Getting byte[] from PropertyInfo returns NULL

Question

I'm trying to get a Byte[] using reflection. Unfortunately the result it always NULL. The property is filled with data. Here's my code snippet.

public static void SaveFile(BusinessObject document)
{
    Type boType = document.GetType();
    PropertyInfo[] propertyInfo = boType.GetProperties();
    Object obj = Activator.CreateInstance(boType);
    foreach (PropertyInfo item in propertyInfo)
    {
        Type xy = item.PropertyType;
        if (String.Equals(item.Name, "Content") && (item.PropertyType == typeof(Byte[])))
        {
            Byte[] content = item.GetValue(obj, null) as Byte[];
        }
    }
    return true;
}

Here's the working code:

    public static void SaveFile(BusinessObject document)
{
    Type boType = document.GetType();
    PropertyInfo[] propertyInfo = boType.GetProperties();
    foreach (PropertyInfo item in propertyInfo)
    {
        if (String.Equals(item.Name, "Content") && (item.PropertyType == typeof(Byte[])))
        {
            Byte[] content = item.GetValue(document, null) as Byte[];
        }
    }
}

Answer 1

Your code looks strange. You are creating a new instance of the type of the parameter and try to get the value from that instance. You should be using the parameter itself instead:

public static void SaveFile(BusinessObject document)
{
    Type boType = document.GetType();
    PropertyInfo[] propertyInfo = boType.GetProperties();
    foreach (PropertyInfo item in propertyInfo)
    {
        Type xy = item.PropertyType;
        if (String.Equals(item.Name, "Content") &&
            (item.PropertyType == typeof(Byte[])))
        {
            Byte[] content = item.GetValue(document, null) as Byte[];
        }
    }
}

---

BTW:

1. return true in a method that returns void is illegal and will lead to a compiler error.

2. There is no need to use reflection in your case. You could simply write this:

   public static void SaveFile(BusinessObject document)
   {
       Byte[] content = document.Content;
       // do something with content.
   }
   

   This is only true if Content is defined on BusinessObject and not only on derived classes.

Answer 2

from your code snippet it appears you are not populating any value.

Object obj = Activator.CreateInstance(boType); 

this would just invoke the default consturctor and assign default values for all types. and for byte[] it is null

it should be

item.GetValue(document, null)