如何获取具有指定名称的DataMemberAttribute的财产? [英] How to get the property that has a DataMemberAttribute with a specified name?
问题描述
我怎样才能得到反思,有一个给定名称的数据成员的属性(假设每个数据成员都有一个唯一的名字)?例如,在C与具有名为P1的数据成员的属性如下$ C $是 PropertyOne
:
[DataContract(NAME =MyContract)
公共类MyContract
{
[数据成员(名称为P1)
公共字符串PropertyOne {获得;组; }
[数据成员(名称为P2)
公共字符串PropertyTwo {获得;组; }
[数据成员(名称为P3)
公共字符串PropertyThree {获得;组; }
}
目前,我有:
字符串dataMemberName = ...;
变种dataMemberProperties = typeof运算(T)的.GetProperties()如(p值=> p.GetCustomAttributes(typeof运算(DataMemberAttribute),假)。任何())。
VAR propInfo = dataMemberProperties.Where(P =>((DataMemberAttribute)p.GetCustomAttributes(typeof运算(DataMemberAttribute),假的)。首先())名称== dataMemberName).FirstOrDefault();
这个作品,但感觉像它可以改进。我特别不喜欢 GetCustomAttributes()
被调用了两次。
怎样才可以重新编写好?理想的情况下,这将是巨大的,如果我可以做一个简单的一行代码。
//使用System.Linq的;
//使用的System.Reflection;
//使用System.Runtime.Serialization;
obj.GetType()
.GetProperties(...)
。凡(P => Attribute.IsDefined(P的typeof(DataMemberAttribute)))
。单(P =>((DataMemberAttribute)Attribute.GetCustomAttribute(
,P的typeof(DataMemberAttribute)))名称==富);
注:
-
Attribute.IsDefined
是用来检查一个自定义属性的presence无需下载数据。因此,它是比Attribute.GetCustomAttribute
更有效和用于跳过在第一步骤属性 -
在
其中,
运营商,我们剩下的属性有一个的DataMemberAttribute
:缺少这种属性属性已被过滤掉,并且它不能被应用超过一次。因此,我们可以使用Attribute.GetCustomAttribute
而不是Attribute.GetCustomAttributes
。
How can I reflectively get the property that has the DataMember with a given name (let's assume every DataMember has a unique name)? For example, in the following code the property with the DataMember that has name "p1" is PropertyOne
:
[DataContract(Name = "MyContract")]
public class MyContract
{
[DataMember(Name = "p1")]
public string PropertyOne { get; set; }
[DataMember(Name = "p2")]
public string PropertyTwo { get; set; }
[DataMember(Name = "p3")]
public string PropertyThree { get; set; }
}
Currently, I have:
string dataMemberName = ...;
var dataMemberProperties = typeof(T).GetProperties().Where(p => p.GetCustomAttributes(typeof(DataMemberAttribute), false).Any());
var propInfo = dataMemberProperties.Where(p => ((DataMemberAttribute)p.GetCustomAttributes(typeof(DataMemberAttribute), false).First()).Name == dataMemberName).FirstOrDefault();
This works, but it feels like it could be improved. I particularly don't like that GetCustomAttributes()
is called twice.
How can it be re-written better? Ideally, it would be great if I could make it a simple one-liner.
// using System.Linq;
// using System.Reflection;
// using System.Runtime.Serialization;
obj.GetType()
.GetProperties(…)
.Where(p => Attribute.IsDefined(p, typeof(DataMemberAttribute)))
.Single(p => ((DataMemberAttribute)Attribute.GetCustomAttribute(
p, typeof(DataMemberAttribute))).Name == "Foo");
Notes:
Attribute.IsDefined
is used to check for the presence of a custom attribute without retrieving its data. Thus it is more efficient thanAttribute.GetCustomAttribute
and used to skip properties in a first step.After the
Where
operator, we are left with properties that have exactly oneDataMemberAttribute
: Properties without this attribute have been filtered out, and it cannot be applied more than once. Therefore we can useAttribute.GetCustomAttribute
instead ofAttribute.GetCustomAttributes
.
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