asp.net - Cannot get attribute from PropertyInfo c# -

i have class , interface set this:

public partial interface inav_item  {         [fieldid("df918977-369c-4a06-ac38-adb8741b5f75")]         string title  {get; set;} }   public partial class nav_item  : inav_item  {         [fieldid("df918977-369c-4a06-ac38-adb8741b5f75")]         public virtual string title  {get; set;} } 

and have class inherited:

public class menuitem : nav_item {         public virtual ienumerable<menuitem> children { get; set; }          //some other properties } 

i'm trying instantiate object of type menuitem, , trying attributes inherited class (i can't instantiate menuitem directly, because type being passed in other classes)

object obj = activator.createinstance(type);  foreach (propertyinfo propinfo in type.getproperties()) {             fieldattribute sfi =(fieldattribute)propinfo.propertytype.getcustomattribute(typeof(fieldattribute));  } 

but giving me sfi null. i've debugged try getting attributes:

propinfo.propertytype.getcustomattributes() 

.. giving me system attributes (type , else), own attributes not there? because class inherited? how can attribute value?

edit:

the attribute class defined this:

public class fieldidattribute : attribute {     private string _id;      public fieldattribute(string id)     {         _id = id;     }      public id thefieldid     {                 {             return new id(_id);         }     } } 

no, not inheritance problem. need change this:

fieldattribute sfi =(fieldattribute)propinfo.propertytype     .getcustomattribute(typeof(fieldattribute)); 

to this:

var sfi = propinfo.getcustomattribute(typeof(fieldidattribute)) fieldidattribute; 

this because propertytype returns type of property, i.e. string in case. , type string not have custom attribute.

also edit of fieldidattribute class not correct. it's constructor not match class name , features undeclared & incorrect id type.