类似于下面的，，这将只使用它经过的第一个属性，它有属性，当然你可以把它放在多个。

public object GetIDForPassedInObject(T obj)
    {
        var prop = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance)
                   .FirstOrDefault(p => p.GetCustomAttributes(typeof(IdentifierAttribute), false).Count() ==1);
        object ret = prop !=null ?  prop.GetValue(obj, null) : null;

        return ret;
    }

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public class TestClass<T>
{
    public void GetIDForPassedInObject(T obj)
    {
        PropertyInfo[] properties =
            obj.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance);            

        PropertyInfo IdProperty = (from PropertyInfo property in properties
                           where property.GetCustomAttributes(typeof(Identifier), true).Length > 0
                           select property).First();

         if(null == IdProperty)
             throw new ArgumentException("obj does not have Identifier.");

         Object propValue = IdProperty.GetValue(entity, null)
    }
}

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有点晚了，但这里是我为枚举（也可以是任何对象）做的一些事情，并使用扩展获取description属性值（这可以是任何属性的泛型）：

public enum TransactionTypeEnum
{
    [Description("Text here!")]
    DROP = 1,

    [Description("More text here!")]
    PICKUP = 2,

    ...
}

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获取值：

var code = TransactionTypeEnum.DROP.ToCode();

型
支持我所有枚举的扩展：

public static string ToCode(this TransactionTypeEnum val)
{
    return GetCode(val);
}

public static string ToCode(this DockStatusEnum val)
{
    return GetCode(val);
}

public static string ToCode(this TrailerStatusEnum val)
{
    return GetCode(val);
}

public static string ToCode(this DockTrailerStatusEnum val)
{
    return GetCode(val);
}

public static string ToCode(this EncodingType val)
{
    return GetCode(val);
}

private static string GetCode(object val)
{
    var attributes = (DescriptionAttribute[])val.GetType().GetField(val.ToString()).GetCustomAttributes(typeof(DescriptionAttribute), false);

    return attributes.Length > 0 ? attributes[0].Description : string.Empty;
}

型

示例

我用一个属性acceptances参数和works一个属性扩展了您的示例

[AttributeUsage(AttributeTargets.Property,AllowMultiple = true)]
public class PersonAttribute : Attribute
{
    public readonly string FieldName;
    public readonly string FieldType;
    public PersonAttribute(string name,string type)
    {
        FieldName = name;
        FieldType = type;
    }    
}

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该属性应用于Person类上的，如下所示：

public class Person
{
    public string FirstName {get;set;} = "FirstName";
    public string LastName {get;set;} = "LastName";
    
    [Person("addressline1","db")]
    [Person("new_address1","system")]
    public string AddressLine1 {get;set;} = "Banglore";
    
    [Person("addressline2","system")]
    public string AddressLine2 {get;set;} = "Karnataka";
    
    [Person("addressline3","dto")]
    public string AddressLine3 {get;set;} = "INDIA";    
}

型

溶液

我已经创建了下面的扩展函数，它是通用的，能够从类中读取所有属性和属性值。

public static class AttributesExt
{
    public static IEnumerable<PropertyInfo> AllAttributes<T>(this object obj,string name)
    {
        var allProperties = obj.GetType().GetProperties()
        .Where(_ => _.GetCustomAttributes(typeof(T), true).Length >= 1  && _.Name == name);
        return allProperties;
    }
    
    public static IEnumerable<PropertyInfo> AllAttributes<T>(this object obj)
    {
        var allProperties = obj.GetType().GetProperties()
        .Where(_ => _.GetCustomAttributes(typeof(T), true).Length >= 1);
        return allProperties;
    }

    public static T ReadAttribute<T>(this PropertyInfo propertyInfo)
    {
        var returnType = propertyInfo.GetCustomAttributes(typeof(T), true)
        .Cast<T>().FirstOrDefault();
        return returnType;
    }
}

型
现在在main方法中，如果我们写

void Main()
{
    Person p = new Person();
    
    var all = p.AllAttributes<PersonAttribute>().Dump(); //Get All custom attributes
    p.AllAttributes<PersonAttribute>("AddressLine3").Dump();
    all.First(_=> _.Name == "AddressLine2").ReadAttribute<PersonAttribute>().Dump();
    all.First(_=> _.Name == "AddressLine2").ReadAttribute<PersonAttribute>().FieldName.Dump();
}

型
我们可以按照下面的截图读取这些值。

的数据

这里有一个更真实的例子。我们使用扩展方法并检查属性是否包含FieldMetaDataAttribute（源代码库中的一个自定义属性），该属性具有有效的Major和MinorVersion。一般感兴趣的是我们使用父类类型和GetProperties并检索PropertyInfo，然后在这种特殊情况下使用GetCustomAttribute检索属性FieldMetaDataAttribute的部分。使用这段代码启发如何更通用地检索自定义属性。当然，这可以被完善，以形成一个通用的方法来检索类示例的任何属性的给定属性。

/// <summary>
    /// Executes the action if not the field is deprecated 
    /// </summary>
    /// <typeparam name="TProperty"></typeparam>
    /// <typeparam name="TForm"></typeparam>
    /// <param name="form"></param>
    /// <param name="memberExpression"></param>
    /// <param name="actionToPerform"></param>
    /// <returns>True if the action was performed</returns>
    public static bool ExecuteActionIfNotDeprecated<TForm, TProperty>(this TForm form, Expression<Func<TForm, TProperty>> memberExpression, Action actionToPerform)
    {
        var memberExpressionConverted = memberExpression.Body as MemberExpression;
        if (memberExpressionConverted == null)
            return false; 

        string memberName = memberExpressionConverted.Member.Name;

        PropertyInfo matchingProperty = typeof(TForm).GetProperties(BindingFlags.Public | BindingFlags.Instance)
            .FirstOrDefault(p => p.Name == memberName);
        if (matchingProperty == null)
            return false; //should not occur

        var fieldMeta = matchingProperty.GetCustomAttribute(typeof(FieldMetadataAttribute), true) as FieldMetadataAttribute;
        if (fieldMeta == null)
        {
            actionToPerform();
            return true;
        }

        var formConverted = form as FormDataContract;
        if (formConverted == null)
            return false;

        if (fieldMeta.DeprecatedFromMajorVersion > 0 && formConverted.MajorVersion > fieldMeta.DeprecatedFromMajorVersion)
        {
            //major version of formConverted is deprecated for this field - do not execute action
            return false;
        }

        if (fieldMeta.DeprecatedFromMinorVersion > 0 && fieldMeta.DeprecatedFromMajorVersion > 0
                                                     && formConverted.MinorVersion >= fieldMeta.DeprecatedFromMinorVersion
                                                     && formConverted.MajorVersion >= fieldMeta.DeprecatedFromMajorVersion)
            return false; //the field is expired - do not invoke action 
        actionToPerform();
        return true;
    }

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