Re: Passing property Accesor as Function`

> But ChangeType doesn't seem to work with nullables...Argh.

Previously posted here, but a ChangeType helper that DOES understand
Nullable<> and interfaces  From WilsonORMapper's QueryHelper class
(this supports a ton more conversions than Convert.ChangeType and goes
from object)...


/// <summary>
/// Convert a value to another type -- supports Nullable types, unlike
Convert.ChangeType.
/// </summary>
/// <param name="value">Value to be converted -- must be a value type.</param>
/// <param name="type">Type to convert value to -- must be a value type.</param>
/// <returns></returns>
static public object ChangeType(object value, Type type)
{
 if (value == null && type.IsGenericType)
   return Activator.CreateInstance(type);

 if (value == null)
   return null;

 if (type == value.GetType())
   return value;

 if (type.IsEnum)
 {
   if (value is string)
     return Enum.Parse (type, value as string);
   else
     return Enum.ToObject(type, value);
 }

 if (type.IsGenericType
     && type.GetGenericTypeDefinition().Equals(typeof(Nullable<>)))
   return Convert.ChangeType(value, Nullable.GetUnderlyingType(type));

 if (!type.IsInterface && type.IsGenericType)
 {
   Type innerType = type.GetGenericArguments()[0];
   object innerValue = QueryHelper.ChangeType(value, innerType); // recurse!
   return Activator.CreateInstance(type, new object[] { innerValue });
 }

 if (value is string && type == typeof(Guid))
   return new Guid(value as string);

 if (value is string && type == typeof(Version))
   return new Version(value as string);

 if (value is IConvertible)
   return Convert.ChangeType(value, type);
 else
   return value;
}

-- 
"He uses statistics as a drunken man uses lamp-posts… for support
rather than illumination." Andrew Lang

Marc C. Brooks
http://musingmarc.blogspot.com