我有一个具有[key]属性的ViewModel,我想从该视图模型的实例中获取它.
I have a ViewModel which has a [key] property and i would like to get that from an instance of that view model.
我的代码看起来像这样(虚构模型)
My code looks something like this (fictional models)
class AddressViewModel { [Key] [ScaffoldColumn(false)] public int UserID { get; set; } // Foreignkey to UserViewModel } // ... somewhere else i do: var addressModel = new AddressViewModel(); addressModel.HowToGetTheKey..??所以我需要从ViewModel中获取UserID(在这种情况下).我该怎么办?
So i need to get the UserID(in this case) from the ViewModel. How can i do this?
推荐答案如果您对示例中的任何代码感到困惑或困惑,请添加注释,我将尽力提供帮助.
总而言之,您很有趣地使用 Reflection 遍历该类型的元数据以获得具有为其分配了给定属性的属性.
In summary, you are interesting in using Reflection to walk the meta-data of the type to get properties that have a given attribute assigned to them.
下面只是实现此目的的一种方法(有许多其他方法,也有许多提供相似功能的方法).
Below is just one way of doing this (there are many others and also many methods that provide similar functionality).
来自这个问题评论:
PropertyInfo[] properties = viewModelInstance.GetType().GetProperties(); foreach (PropertyInfo property in properties) { var attribute = Attribute.GetCustomAttribute(property, typeof(KeyAttribute)) as KeyAttribute; if (attribute != null) // This property has a KeyAttribute { // Do something, to read from the property: object val = property.GetValue(viewModelInstance); } }像乔恩(Jon)所说,请处理多个KeyAttribute声明以避免出现问题.此代码还假定您正在修饰public属性(不是非公共属性或字段),并且需要System.Reflection.
Like Jon says, handle multiple KeyAttribute declarations to avoid issues. This code also assumes you are decorating public properties (not, non-public properties or fields) and requires System.Reflection.
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从ViewModel获取[key]属性
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