38

I know that I can use the filterContext to get to it. However, this is not very flexible if the action method parameter is named differently. This should work:

[HttpGet]
[NewAuthoriseAttribute(SomeId = id)]
public ActionResult Index(int id)
{
    ...

public class NewActionFilterAttribute : ActionFilterAttribute
{   
    public int SomeId { get; set; }
    ...

but it does not (it does not even compile). Any ideas?

cs0815
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    Attributes are metadata and as such can only have constant values. – Davin Tryon Mar 20 '13 at 17:37
  • I think I came across this whilst googleing. I guess I could pass the name of the integer down to the attribute and then look for it in the filtercontext. what do you think? – cs0815 Mar 20 '13 at 17:40
  • Are you planning to base some of the authorization on a value sent to the application? Doesn't this give the user a chance to effect the authorization outcome? – Davin Tryon Mar 20 '13 at 17:46
  • No sorry - my actionfiltername was misleading. i have changed that. – cs0815 Mar 20 '13 at 18:00

2 Answers2

85

Building on the answer from @Pankaj and comments from @csetzkorn:

You pass the name of the parameter as a string then check the filterContext

public class NewAuthoriseAttribute : ActionFilterAttribute
{
    public string IdParamName { get; set; }

    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        if (filterContext.ActionParameters.ContainsKey(IdParamName))
        {
            var id = filterContext.ActionParameters[IdParamName] as Int32?;
        }
    }
}

[NewAuthorizeAttribute(IdParamName = "fooId")]
public ActionResult Index(int fooId)
{ ... }
Jasen
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  • What about if I want to pass the model state to this action filter? – Nick Gallimore May 22 '18 at 12:36
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    the "ContainsKey" method can throw an ArgumentNullException in case you decide to omit the "IdParamName" parameter. Be sure you check that: if (IdParamName != null && filterContext.ActionParameters.ContainsKey(IdParamName)) – Oscar Acevedo Apr 19 '21 at 19:01
2

Edit

I am assuming that you are looking to make the Alias of Parameter name. This is giving you the flexibility to have multiple Alias of your paramater Name.

enter image description here

ActionParameterAlias.ParameterAlias Overloads

enter image description here

If so, you can give alias like below.

[ParameterAlias("Original_Parameter_Name", 
                 "New_Parameter_Name")]
[ParameterAlias("Original_Parameter_Name", 
                 "New_Parameter_Name1")]
[ParameterAlias("Original_Parameter_Name", 
                 "New_Parameter_Name2")]
[ParameterAlias("Original_Parameter_Name", 
                 "New_Parameter_Name3")]

public ActionResult ActionMethod(Model ParameterValue) { return View(ParameterValue); }

Original Post

Try this one.

Attribute

public class NewAuthoriseAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        if (filterContext.ActionParameters.ContainsKey("id"))
        {
            var id = filterContext.ActionParameters["id"] as Int32?;
        }
    }
}

Action Method

Make sure to set the Parameter type nullable to avoid RunTime Crash.

[NewAuthoriseAttribute]
public ActionResult Index(Int32? id)
{
}
  • as I said - that's not an option and I am aware of this. The reason why I do not want to use this approach is that id can also be called a, b, c etc. – cs0815 Mar 20 '13 at 17:58
  • Then add the name of the ActionParameters key to the constructor of the attribute. –  Mar 20 '13 at 18:00