FieldName), true)
                          .Where(ca => ((ShowFieldByRole)ca).User3 == true)
                          .Any()).Select(p=>p.GetCustomAttributes(typeof(FieldName),true).Cast<FieldName>().FirstOrDefault().Name);

现在我想返回[PropertyName , Name]当我这样写代码:

    var My = typeof(ClassWithAttr).GetProperties(BindingFlags.Instance | BindingFlags.Public)
                          .Where(p => p.GetCustomAttributes(typeof(FieldName), true)
                          .Where(ca => ((ShowFieldByRole)ca).User3 == true)
                          .Any()).ToDictionary(f => f.Name, h=>h.GetValue(null).ToString());

但是我得到了这个错误:

无法将lambda表达式转换为"System.Collections.Generic"类型。因为它不是委托类型

问题在哪里?

Answer 1

在上一个示例中，f和h都是PropertyInfo

正确的代码是

var dictionay = (from propertyInfo in typeof (ClassWithAttr).GetProperties(BindingFlags.Instance | BindingFlags.Public)
                 where propertyInfo.GetCustomAttributes(typeof (ShowFieldByRoleAttribute), true).Cast<ShowFieldByRoleAttribute>().Any(a => a.User3)
                 from FieldNameAttribute fieldName in propertyInfo.GetCustomAttributes(typeof (FieldNameAttribute), true)
                 select new { PropertyName = propertyInfo.Name, FiledName = fieldName.Name })
    .ToDictionary(x => x.PropertyName, x => x.FiledName);

UPD使用方法链

var dictionay = typeof (ClassWithAttr).GetProperties(BindingFlags.Instance | BindingFlags.Public)
    .Where(p => p.GetCustomAttributes(typeof (ShowFieldByRoleAttribute), true).Cast<ShowFieldByRoleAttribute>().Any(a => a.User3))
    .SelectMany(p => p.GetCustomAttributes(typeof (FieldNameAttribute), true).Cast<FieldNameAttribute>(),
                (p, a) => new { PropertyName = p.Name, FiledName = a.Name })
    .ToDictionary(a => a.PropertyName, a => a.FiledName);