asp.net mvc 自定义属性
我正在尝试在 mvc 中创建一个自定义属性，以在视图中将其参数用作 breadCrumb。
好吧，这是属性的代码，
[AttributeUsage(AttributeTargets.All, AllowMultiple = true)]
public class BreadCrumbAttribute : Attribute {
public BreadCrumbAttribute(string title, string parent, string url) {
this._title = title;
this._parent = parent;
this._url = url;
}
#region named parameters properties
private string _title;
public string Title {
get { return _title; }
}
private string _url;
public string Url {
get { return _url; }
}
private string _parent;
public string Parent {
get { return _parent; }
}
#endregion
#region positional parameters properties
public string Comments { get; set; }
#endregion
}
这是属性的调用，
[BreadCrumbAttribute("tile", "parent name", "url")]
public ActionResult Index() {
//code goes here
}
这是我想要获取值的一种方式。 （这是部分视图）
System.Reflection.MemberInfo inf = typeof(ProductsController);
object[] attributes;
attributes = inf.GetCustomAttributes(typeof(BreadCrumbAttribute), false);
foreach (Object attribute in attributes) {
var bca = (BreadCrumbAttribute)attribute;
Response.Write(string.Format("{0}><a href={1}>{2}</a>", bca.Parent, bca.Url, bca.Title));
}
不幸的是，该属性没有按照我实现它的方式被调用。不过，如果我在类中添加属性而不是操作方法，它就会起作用。 我怎样才能让它发挥作用？
谢谢
I am trying to create a custom attribute in mvc to use it's parameters in a view as breadCrumb.
well, this is the code of the attribute
[AttributeUsage(AttributeTargets.All, AllowMultiple = true)]
public class BreadCrumbAttribute : Attribute {
public BreadCrumbAttribute(string title, string parent, string url) {
this._title = title;
this._parent = parent;
this._url = url;
}
#region named parameters properties
private string _title;
public string Title {
get { return _title; }
}
private string _url;
public string Url {
get { return _url; }
}
private string _parent;
public string Parent {
get { return _parent; }
}
#endregion
#region positional parameters properties
public string Comments { get; set; }
#endregion
}
this is the call of the attribute
[BreadCrumbAttribute("tile", "parent name", "url")]
public ActionResult Index() {
//code goes here
}
this is a way of how I'd like to get the values. (this is a partial view)
System.Reflection.MemberInfo inf = typeof(ProductsController);
object[] attributes;
attributes = inf.GetCustomAttributes(typeof(BreadCrumbAttribute), false);
foreach (Object attribute in attributes) {
var bca = (BreadCrumbAttribute)attribute;
Response.Write(string.Format("{0}><a href={1}>{2}</a>", bca.Parent, bca.Url, bca.Title));
}
Unfortunately, the attribute didn't get call with the way I implement it. Although, If I add the attribute in Class instead of an Action method it worked.
How could I make it work?
Thanks
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问题是您正在使用反射来获取类的属性，因此它自然不包括在操作方法上定义的属性。
要获得这些，您应该定义一个 ActionFilterAttribute，并在 OnActionExecuting 或 OnActionExecuted 方法中，您可以使用
filterContext.ActionDescriptor.GetCustomAttributes()方法 (此处的 MSDN 说明）。请注意，使用此解决方案，您可能会拥有两种不同类型的属性：第一个是您编写的属性，用于定义面包屑。第二个是查看执行操作的属性并构建面包屑（并且可能将其添加到 ViewModel 或将其粘贴到 HttpContext.Items 或其他内容中）。
The problem is that you are using reflection to get the attributes for the class, so naturally it does not include attributes defined on the action method.
To get those, you should define an ActionFilterAttribute, and in the OnActionExecuting or OnActionExecuted method, you can use
filterContext.ActionDescriptor.GetCustomAttributes()method (MSDN description here).Note that with this solution, you will likely have two different types of attributes: The first one is the one you wrote, to define the breadcrumbs. The second is the one that looks at the attributes on the executing action and builds up the breadcrumb (and presumably adds it to the ViewModel or sticks it in HttpContext.Items or something).