Is there a way to create a delegate to get and set values for a FieldInfo?

Question

For properties there are GetGetMethod and GetSetMethod so that I can do:

Getter = (Func)Delegate.CreateDelegate(typeof(         


        

Answer 1

No there is no easy way to create a delegate to get/set a field.

You will have to make your own code to provide that functionallity. I would suggest two functions in a shared library to provide this.

Using your code (in this example I only show the creation of the get-delegate):

static public class FieldInfoExtensions
{
    static public Func CreateGetFieldDelegate(this FieldInfo fieldInfo)
    {
        var instExp = Expression.Parameter(typeof(S));
        var fieldExp = Expression.Field(instExp, fieldInfo);
        return Expression.Lambda>(fieldExp, instExp).Compile();
    }
}

This makes it easy to create a get-delegate from a FieldInfo (assuming the field is of type int):

Func getter = typeof(MyClass).GetField("MyField").CreateGetFieldDelegate();

Or if we change your code a little bit:

static public class TypeExtensions
{
    static public Func CreateGetFieldDelegate(this Type type, string fieldName)
    {
        var instExp = Expression.Parameter(type);
        var fieldExp = Expression.Field(instExp, fieldName);
        return Expression.Lambda>(fieldExp, instExp).Compile();
    }
}

This makes it even more easy:

Func getter = typeof(MyClass).CreateGetFieldDelegate("MyField");

It is also possible to create these delegates using IL, but that code would be more complex and does not have much more performance, if any.