how to set nullable type via reflection code ( c#)?

Question

I need to set the properties of a class using reflection.

I have a Dictionary<string,string> with property names and string values.

Inside a reflection loop, I need to convert the string value to the appropriate property type while setting the value for each property. Some of these property types are nullable types.

1. How can I know from PropertyInfo if the property is a nullable type?
2. How can I set a nullable type using reflection?

edit: The first method defined in the comments on this blog seems to do the trick as well: http://weblogs.asp.net/pjohnson/archive/2006/02/07/437631.aspx

Answer 1

1. One way to do this is:

   type.GetGenericTypeDefinition() == typeof(Nullable<>) 

2. Just set is as per any other reflection code:

   propertyInfo.SetValue(yourObject, yourValue); 

Answer 2

Why do you need to know if it is nullable? And do you mean "reference-type", or "Nullable<T>"?

Either way, with string values, the easiest option would be via the TypeConverter, which is more-easily (and more accurately) available on PropertyDescriptor:

PropertyDescriptorCollection props = TypeDescriptor.GetProperties(obj); // then per property... PropertyDescriptor prop = props[propName]; prop.SetValue(obj, prop.Converter.ConvertFromInvariantString(value)); 

This should use the correct converter, even if set per-property (rather than per-type). Finally, if you are doing lots of this, this allows for acceleration via HyperDescriptor, without changing the code (other than to enable it for the type, done once only).