How to get current property name via reflection?

Question

I would like to get property name when I\'m in it via reflection mechanism. Is it possible?

Update: I have code like this:

    public CarType Car
            


        

Answer 1

FWIW I implemented a system like this:

    [CrmAttribute("firstname")]
    public string FirstName
    {
       get { return GetPropValue<string>(MethodBase.GetCurrentMethod().Name); }
       set { SetPropValue(MethodBase.GetCurrentMethod().Name, value); }
    }

    // this is in a base class, skipped that bit for clairty
    public T GetPropValue<T>(string propName)
    {
        propName = propName.Replace("get_", "").Replace("set_", "");
        string attributeName = GetCrmAttributeName(propName);
        return GetAttributeValue<T>(attributeName);            
    }

    public void SetPropValue(string propName, object value)
    {
        propName = propName.Replace("get_", "").Replace("set_", "");
        string attributeName = GetCrmAttributeName(propName);
        SetAttributeValue(attributeName, value);
    }

    private static Dictionary<string, string> PropToAttributeMap = new Dictionary<string, string>();
    private string GetCrmAttributeName(string propertyName)
    {
         // keyName for our propertyName to (static) CrmAttributeName cache
         string keyName = this.GetType().Name + propertyName;
         // have we already done this mapping?
         if (!PropToAttributeMap.ContainsKey(keyName))
         {
             Type t = this.GetType();
             PropertyInfo info = t.GetProperty(propertyName);
             if (info == null)
             {
                 throw new Exception("Cannot find a propety called " + propertyName);
             }

             object[] attrs = info.GetCustomAttributes(false);
             foreach (object o in attrs)
             {
                 CrmAttributeAttribute attr = o as CrmAttributeAttribute ;
                 if (attr != null)
                 {
                     // found it. Save the mapping for next time.
                     PropToAttributeMap[keyName] = attr.AttributeName;
                     return attr.AttributeName;
                 }
              }
              throw new Exception("Missing MemberOf attribute for " + info.Name + "." + propertyName + ". Could not auto-access value");
           }

           // return the existing mapping
           string result = PropToAttributeMap[keyName];
           return result;
        }

There's also a custom attribute class called CrmAttributeAttribute.

I'd strongly recommend against using GetStackFrame() as part of your solution, my original version of the solution was originally the much neater:

return GetPropValue<string>();

But it was 600x slower than the version above.

Answer 2

Try using System.Diagnostics.StackTrace to reflect on the call stack. The property should be somewhere in the call stack (probably at the top if you're calling it directly from the property's code).

Answer 3

I'd like to know more about the context in which you need it since it seems to me that you should already know what property you are working with in the property accessor. If you must, though, you could probably use MethodBase.GetCurrentMethod().Name and remove anything after get_/set_.

Update:

Based on your changes, I would say that you should use inheritance rather than reflection. I don't know what data is in your dictionary, but it seems to me that you really want to have different Car classes, say Sedan, Roadster, Buggy, StationWagon, not keep the type in a local variable. Then you would have implementations of methods that do the proper thing for that type of Car. Instead of finding out what kind of car you have, then doing something, you then simply call the appropriate method and the Car object does the right thing based on what type it is.

 public interface ICar
 {
      void Drive( decimal velocity, Orientation orientation );
      void Shift( int gear );
      ...
 }

 public abstract class Car : ICar
 {
      public virtual void Drive( decimal velocity, Orientation orientation )
      {
          ...some default implementation...
      }

      public abstract void Shift( int gear );

      ...
 }

 public class AutomaticTransmission : Car
 {
       public override void Shift( int gear )
       {
          ...some specific implementation...
       }
 }

 public class ManualTransmission : Car
 {
       public override void Shift( int gear )
       {
          ...some specific implementation...
       }
 }

Answer 4

Yes, it is!

string test = "test string";
Type type = test.GetType();

PropertyInfo[] propInfos = type.GetProperties();
for (int i = 0; i < propInfos.Length; i++) 
{
    PropertyInfo pi = (PropertyInfo)propInfos.GetValue(i);
    string propName = pi.Name;
}

Answer 5

Slightly confusing example you presented, unless I just don't get it. From C# 6.0 you can use the nameof operator.

public CarType MyProperty
{
    get { return (CarType)this[nameof(MyProperty)]};
    set { this[nameof(MyProperty)] = value]};
}

If you have a method that handles your getter/setter anyway, you can use the C# 4.5 CallerMemberName attribute, in this case you don't even need to repeat the name.

public CarType MyProperty
{
    get { return Get<CarType>(); }
    set { Set(value); }
}

public T Get<T>([CallerMemberName]string name = null)
{
    return (T)this[name];
}   

public void Set<T>(T value, [CallerMemberName]string name = null)
{
    this[name] = value;
}  

Answer 6

Use MethodBase.GetCurrentMethod() instead!

Reflection is used to do work with types that can't be done at compile time. Getting the name of the property accessor you're in can be decided at compile time so you probably shouldn't use reflection for it.

You get use the accessor method's name from the call stack using System.Diagnostics.StackTrace though.

    string GetPropertyName()
    {
        StackTrace callStackTrace = new StackTrace();
        StackFrame propertyFrame = callStackTrace.GetFrame(1); // 1: below GetPropertyName frame
        string properyAccessorName = propertyFrame.GetMethod().Name;

        return properyAccessorName.Replace("get_","").Replace("set_","");
    }