检查酒店有属性 [英] Check if property has attribute

问题描述

由于属性中的一类，与属性 - 什么是确定它是否包含给定的属性最快的方法是什么？例如：

Given a property in a class, with attributes - what is the fastest way to determine if it contains a given attribute? For example:

    [IsNotNullable]
    [IsPK]
    [IsIdentity]
    [SequenceNameAttribute("Id")]
    public Int32 Id
    {
        get
        {
            return _Id;
        }
        set
        {
            _Id = value;
        }
    }

什么是确定例如，它拥有最快的方法IsIdentity属性？

What is the fastest method to determine that for example it has the "IsIdentity" attribute?

推荐答案

有在检索属性没有快速。但是，code应该是这样的（信贷Aaronaught）：

There's no fast in retrieving attributes. But code ought to look like this (credit to Aaronaught):

        var t = typeof(YourClass);
        var pi = t.GetProperty("Id");
        var hasIsIdentity = Attribute.IsDefined(pi, typeof(IsIdentity));

如果您需要检索属性的属性然后

If you need to retrieve attribute properties then

        var t = typeof(YourClass);
        var pi = t.GetProperty("Id");
        var attr = (IsIdentity[])pi.GetCustomAttributes(typeof(IsIdentity), false);
        if (attr.Length > 0) {
            // Use attr[0], you'll need foreach on attr if MultiUse is true
        }

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